OPERATIONAL CHECKS & SAFETY CIRCUIT DESCRIPTION

(1)

O

PERATIONAL

C

HECKS

& S

AFETY

C

IRCUIT

D

ESCRIPTION

• Integrated control module performs internal checks.

• Integrated control module displays 88888 88888 on dual 7-segment

display LED’s.

• Integrated control module monitors safety circuits

continuously.

• Furnace awaits call from thermostat. Dual 7-segment LED’s

display 00000 PPPPP while awaiting call from thermostat.

H

EATING

M

ODE

The normal operational sequence in heating mode is as follows:

• R and W1 (or R and W1/W2) thermostat contacts close,

initiating a call for heat.

• Integrated control module performs safety circuit checks.

• Induced draft blower is energized on high speed for a

15-second prepurge. Humidifier terminal is energized with

induced draft blower.

• Induced draft blower steps to low speed following prepurge.

Low stage pressure switch contacts are closed.

• Igniter warm up begins upon step to low speed and

presence of closed low stage pressure switch contacts.

• Gas valve opens at end of igniter warm up period, delivering

gas to burners and establishing flame.

• Integrated control module monitors flame presence. Gas

valve will remain open only if flame is detected.

• If the thermostat call is for low heat, gas valve and induced

draft blower will continue on low stage. If the call is for high

heat, the gas valve and induced draft blower will change to

high stage.

• Circulator blower is energized on heat speed following a

thirty (30) second blower on delay. The circulator blower

requires thirty seconds to ramp up to full speed. Electronic

air cleaner terminal is energized with circulator blower.

• Furnace is now operating on the specified stage called for

by the two-stage thermostat.

• Furnace runs, integrated control module monitors safety

circuits continuously.

• If the two-stage thermostat changes the call from low heat

to high heat, the integrated control module will immediately

switch the induced draft blower, gas valve, and circulator

blower to their high stage settings.

• If the two-stage thermostat changes the call from high heat

to low heat, the control will immediately switch the induced

draft blower and gas valve to their low stage settings. The

circulator blower will remain on high heating speed for thirty

(30) seconds before switching to the low heat circulating

speed.

• R and W1 (or R and W1/W2) thermostat contacts open,

completing the call for heat.

• Gas valve closes, extinguishing flame.

• Induced draft blower is de-energized following a fifteen second

post purge. Humidifier terminals are de-energized.

• Circulator blower continues running for the selected heat

off delay period (90, 120, 150 or 180 seconds). The speed

run during this period depends on the last heat call provided

by the thermostat.

If the last call for heat was a call for low heat, the air circulator

motor will run on low heat speed for the duration of the heat

off delay period (90, 120, 150 or 180 seconds).

If the last call for heat was a call for high heat, the air

circulating motor will run on the high heating speed for thirty

(30) seconds and then switch to the low heating speed for

the balance of the heat off delay period (60, 90, 120 or 150

seconds).

• Circulator blower and electronic air cleaner terminal is

de-energized.

• Circulator blower ramps down to OFF during the 30 seconds

following the heat off delay period.

• Furnace awaits next call from thermostat.

C

OOLING

M

ODE

The normal operational sequence in cooling mode is as follows:

• R and Y1/G or Y2/G thermostat contacts close, initiating a

call for cool.

• Integrated control module performs safety circuit checks.

• Outdoor fan and compressor are energized to their

appropriate speed.

• Circulator blower is energized on the appropriate cool speed

at the level and time determined by the selected ramping

profile. Electronic air cleaner terminal is energized with

circulator blower.

• Furnace circulator blower and outdoor cooling unit run their

appropriate speeds, integrated control module monitors

safety circuits continuously.

• R and Y1/G or Y2/G thermostat contacts open, completing

the call for cool.

• Outdoor fan and compressor are de-energized.

• Circulator blower continues running during a cool off delay

period. The OFF delay time and airflow level are determined

by the selected ramping profile.

• Electronic air cleaner terminal and circulator blower are

de-energized.

• Furnace awaits next call from thermostat.

F

AN

O

NLY

M

ODE

The normal operational sequence in fan only mode is as follows:

• R and G thermostat contacts close, initiating a call for fan.

• Integrated control module performs safety circuit checks.

(2)

T

ROUBLESHOOTING

& M

AINTENANCE

• Circulator blower is energized on continuous fan speed (30%

of the furnace’s maximum airflow capability) following a five

(5) second delay. Electronic air cleaner terminal is energized.

• Circulator blower runs, integrated control module monitors

safety circuits continuously.

• R and G thermostat contacts open, completing the call for

fan.

• Circulator blower is de-energized. Electronic air cleaner

terminal is de-energized.

• Furnace awaits next call from thermostat.

O

PERATIONAL

C

HECKS

The burner flames should be inspected with the burner

compart-ment door installed. Flames should be stable, quiet, soft, and

blue (dust may cause orange tips but they must not be yellow).

Flames should extend directly outward from the burners without

curling, floating, or lifting off. Flames must not impinge on the

sides of the heat exchanger firing tubes.

Burner Flame

S

AFETY

C

IRCUIT

D

ESCRIPTION

A number of safety circuits are employed to ensure safe and proper

furnace operation. These circuits serve to control any potential

safety hazards and serve as inputs in the monitoring and

diagno-sis of abnormal function. These circuits are continuously

moni-tored during furnace operation by the integrated control module.

I

NTEGRATED

C

ONTROL

M

ODULE

The integrated control module is an electronic device which, if a

potential safety concern is detected, will take the necessary

pre-cautions and provide diagnostic information through an LED.

P

RIMARY

L

IMIT

The primary limit control is located on the partition panel and

moni-tors heat exchanger compartment temperatures. It is a

normally-closed (electrically), automatic reset, temperature-activated

sen-sor. The limit guards against overheating as a result of insufficient

conditioned air passing over the heat exchanger.

A

UXILIARY

L

IMIT

The auxiliary limit controls are located on or near the circulator

blower and monitors blower compartment temperatures. They are

a normally-closed (electrically), manual-reset sensors. These

lim-its guard against overheating as a result of insufficient conditioned

air passing over the heat exchanger.

R

OLLOUT

L

IMIT

The rollout limit controls are mounted on the burner/manifold

as-sembly and monitor the burner flame. They are normally-closed

(electrically), manual-reset sensors. These limits guard against

burner flames not being properly drawn into the heat exchanger.

P

RESSURE

S

WITCHES

The pressure switches are normally-open (closed during

opera-tion) negative air pressure-activated switches. They monitor the

airflow (combustion air and flue products) through the heat

ex-changer via pressure taps located on the induced draft blower and

the coil front cover. These switches guard against insufficient

air-flow (combustion air and flue products) through the heat exchanger

and/or blocked condensate drain conditions.

F

LAME

S

ENSOR

The flame sensor is a probe mounted to the burner/manifold

as-sembly which uses the principle of flame rectification to determine

the presence or absence of flame.

T

ROUBLESHOOTING

E

LECTROSTATIC

D

ISCHARGE

(ESD) P

RECAUTIONS

NOTE: Discharge body’s static electricity before touching unit.

An electrostatic discharge can adversely affect electrical

components.

Use the following precautions during furnace installation and

ser-vicing to protect the integrated control module from damage. By

putting the furnace, the control, and the person at the same

elec-trostatic potential, these steps will help avoid exposing the

inte-grated control module to electrostatic discharge. This procedure

is applicable to both installed and uninstalled (ungrounded)

fur-naces.

1. Disconnect all power to the furnace. Do not touch the

integrated control module or any wire connected to the

control prior to discharging your body’s electrostatic charge

to ground.

2. Firmly touch a clean, unpainted, metal surface of the furnace

away from the control. Any tools held in a person’s hand

during grounding will be discharged.

3. Service integrated control module or connecting wiring

following the discharge process in step 2. Use caution not

to recharge your body with static electricity; (i.e., do not

move or shuffle your feet, do not touch ungrounded objects,

etc.). If you come in contact with an ungrounded object,

repeat step 2 before touching control or wires.

4. Discharge your body to ground before removing a new

control from its container. Follow steps 1 through 3 if

installing the control on a furnace. Return any old or new

controls to their containers before touching any ungrounded

object.

(3)

T

ROUBLESHOOTING

& M

AINTENANCE

D

IAGNOSTIC

C

HART

HIGH VOLTAGE !

T

O

AVOID

PERSONAL

INJURY

OR

DEATH

DUE

TO

ELECTRICAL

SHOCK

,

DISCONNECT

ELECTRICAL

POWER

BEFORE

PERFORMING

ANY

SERVICE

OR

MAINTENANCE

.

WARNING

Refer to the Troubleshooting Chart in the Appendix for assistance

in determining the source of unit operational problems. The dual

7-segment LED display will display an error code that may contain a

letter and number. The error code may be used to assist in

trouble-shooting the unit.

R

ESETTING

F

ROM

L

OCKOUT

Furnace lockout results when a furnace is unable to achieve

igni-tion after three attempts during a single call for heat. It is

charac-terized by a non-functioning furnace and a E 0 code displayed on

the dual 7-segment display. If the furnace is in “lockout”, it will (or

can be) reset in any of the following ways.

1. Automatic reset. The integrated control module will

automatically reset itself and attempt to resume normal

operations following a one hour lockout period.

2. Manual power interruption. Interrupt 115 volt power to the

furnace.

3. Manual thermostat cycle. Lower the thermostat so that

there is no longer a call for heat for 1 -20 seconds then

reset to previous setting.

NOTE: If the condition which originally caused the lockout still

exists, the control will return to lockout. Refer to the Troubleshooting

Chart for aid in determining the cause.

M

AINTENANCE

T

O

AVOID

ELECTRICAL

SHOCK

,

INJURY

OR

DEATH

,

DISCONNECT

ELECTRICAL

POWER

BEFORE

PERFORMING

ANY

MAINTENANCE

. I

F

YOU

MUST

HANDLE

THE

IGNITER

,

HANDLE

WITH

CARE

. T

OUCHING

THE

IGNITER

ELEMENT

WITH

BARE

FINGERS

,

ROUGH

HANDLING

OR

VIBRATION

COULD

DAMAGE

THE

IGNITER

RESULTING

IN

PREMATURE

FAILURE

. O

NLY

A

QUALIFIED

SERVICER

SHOULD

EVER

HANDLE

THE

IGNITER

.

WARNING

A

NNUAL

I

NSPECTION

The furnace should be inspected by a qualified installer, or service

agency at least once per year. This check should be performed at

the beginning of the heating season. This will ensure that all

fur-nace components are in proper working order and that the heating

system functions appropriately. Pay particular attention to the

fol-lowing items. Repair or service as necessary.

• Flue pipe system. Check for blockage and/or leakage.

Check the outside termination and the connections at

and internal to the furnace.

• Heat exchanger. Check for corrosion and/or buildup within

the heat exchanger passageways.

• Burners. Check for proper ignition, burner flame, and

flame sense.

• Drainage system. Check for blockage and/or leakage.

Check hose connections at and internal to furnace.

• Wiring. Check electrical connections for tightness and/

or corrosion. Check wires for damage.

• Filters.

F

ILTERS

T

O

ENSURE

PROPER

UNIT

PERFORMANCE

,

ADHERE

TO

THE

FILTER

SIZES

GIVEN

IN

THE

RECOMMENDED

M

INIMUM

F

ILTER

S

IZE

T

ABLE

OR

S

PECIFICATION

S

HEET

APPLICABLE

TO

YOUR

MODEL

.

CAUTION

F

ILTER

M

AINTENANCE

Improper filter maintenance is the most common cause of

inad-equate heating or cooling performance. Filters should be cleaned

(permanent) or replaced (disposable) every two months or as

re-quired. When replacing a filter, it must be replaced with a filter of

the same type and size.

F

ILTER

R

EMOVAL

Depending on the installation, differing filter arrangements can be

applied. Filters can be installed in either the central return register

or a side panel external filter rack (upflow only). A media air filter or

electronic air cleaner can be used as an alternate filter. Follow the

filter sizes given in the Recommended Minimum Filter size table

to ensure proper unit performance.

To remove filters from an external filter rack in an upright upflow

installation, follow the directions provided with external filter rack

kit.

H

ORIZONTAL

U

NIT

F

ILTER

R

EMOVAL

Filters in horizontal installations are located in the central return

register or the ductwork near the furnace.

To remove:

1. Turn OFF electrical power to furnace.

2. Remove filter(s) from the central return register or ductwork.

3. Replace filter(s) by reversing the procedure for removal.

4. Turn ON electrical power to furnace.

M

EDIA

A

IR

F

ILTEROR

E

LECTRONIC

A

IR

C

LEANER

R

EMOVAL

(4)

M

ISCELLANEOUS

B

URNERS

Visually inspect the burner flames periodically during the heating

season. Turn on the furnace at the thermostat and allow several

minutes for flames to stabilize, since any dislodged dust will alter

the flames normal appearance. Flames should be stable, quiet,

soft, and blue (dust may cause orange tips but they must not be

yellow). They should extend directly outward from the burners

without curling, floating, or lifting off. Flames must not impinge on

the sides of the heat exchanger firing tubes.

I

NDUCED

D

RAFT

AND

C

IRCULATOR

B

LOWERS

The bearings in the induced draft blower and circulator blower

mo-tors are permanently lubricated by the manufacturer. No further

lubrication is required. Check motor windings for accumulation of

dust which may cause overheating. Clean as necessary.

C

ONDENSATE

T

RAP

AND

D

RAIN

S

YSTEM

(Q

UALIFIED

S

ERVICER

O

NLY

)

Annually inspect the drain tubes, drain trap, and field-supplied drain

line for proper condensate drainage. Check drain system for hose

connection tightness, blockage, and leaks. Clean or repair as

necessary.

F

LAME

S

ENSOR

(Q

UALIFIED

S

ERVICER

O

NLY

)

Under some conditions, the fuel or air supply can create a nearly

invisible coating on the flame sensor. This coating acts as an

insulator causing a drop in the flame sense signal. If the flame

sense signal drops too low the furnace will not sense flame and

will lock out. The flame sensor should be carefully cleaned by a

qualified servicer using emery cloth or steel wool. Following

clean-ing, the flame sense signal should be as indicated in the

Specifica-tions Sheet.

F

LUE

P

ASSAGES

(Q

UALIFIED

S

ERVICER

O

NLY

)

The heat exchanger flue passageways should be inspected at the

beginning of each heating season. If necessary, clean the

pas-sageways as outlined below.

1. Turn OFF the electrical power and gas supply to the furnace.

2. Disconnect the gas line and remove the burner/ manifold

assembly by removing the screws securing the assembly

to the partition panel.

3. Disconnect the flue pipe system from the induced draft

blower.

4. Remove the induced draft blower, drain and pressure tap

hoses from the recuperator coil front cover.

5. Remove the recuperator coil front cover to expose the coil

tubes and turbulators.

6. Remove the recuperator coil turbulators individually by

slowly pulling each turbulator forward firmly.

7. Clean the recuperator coil tubes using a long handle wire

brush, such as a gun cleaning brush.

8. Clean the primary heat exchanger tubes using a wire brush

attached to a length of high grade stainless steel cable,

such as drain cleanout cable. Attach a variable speed

reversible drill to the other end of the cable. Slowly rotate

the cable with the drill and insert it into one of the heat

exchanger tubes. While reversing the drill, work the cable

in and out several times to obtain sufficient cleaning. Repeat

for each tube.

9. Clean residue from furnace using a vacuum cleaner.

10. Replace the parts removed in the previous steps in reverse

order.

11. Turn on electrical power and gas to furnace. Check for

leaks and proper unit operation.

12. Severe heat exchanger fouling is an indication of an

operational problem. Perform the checks listed in Startup

Procedure and Adjustments to reduce the chances of

repeated fouling.

B

EFORE

L

EAVING

AN

I

NSTALLATION

• Cycle the furnace with the thermostat at least three times.

Verify cooling and fan only operation.

• Review the Owner’s Manual with the homeowner and

discuss proper furnace operation and maintenance.

• Leave literature packet near furnace.

R

EPAIR

AND

R

EPLACEMENT

P

ARTS

• When ordering any of the listed functional parts, be sure to

provide the furnace model, manufacturing, and serial

numbers with the order.

• Although only functional parts are shown in the parts list,

all sheet metal parts, doors, etc. may be ordered by

description.

• Parts are available from your distributor.

Functional Parts

List-Gas Valve

Blower Motor

Gas Manifold

Blower Wheel

Natural Gas Orifice

Blower Mounting Bracket

Propane Gas Orifice

Blower Cutoff

Igniter

Blower Housing

Flame Sensor

Inductor

Rollout Limit Switch

Heat Exchanger with

Primary Limit Switch

Recuperator Coil

Auxiliary Limit Switch

Coil Front Cover

Pressure Switch

Integrated Control Module

Induced Draft Blower

Transformer

(5)

D

IP

S

WITCHES

1

2

3

4

5

6

7

8

9

10 90 s ec onds

OFF

---

---120 s ec onds

ON

OFF

---

---150 s econds *

OFF

ON

---

---180 s ec onds

ON

---

---1-Stage T-stat

---

OFF

---

---2-Stage T-Stat

---

ON

---

---5-Min Delay

---

OFF

---

---A uto Delay

---

ON

---

---Bus BIA S

BIA S

ON*

---

---TERM

Bus Termination

---

ON*

---

---A

OFF

---

---B

ON

OFF

---

---C

OFF

ON

---

---D*

ON

---

---Normal*

---

OFF

---

---10%

---

ON

OFF

---

----10%

---

OFF

ON

---

---Normal

---

ON

---

---A *

---

OFF

---

---B

---

ON

OFF

---

---C

---

OFF

ON

---

---D

---

ON

---

---A

---

OFF

---

---B*

---

ON

OFF

---

---C

---

OFF

ON

---

---D

---

ON

---

---Dis abled*

---

OFF

Unus ed

Enabled

---

ON

Unus ed

---

Not applic able

Cooling

Speed Tap

A djus t

Taps

S3

Ramping

Prof iles

DIP Sw itc h No.

Thermos tat

Setup

S1

S2

Sw itch

Bank

Pur pos e

Heat OFF

Delay

Function

(*Indic ates f ac tory s etting)

Heating

Speed Tap

DEHUM

S5

S4

(6)

T

ROUBLESHOOTING

C

HART

Co m fo r tNet™ Therm ost a t On ly Sym ptom s of A bnor m a l Opera ti on (Le g ac y & Com fortNet™ Th erm o stat ) D ia g no st ic /St a tus LED Codes Fault De scr ipt ion Messa ge Code P o ss ib le C a u se s Correct ive Action s No tes & Ca utio ns x Fur nace fa ils to opera te x Int egr ate d c o ntr o l m o du le L E D di sp lay p rovi des n o s ign al . x Com fortNet™ therm o st at “ C all for Service” ic on illum inate d x Com fortNet™ therm os ta t scr o lls “ C heck Fur nace” m essa ge N one x No 115 powe r to fur n ace o r no 24 v o lt po wer to in te gra te d co n tro l m odule x Blow n f u se or c irc ui t brea ker x In te g ra ted con trol m odule has an in ter n al fau lt INTERNAL FAULT EE x Manu al di sconn ect swi tc h OFF, d o o r s w it ch op en o r 24 vo lt wi re im p ro p erl y co nn ect ed o r lo os e x Blow n f u se or c irc ui t brea ker x Int egr ate d c o ntr o l m o du le has an in ter na l fa ul t x A ss u re 1 1 5 a nd 24 v o lt pow er t o fur nace a n d integr ate d control m odule. x Ch eck int eg rated cont rol m o d u le fuse (3A). Re place if nece ssary . x Ch eck fo r pos si b le s h o rts in 1 1 5 and 24 vo lt ci rcu its . Rep ai r as nece ss ary . x Replace ba d integr ate d control m odule. x T u rn pow er O F F pr io r to repa ir. x Replace inte gra te d contr o l m odule f u se w it h 3A au to m o ti v e f u se. x Read prec autions in “E lectros tatic Disc ha rge” sec ti o n of m anua l. x Replace inte gra te d contr o l m odule w ith cur ren t replacem ent parts. x L E D dis p lay in di cat es OP

OP

x Norm al opera tion N one N one x Norm al opera tion x N one x Norm al opera tion x Fur nace fa ils to opera te x Int egr ate d c o ntr o l m o du le L E D di sp lay p rovi des E0 err o r code. x Com fortNet™ therm o st at “ C all for Service” ic on illum inate d. x Com fortNet™ therm os ta t scr o lls “ C heck Fur nace” m essa ge.

E0

x Fur n

ace lockout due

to an e x ce ss ive num ber of ig ni ti on “ ret ri es ” (3 to ta l) LOCKOUT E0 x Failur e to es ta blish f la m e. Cause m a y be no gas to b u rn er s, fro n t co ver p res su re sw it ch st uc k o p en , b ad ig ni ter or ig ni ter al ign m en t, im proper or ifi ces, or co at ed /ox id ized o r i m p rop erl y conne cte d f lam e sens or. x Los s of f lam e after es tablis hm ent. Cau se m a y be inte rru pte d gas su p p ly , lazy burne r fl am es (im prope r ga s pr es su re or rest ricti on in fl ue and/ o r co m b u st ion ai r p ipi ng ), front co ver p res su re sw it ch ope n in g , or im proper in d u ce d d ra ft b low er perf o rm ance. x Locate and c o rre ct ga s in terr u p ti on. x Chec k fr on t c o v er pr es su re sw it ch op erat ion (hose, wi rin g , co n tac t o p er at io n) . C o rr ect if nece ss ary . x Replace or rea lign igniter. x Chec k f lam e sense signal. Sa nd se nso r i f co at ed an d/or o x id iz ed . x Chec k f lue p ip in g f o r bl oc ka ge, p rop er l eng th , elbo w s, an d term inat ion. x Veri fy p rop er ind u ced d raft bl ow er perf orm ance. x T u rn pow er O F F pr io r to repa ir. x Ig nit er is fragi le , h and le with care. x Sand flam e sensor with e m ery cloth. x See “ V ent/Flue P ipe ” se ct ion fo r p ipi ng d etai ls . x Fur nace fa ils to opera te. x Int egr ate d c o ntr o l m o du le L E D di sp lay p rovi des E1 err o r code. x Com fortNet™ therm o st at “ C all for Service” ic on illum inate d. x Com fortNet™ therm os ta t scr o lls “ C heck Fur nace” m essa ge.

E1

x Lo w s tag e p res su re sw it ch ci rc ui t is clo se d a t sta rt of heating cy cle. P S1 CLOSED E1 x Lo w st ag e p res su re swi tc h con tacts st ickin g . x Sh orts in pressu re s w it ch ci rcu it w iri ng. x

Replace low sta

g e pr ess ure sw it ch. x Repa ir s h or t i n w ir in g . x T u rn pow er O F F pr io r to repa ir. x Replace pre ssure switch with cor rec t re pla cem ent par t. x In du ced d raft blo w er ru ns co nti nuo usl y wi th no furth er fu rn ace op erat ion . x Int egr ate d c o ntr o l m o du le L E D di sp lay p rovi des E2 err o r code. x Com fortNet™ therm o st at “ C all for Service” ic on illum inate d. x Com fortNet™ therm os ta t scr o lls “ C heck Fur nace” m essa ge.

E2

x Lo w s tag e p res su re sw it ch ci rc u it is no t close d . PS 1 OPEN E2 x Pres su re sw it ch h o se bl oc ke d pi nc he d, or c o nne cte d im pro p erly . x Bl ocked fl ue and/ o r in le t ai r pip e, bl oc ke d dr ai n sy stem or w ea k in d u ce d dr aft bl ow er. x Inc o rrec t pre ssure switc h set point or m alfunc ti o n in g sw itc h conta cts. x Loose or im properly conne cte d w iri ng. x In sp ect p res su re s w itch hos e. Repa ir /re pla ce if nec essa ry . x Ins pe ct f lu e an d /or in let a ir p ipi ng fo r bl ockag e, p rop er len g th, e lbow s, an d te rm inat ion. x Chec k drain sy stem . Corre ct as nece ssary . x Chec k i n d u ce d dra ft bl ow er perf orm ance. Corr ect as nece ss ary . x Co rrect p res su re s w itch set p o in t or c o n tac t m o tio n. x Tighte n or c o rrec t wiring co nne ct ion. x T u rn pow er O F F pr io r to repa ir. x Replace pre ssure switch with cor rec t re pla cem ent par t. x Replace induce d draf t blower with corr ec t replacem ent part.

(7)

T

ROUBLESHOOTING

C

HART

Co m fo r tNet™ Therm ost a t On ly ptom s of A bnor m a l Opera ti on ac y & C o m fort N et™ Therm o st at) D ia g no st ic /St a tus LED Codes Fault De scr ipt ion Messa ge Code P o ss ib le C a u se s Correct ive Action s No tes & Ca utio ns lato r b lo w er ru ns cont inu o u sl y . No n ace opera tion. egr ate d c o ntr o l m o du le L E D di sp lay des E3 err o r code. fortNet™ therm o st at “ C all for on illum inate d. fortNet™ therm os ta t scr o lls “ C heck nace” m essa ge.

E3

x Prim ary li m it or au xi li ary lim it circu it is op en. x Ro llo ut li m it ci rcui t is op en.

HIGH LIMIT OPEN

E3 x In su ffi ci en t con d itio ned ai r ov er th e h eat ex ch an g er . B loc ke d filter s, re str ic tive duc twor k , im proper ci rc u lat or b low er sp ee d, or fa ile d c irc ul at or b low er m o tor. x Flam e rollout. x Mis al igne d bur ner s, b loc ke d f lue an d/ or a ir i n le t pi pe, or fa ile d in d u ce d dr aft bl ow er. x Loose or im properly conne cte d w iri ng. x Chec k f il ter s an d duc tw or k fo r bl oc ka ge. Cle an f il te rs or rem ove ob st ru ct io n. x Ch eck ci rcu lato r blower s p eed an d per form ance. Correct spee d or re place blower m o tor if nece ss ary . x Chec k b u rn er s f o r pr op er al ign m en t. x Chec k f lue a n d ai r i n le t p ipi ng fo r blo ck ag e, p rop er leng th , elb ow s, a n d te rm inati on. C o rrec t as nece ssa ry . x Chec k i n du ce d dra ft bl ow er f o r prope r per form ance. Replace if nece ss ary . x Tighte n or c o rrec t wiring co nne ct ion. x T u rn pow er O F F pr io r to repa ir. x See Spe cif ica ti o n S h ee t ap pl ica bl e t o y o ur m o del for a llowa ble r ise ra nge an d pr o p er c irc ula to r spe ed. x See "V en t/F lue P ipe " se ct ion fo r p ipi ng d etai ls . u ce d draf t b low er an d cir cu la tor b low er co nti nuo usl y . N o fu rn ace op erati on . egr ate d c o ntr o l m o du le L E D di sp lay des E4 err o r code. fortNet™ therm o st at “ C all for on illum inate d. fortNet™ therm os ta t scr o lls “ C heck nace” m essa ge.

E4

x Flam e sensed with no call for hea t. IMPROPE R FLAME E4 x Sh ort t o g ro u nd in fl ame s en se circ uit. x Linger ing bur ner f la m e. x Slow c lo sin g g as va lv e. x Corre ct shor t at f lam e sens or or in f lam e sensor wiring. x Chec k f o r linger ing f la m e. x Veri fy p rop er op eratio n o f gas val v e. x T u rn pow er O F F pr io r to repa ir. n ac e opera tion. egr ate d c o ntr o l m o du le L E D di sp lay des E5 err o r code. fortNet™ therm os ta t dis p lay s attery Power”.

E5

x Op en Fus e No t Di sp la y ed No t Disp la y ed x Sho rt in low vo lt ag e w iri ng x Locate and co rre ct short in low v o lt age wi ri ng x T u rn pow er O F F pr io r to repa ir. x Replace f u se with 3-a m p aut o m o ti ve ty pe al furna ce oper ation. egr ate d c o ntr o l m o du le L E D di sp lay des E6 err o r code.

E6

x Flam e sens e m icro am p si g n al is low WE A K FLAME E6 x Flam e sens or is c o at ed /o xi di ze d. x Flam e sens or inc o rr ec tly po si ti o n ed i n bur n er f lam e. x Lazy burner f lam e due to im proper ga s pr es su re or com bus tion air. x Sand flam e sensor if co at ed /ox id ized . x In sp ect fo r prop er se ns o r al ign m en t. x Ch eck inl et ai r p ipi ng fo r bl oc ka ge, pr o p er len g th, e lb o w s, an d term ina ti o n . x Com p are curr ent gas pre ss ure to rati ng pl at e. Ad jus t as n eed ed . x T u rn pow er O F F pr io r to repa ir. x Sand flam e sensor with e m ery cloth. x See " V ent/ Flu e Pi pe" se ct ion fo r p ipi ng d etai ls . x See rat ing pl ate fo r pr op er gas pre ssur e. nace fa ils to opera te. egr ate d c o ntr o l m o du le L E D di sp lay des E7 err o r code. fortNet™ therm o st at “ C all for on illum inate d. fortNet™ therm os ta t scr o lls “ C heck nace” m essa ge.

E7

x Pro b lem w ith ig ni ter circ uit. IGNITER FAULT E7 x Im pro p er ly conne cte d i g n iter. x Sho rte d ig ni ter. x Po or un it groun d . x Ign iter re lay faul t o n in te gra te d co ntr o l m odule. x Chec k a nd c o rr ect w irin g fr om in te gra te d co n tro l m odu le to ig n iter. x Repl ace s h o rt ed ig niter. x Ch eck an d co rrect uni t g round wi ri n g . x Ch eck ign it er o u tp ut fro m contr o l. Replace if necessary . x T u rn pow er O F F pr io r to repa ir. x Replace ignite r with corre ct re placem ent part. x Replace c o ntr o l with corre ct re placem ent part.

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T

ROUBLESHOOTING

C

HART

Co m fo r tNet™ Therm ost at On ly Sym ptom s of A bnor m al Opera ti on (Leg ac y & C o m fort N et™ Therm ost at) D ia g no st ic /St atus LED Codes Fault De scr ipt ion Messa ge Code P o ss ib le C a u se s Correct ive Action s No tes & Ca utio ns x Fur nace fa ils to opera te on high stage; fur nace opera tes nor m ally on low stage. x Int egr ate d c o ntr o l m o du le L E D di sp lay p rovi des E8 err o r code.

E8

x Hi gh st ag e p ressu re sw it ch c irc u it is c lose d at sta rt of heating cy cle. x In du ced d raft blo wer i s op era ti ng. x Fur nace is opera ting on low s ta g e on ly P S2 CLOSED E8 x Hi gh st ag e p ressu re swi tc h con tacts st ickin g . x Sh orts in pressu re s w it ch ci rcu it w iri ng. x Replace high sta g e pr essure sw it ch. x Repa ir s h or t i n w ir in g x T u rn pow er O FF pr io r to repa ir. x Replace pre ssure switch with cor rec t re pla cem ent par t. x Fur nace fa ils to opera te on high stage; fur nace opera tes nor m ally on low stage. x Int egr ate d c o ntr o l m o du le L E D di sp lay p rovi des E9 err o r code.

E9

x Hi gh st ag e p ressu re sw it ch ci rc u it is no t close d. x In du ced d raft blo wer i s op era ti ng. x Fur nace is opera ting on low s ta g e on ly PS 2 OPEN E9 x Pres su re sw it ch h o se bl oc ke d pi nc he d, or c o nne cte d im proper ly . x Bl ocked fl ue and/ o r in le t ai r pip e, bl oc ke d dr ai n sy stem or w ea k in d u ce d dr aft bl ow er. x Inc orrec t pre ssure switc h set p oin t o r m al fu n cti onin g s w it ch conta cts. x Loose or im properly conne cte d w iri ng. x In sp ect p res su re s w itch hos e. Repa ir /re pla ce if nec essa ry . x Ins pe ct f lu e an d /or in let a ir p ipi ng fo r bl ockag e, p rop er len g th, e lbow s, an d te rm inat ion. Chec k drain sy stem . Corre ct as nece ss ary . x Chec k i n d u ce d dra ft bl ow er perf orm ance. Corr ect as nece ss ary . x Co rrect p res su re s w itch set p oin t or c o n tac t m o tio n. x Tighte n or c o rrec t wiring co nne ct ion. x T u rn pow er O FF pr io r to repa ir. x Replace pre ssure switch with cor rec t replac em ent par t. x Replace induce d draf t blower with corr ec t replacem ent part. x Fur nace fa ils to opera te. x Int egr ate d c o ntr o l m o du le L E D di sp lay p rovi des EA err o r code. x Com fortNet™ therm os ta t “ C all for Service” ic on illum inate d. x Com fortNet™ therm os ta t scr o lls “ C heck Fur nace” m essa ge.

EA

x Pol ari ty of 11 5 vo lt A C is re ver se d REVERS ED PLTY EA x Pol ari ty of 11 5 vo lt A C pow er to fur nace or in te g rat ed m odule is rever ed. x Po or un it groun d x Revi ew wi ri ng di ag ram t o corre ct polar it y . x Veri fy p rop er groun d. Co rrect i f nece ss ary . x Chec k a nd c o rr ect w irin g. x T u rn pow er O FF pr io r to repa ir. x Fur nace fa ils to opera te. x Int egr ate d c o ntr o l m o du le L E D di sp lay p rovi des d 0 err o r c o de. x Com fortNet™ therm os ta t “ C all for Service” ic on illum inate d. x Com fortNet™ therm os ta t scr o lls “ C heck Fur nace” m essa ge.

d0

x D ata n o t y et on netw ork. NO NET DATA d0 x Fur

nace does not

co ntain an y sh ar ed d at a. x Po pul at e sh ared d ata s et us in g m e m o ry card. x T u rn pow er O FF pr io r to repa ir x Use m e m o ry card for the spe cif ic m odel. x Insert m e m o ry card BEFORE t u rn ing power O N . Mem ory card m ay be rem oved af ter dat a i s loa de d. x T u rn pow er O FF bef ore rem oving m e m o ry ca rd. x Error c ode w ill be cle ared once data is loaded.

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T

ROUBLESHOOTING

C

HART

Co m fo r tNet™ Therm ost at On ly ptom s of A bnor m al Opera ti on ac y & C o m fort N et™ Therm ost at) D ia g no st ic /St atus LED Codes Fault De scr ipt ion Messa ge Code P o ss ib le C a u se s Correct ive Action s No tes & Ca utio ns erat ion di fferent than ex pected o r no era ti on. egr ate d c o ntr o l m o du le L E D di sp lay des d 4 err o r c o de. fortNet™ therm os ta t “ C all for on illum inate d. fortNet™ therm os ta t scr o lls “ C heck nace” m essa ge.

d4

x In valid m e m o ry card dat a. INVALID MC DATA d4 x Share d data se t on m e m o ry card has bee n rej ec te d by inte gr ate d co ntr o l m odule x Verify share d data se t is c o rrec t for the specific m ode l. Re-po p u la te da ta u sin g c o rrec t m e m o ry card if re quired. x T u rn pow er O FF pr io r to repa ir x Use m e m o ry card for the spe cif ic m odel. x Insert m e m o ry card BEFORE t u rn ing power O N . Mem ory card m ay be rem oved af ter dat a i s loa de d. x T u rn pow er O FF bef ore rem oving m e m o ry ca rd. x Error c ode w ill be cle ared once data is loaded. nace fa ils to opera te. egr ate d c o ntr o l m o du le L E D di sp lay des b 0 err o r c o de. fortNet™ therm os ta t “ C all for on illum inate d. fortNet™ therm os ta t scr o lls “ C heck nace” m essa ge.

b0

x Circ ul at or bl ow er m o tor is n o t ru nni ng wh en it shou ld be runn ing .

MOTOR _{NOT RUN}

b0 x L o o se w ir in g c o nne ct io n a t circ ul at or m o tor pow er lea d s or circ ul at or m o tor pow er lea d s di sc on ne cte d. x Op en ci rcui t i n i ndu cto r o r lo os e wi rin g con nect io n at in du ct or (3/4 H p an d 1 H p m odels on ly ). x Fail ed ci rcul ato r b lower m o to r. x Tighte n or c o rrec t wiring co nne ct ion. x Veri fy co nt in uou s ci rcu it thr o u g h in d u ct or. Re pla ce if op en or s h ort c irc u it. x Ch eck ci rcu lato r blower m o to r. Replace if nece ssa ry . x T u rn pow er O F F pr io r to repa ir x Replace induc tor w ith corre ct re placem ent part. x Replace c irc ulator m o tor with cor rec t re pla cem ent par t. nace fa ils to opera te. egr ate d c o ntr o l m o du le L E D di sp lay des b 1 err o r c o de. fortNet™ therm os ta t “ C all for on illum inate d. fortNet™ therm os ta t scr o lls “ C heck nace” m essa ge.

b1

x Int egr ate d c o ntr o l m odule has lo st co mm u n icatio ns wit h circ ul at or bl ow er m o tor. MOTOR COMM b1 x L o o se w ir in g c o nne ct io n a t circ ul at or m o tor c o nt rol lea d s. x Fail ed ci rcul ato r b lower m o to r. x Fail ed i n te g rat ed co ntro l m o du le . x Tighte n or c o rrec t wiring co nne ct ion. x Ch eck ci rcu lato r blower m o to r. Replace if nece ssa ry . x Ch eck int eg rated cont rol m o d u le . Replace if nece ssa ry . x T u rn pow er O F F pr io r to repa ir x Replace c irc ulator m o tor with cor rec t re pla cem ent par t. x Replace inte gra te d contr o l m odule w ith cor rec t replacem ent part. nace fa ils to opera te. egr ate d c o ntr o l m o du le L E D di sp lay des b 2 err o r c o de. fortNet™ therm os ta t “ C all for on illum inate d. fortNet™ therm os ta t scr o lls “ C heck nace” m essa ge.

b2

x Circ ul at or bl ow er m o tor hor se pow er i n s h are d d ata s et do es not m at ch circ ul at or bl ow er m o tor hor se pow er . MOTOR MIS M ATCH b2 x Inc orrec t c irc ulator blower m o tor in f u rn ace. x Inc orrec t sh ar ed da ta set in in te gra te d co n tro l m odu le. x Verify circula tor blower m o tor hor se pow er i s t h e s am e spe cif ie d f o r the s p ec ific fur nac e m odel. Replace if necessary . x Verify share d data se t is c o rrec t for the specific m ode l. Re-po p u la te da ta u sin g c o rrec t m e m o ry card if re quired. x T u rn pow er O F F pr io r to repa ir x Replace m o tor w ith c o rrec t replacem ent part. x Use m e m o ry card for the spe cif ic m odel x Insert m e m o ry card BEFORE t u rn ing power O N . Mem ory card m ay be rem oved af ter dat a i s loa de d. x T u rn pow er O FF bef ore re mo v in g me mo ry c a rd . x Error c ode w ill be cle ared once share d data and m o tor horse power m atc h. nace opera tes a t r educe d pe rform ance. ow de li ve red is l ess t h an ex pec te d. egr ate d c o ntr o l m o du le L E D di sp lay des b 3 err o r c o de.

b3

x Circ ul at or bl ow er m o tor is op era ti ng i n a p o w er, tem perature, or spee d li m it ing cond it ion . MOTOR LIMITS b3 x Bl ocked fi lt ers . x Restrictive duc twor k. x Un d ersi ze d du ct wo rk. x High am bient tem per atures. x Chec k f il ter s for b loc ka ge. Clea n fi lt er s or rem ove ob st ru ct io n. x Chec k d u ct w o rk f o r b loc ka ge. Rem ove ob st ru ct io n. V erify all regis ter s are f u lly ope n. x V erify duc tw or k i s ap pro pr ia te ly siz ed f o r sy stem . Resize /re pla ce ductw ork if nece ss ar y . x See "P rodu ct Des cr ipt ion" an d "L oc at ion R equ ir em en ts & Con si dera tio ns" f o r f u rnace in st all at ion requi rem en ts . x T u rn pow er O FF pr io r to repa ir.

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T

ROUBLESHOOTING

C

HART

Co m fo r tNet™ Therm ost at On ly Sym ptom s of A bnor m al Opera ti on (Leg ac y & C o m fort N et™ Therm ost at) D ia g no st ic /St atus LED Codes Fault De scr ipt ion Messa ge Code P o ss ib le C a u se s Correct ive Action s No tes & Ca utio ns x Fur nace fa ils to opera te. x Int egr ate d c o ntr o l m o du le L E D di sp lay p rovi des b 4 err o r c o de. x Com fortNet™ therm os ta t “ C all for Service” ic on illum inate d. x Com fortNet™ therm os ta t scr o lls “ C heck Fur nace” m essa ge.

b4

x Circ ul at or bl ow er m o tor se ns es a los s o f ro to r contr o l. x Circ ul at or bl ow er m o tor se ns es hig h cu rrent . MOTOR TRIPS b4 x A b n o rm al m o tor loa d in g , su dde n ch an ge in sp eed or torq ue, su dd en bl oc ka ge o f fur nac e a ir i n le t or o utl et . x Hi gh lo ad ing cond it io ns , blo cked filter s, ve ry rest rictive ductw ork, bl oc ka ge o f fur nac e a ir i n le t or o utl et . x Chec k f ilter s, filte r gri ll s/ re gi st er s, d u ct sy stem , and fur nace a ir inle t/outle t for bl oc ka ge s. x T u rn pow er O FF pr io r to repa ir. x Fur nace fa ils to opera te. x Int egr ate d c o ntr o l m o du le L E D di sp lay p rovi des b 5 err o r c o de. x Com fortNet™ therm os ta t “ C all for Service” ic on illum inate d. x Com fortNet™ therm os ta t scr o lls “ C heck Fur nace” m essa ge.

b5

x Circ ul at or bl ow er m o tor fai ls to sta rt 10 conse cutive tim es. MTR LCKD ROTOR b5 x O b st ru ct io n in ci rc u la tor bl ow er h ous ing . x Sei zed ci rcu lato r blower m o to r b earin gs . x Fail ed ci rcul ato r b lower m o to r. x Ch eck ci rcu lato r blower fo r ob st ru ct io n s. Rem ove an d repa ir /re pla ce w h ee l/ m otor if nece ss ary . x Ch eck ci rcu lato r blower m o to r sha ft r o ta ti on a n d m o tor. Replace m o tor if nec ess ary . x T u rn pow er O FF pr io r to repa ir x Replace m o tor w ith c o rrec t replacem ent part. x Replace w h ee l with c o rrec t replacem ent part. x Fur nace fa ils to opera te. x Int egr ate d c o ntr o l m o du le L E D di sp lay p rovi des b 6 err o r c o de. x Com fortNet™ therm os ta t “ C all for Service” ic on illum inate d. x Com fortNet™ therm os ta t scr o lls “ C heck Fur nace” m essa ge.

b6

x Circ ul at or bl ow er m o tor shut s d o w n for ov er or u n d er vo lt ag e co nd itio n . x Circ ul at or bl ow er m o tor sh u ts dow n d u e to ov er te m p eratu re co ndi ti on on pow er m o d u le. MOTOR VOLTS b6 x High AC line vo lta ge to f u rn ace. x

Low AC line volta

ge to f u rn ace. x High am bient tem per atures. x Chec k power to f u rn ace. Verify li n e v o lt age to fu rn ace i s with in the r ange specifie d on the fur nace r ating pla te. x See "P rodu ct Des cr ipt ion" and "L oc at ion R equ ir em en ts & Con si dera tio ns" f o r f u rnace in st all at ion requi rem en ts . x T u rn pow er O FF pr io r to repa ir. x Fur nace fa ils to opera te. x Int egr ate d c o ntr o l m o du le L E D di sp lay p rovi des b 7 err o r c o de. x Com fortNet™ therm os ta t “ C all for Service” ic on illum inate d. x Com fortNet™ therm os ta t scr o lls “ C heck Fur nace” m essa ge.

b7

x Circ ul at or bl ow er m o tor d o es n o t have enou gh inf orm ation to opera te pro pe rly . x Mo tor fa il s to st art 4 0 conse cutive tim es. MOTOR PARAMS b7 x E rror w ith in te gra te d co ntr o l m odule. x M o to r h as a lo ck ed ro to r co nd it ion. x Ch eck int eg rated cont rol m o d u le . Veri fy co nt rol is popu la te d wit h corre ct share d da ta se t. See da ta erro rs ab ov e fo r d etail s. x Ch eck fo r lo ck ed rotor con di tio n (see er ror c o de a b ove for d etail s). x T u rn pow er O FF pr io r to repa ir. x

Replace with correc

t replacem ent part(s). x Use m e m o ry card for the spe cif ic m odel. x Fur nace opera tes a t r educe d pe rform ance or oper ate s on low stag e when high sta g e is expec ted. x Int egr ate d c o ntr o l m o du le L E D di sp lay p rovi des b 9 err o r c o de.

b9

x Ai rflo w is lo wer th an dem ande d. LOW I D AIRFLO W b9 x Bl ocked fi lt ers . x Restrictive duc twor k. x Un d ersi ze d du ct wo rk. x Chec k f il ter s for b loc ka ge. Clea n fi lt er s or rem ove ob st ru ct io n. x Chec k d u ct w o rk f o r b loc ka ge. Rem ove ob st ru ct io n. V erify all regis ter s are f u lly ope n. x V erify duc tw or k i s ap pro pr ia te ly siz ed f o r sy stem . Resize /re pla ce ductw ork if nece ss ar y . x T u rn pow er O FF pr io r to repa ir.

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S

TATUS

C

ODES

C 2

O P

H I

b 0

d 4

C 1

b 2

E 4

H I

INTERNAL CONTROL FAULT/NO POWER

NORMAL OPERATION

LOCKOUT DUE TO EXCESSIVE RETRIES

LOW STAGE PRESSUE SWITCH STUCK CLOSED AT START OF HEATING CYCLE LOW STAGE PRSSURE SWITCH STUCK OPEN

OPEN HIGH LIMIT SWITCH

FLAME DETECTED WHEN NO FLAME SHOULD BE PRESENT OPEN FUSE

LOW FLAME SIGNAL

IGNITER FAULT OR IMPROPER GROUNDING

HIGH STAGE PRESSURE SWITCH STUCK CLOSED AT START OF HEATING CYCLE HIGH STAGE PRSSURE SWITCH STUCK OPEN

REVERSED 115 VAC POLARITY DATA NOT YET ON NETWORK INVALID MEMORY CARD DATA BLOWER MOTOR NOT RUNNING BLOWER COMMUNICATION ERROR BLOWER HP MIS-MATCH

BLOWER MOTOR OPERATING IN POWER, TEMPERATURE, OR SPEED LIMIT BLOWER MOTOR CURRENT TRIP OR LOST ROTOR

BLOWER MOTOR LOCKED ROTOR

OVER/UNDER VOLTAGE TRIP OR OVER TEMPERATURE TRIP INCOMPLETE PARAMETERS SENT TO MOTOR