N95ESN: Installation, Start-up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
64
A190092
Fig. 71 – Troubleshooting Guide (Cont)
1 + 2 BLOWER ON AFTER POWER UP –
(115V OR 24V) – Normal operation.
Blower runs for 90 seconds, if unit is
powered up during a call for heat (R-
W/W1 closed) or when (R-W/W1 opens)
during the blower on-delay period.
6 + 1 IGNITION LOCKOUT – System failed to
ignite gas and prove flame in 4
attempts. Control will auto-reset after 3
hours. Refer to status code #6.
5 ABNORMAL FLAME-PROVING SIGNAL
Flame is proved while gas valve is de-
energized. Inducer will run until fault is
cleared. Check for:
- Stuck open or leaky gas valve.
2 PRESSURE SWITCH DID NOT OPEN –
Check for:
- Obstructed pressure tube.
- Pressure switch stuck closed.
3 LPS PRESSURE SWITCH DID NOT
CLOSE OR REOPENED
– If LPS open
longer than five minutes, inducer shuts off
for 15 minutes before retry.
Check for:
- Excessive wind
- Proper vent sizing
- Defective inducer motor
- Low inducer voltage (115VAC)
- Defective pressure switch
- Inadequate combustion air supply
- Disconnected or obstructed pressure
tubing
- Low inlet gas pressure (if LGPS used)
- Restricted vent
- Condensate drainage restricted or
blocked.
If it opens during blower on-delay period,
blower will come on for the selected
blower off-delay.
4 LIMIT CIRCUIT FAULT – Indicates the
limit, flame rollout is open. Blower will run
for 4 min. or until open switch remakes
whichever is longer. If open longer than 3
min, code changes to lockout #7. If open
less than 3 min. status code #4 continues
to flash until blower shuts off. Flame
rollout switch requires manual reset.
Check for:
- Loose blower wheel.
- Defective switch or connections.
- Dirty filter or restricted duct system.
- Improper gas input adjustment
-
Improper limit switch or no limit gasket.
To determine whether the problem is in
the gas valve, igniter, or flame sensor the
system can be operated in component
test mode. To check the igniter, remove
the R thermostat connectio
n from the
control, reset power, start the component
test. Does the igniter glow orange/white
by the end of the 15 second warm
-up
period?
Unplug igniter harness from control and
repeat component test. Check for 115V
between connector P2 (HSI) and
NEUTRAL-L2 on the control. Was 115V
present for the 15 second period?
Check connections and retry.
If current is near typical value
(4.0
-
6.0μA DC nominal) and
burners will not stay on,
replace control.
Clean flame sensor with fine steel wool
and recheck current. Nominal current is
4.0 to 6.0
μA DC.
Is current near typical value?
Will main burners ignite and stay on?
Check for continuity in the
harness and igniter. Replace
defective component.
Reconnect the R thermostat lead and set
thermostat to call for heat. Connect
voltmeter across gas valve connections.
Does gas valve receive 24V?
Does gas valve open and allow gas to
flow?
Do the main burners ignite?
Do the main burners stay on?
Allow blower to come on and
repeat test to check for
intermittent operation.
Check that gas valve electric
switch is
turned on. Replace
valve.
Check connections. If OK,
replace control.
Check for:
- Inadequate flame carryover
or rough ignition.
- Low inlet gas pressure.
- Proper firing rate.
Repeat call for heat and check flame
sensor current during trial for ignition
period. Is the DC
current below 0.5μA
6 IGNITION PROVING FAILURE – If flame is
not sensed during the trial for ignition
period, the control will repeat the ignition
sequence 3 more times before lockout #6 +
1 occurs. If flame signal is lost during the
blower on-delay period, blower will come on
for the selected blower off-delay. Check
the following before going to the next step.
- Gas valve turned off .
- Manual shut-off valve open?
- Green/Yellow wire MUST be connected
to furnace sheet metal.
- Flame sensor must not be grounded.
10 POLARITY – Check for correct line
voltage polarity. If units are twinned,
check for proper low-voltage (24V)
transformer phasing.
7 LIMIT CIRCUIT LOCKOUT – Lockout
occurs if the limit, flame rollout is open
longer than 3 minutes. Control will auto-
reset after 3 hours. Refer to status code
#4.
8 GAS HEATING LOCKOUT – Control will
NOT auto r
eset. Turn off power and wait
5 minutes to retry. Check for:
-
Stuck closed gas valve relay on control.
- Miswire or short to gas valve wire.
9 HPS PRESSURE SWITCH DID NOT
CLOSE OR REOPENED
- If HPS remains
open for one minute after gas valve closes (after
three succesive trials), then furnace control will
lockout for 3 hours before retry. See Code 3 for
troubleshooting.
To Next Page
Loading...
