70
110332-02 - 6/22
PHTM II
Installation, Operating & Service Instructions
18
Troubleshooting
WARNING
Electrical Shock Hazard.
Turn off power to boiler before working on wiring.
!
A. Troubleshooting with No Active Fault Code Displayed
Table 18-1: Troubleshooting with No Active Fault Code
Indication
Possible Causes
Corrective Action
Display Completely
Dark And Fan Off
No 120 VAC supplied to boiler.
Check breaker and wiring between breaker panel and
boiler.
Display Completely
Dark, Fan Running
Blown T1.0 A Fuses (supplies power
to control).
Check T1.0 A Fuse, replace with a 1 Amp, 250V, Slow
Blow, 5 x 20 mm if necessary.
Loose low voltage blower wiring.
Check low voltage blower wiring connections.
Control damaged.
Replace control.
Boiler Not
Responding To
Call For Heat,
Icon Is Off
A01
Boiler On/Off Switch is "Off",
(Status
StA13
).
Switch Quick Menu Item
A01
, Boiler On/Off Switch,
"On".
Remote thermostat is satisfied, loose
thermostat wiring.
Check remote thermostat setting and wiring.
Blown T0.5 A Fuse (supplies power
to thermostats).
Check T0.5 A Fuse, replace with a 0.5 Amp, 250V,
Slow Blow, 5 x 20 mm if necessary.
Boiler Not
Responding to Call
For Heat,
Icon is On
Boiler is in standby, (Status
StA 1
),
temperature is above setpoint.
Check temperature setpoint setting.
Faucet icon is on
Servicing DHW demand.
Boiler is in Warm Weather Shutdown,
(Status
StA 14
).
Feature not available with local user display.
Boiler Running But
System Or Auxiliary
Pump Not Running
Pump setting is incorrect.
Switch
PU
Menu Item
P01
, System Pump Selection.
Refer to Table 15-15.
Loose wiring to pump
Check pump wiring.
Pump damaged.
Replace pump.
Boiling, Kettling, or
Water Hammer
Air in system piping.
Cycle power to boiler to initiate an air elimination
cycle to help remove air from boiler water.
Low system water pressure.
Check boiler water pressure, adjust feedwater as
required.
Rough ignitions
Gas pressure problem.
Refer to Table 3-4 for required pressure range.
Dirty/damaged burner.
Refer to Section 17 Service and maintenance for
proper procedure to check burner. Replace if
necessary.
Dirty/damaged ignitor/flame sensor.
Refer to Section 17 Service and Maintenance for
proper procedure to check ignitor/flame sensor.
• Check spark gap and ignitor/flame sensor distance
to burner. Replace if necessary.
Relief Valve
Opening
System pressure exceeds relief
valve setting.
Lower system pressure below rating of supplied
safety relief valve.
Replace standard safety relief valve with higher
rated valve up to the maximum pressure of the heat
exchanger. 50 psig (345 kPa)
Improperly sized expansion tank.
