73
110331-07 - 8/23
PHTM II
Combi Installation, Operating & Service Instructions
19
Troubleshooting
WARNING
Electrical Shock Hazard.
Turn off power to boiler before working on wiring.
!
A. Troubleshooting with No Active Fault Code Displayed
Table 19-1: 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, 5x20 mm if necessary.
Loose blower wiring.
Check blower wiring connections, correct if
necessary.
Defective control.
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.
Check remote thermostat setting.
Loose thermostat wiring.
Check thermostat wiring, correct if necessary.
Blown T0.5A Fuse (supplies power
to thermostats).
Check T0.5 A Fuse, replace with a 0.5 Amp, 250V,
Slow Blow, 5x20 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 available with PAT-Connect Bluetooth Adaptor
and App.
No Central Heat,
Boiler Runs
Defective 3-way valve.
Check 3-way valve, replace if necessary.
Defective 3-way valve wiring.
Check wiring to 3-way valve, correct if necessary.
Recirculation piping problem.
Recirculation sensor does not detect flow. Check
piping. See Figure 11-3.
Boiler Running But
System Or Auxiliary
Pump Not Running
Pump setting is incorrect.
Switch
PU
Menu Item
P01
, System Pump Selection.
Refer to Table 16-15.
Loose wiring to pump
Check pump wiring, correct if necessary.
Defective pump.
Replace pump.
