78
PHTM II
Combi Installation, Operating & Service Instructions
110331-07 - 8/23
19
Troubleshooting
(continued)
D. Troubleshooting with Active Fault Code.
Control uses following codes to describe abnormal operation:
Table 19-4: Lockout/Hold/Warning Symbol Description
Code
Type
Boiler Status
Description
E
Lockout
Shutdown
When a lockout occurs, boiler will shut down and event is stored in
history,
b
, menu. Once condition that caused lockout is corrected,
boiler remains shut down until a reset has been performed by pressing
!
reset
button.
H
Hold
Shutdown
When a hold occurs, boiler will shut down. Event is stored in history,
b
,
menu. Boiler will automatically restart once condition that caused hold is
corrected.
Warning
Free to operate
When a warning occurs, an abnormal condition has affected boiler
operation and event is stored in history,
b
, menu. Boiler continues to
operate.
Table 19-5: Active Fault Code and Corrective Actions
Detailed Fault Code found on "
b
" and "
c
" menus in brackets, e.g. [
1
.
0
].
Code/
Name
Possible Cause
Corrective Action
H01
Anti-
Short
Cycle
[
01
.
0
] While thermostat demand
present, boiler has cycled off too
quickly due to temperature and
restart is delayed.
Boiler will restart automatically after the minimum off time (Anti-
Short Cycle Time, default 3 min.).
[
01
.
1
] Urgent calibration demand
present, waiting for supply
temperature to decrease.
Boiler will start after supply temperature drops below 95°F (35°C).
Low supply temperature helps to ensure a successful calibration.
No action is necessary.
H02
Safety
Limit
Open
External limit is open.
• If not using an external limit, check jumper is installed
according to wiring diagram.
• If using an external water temperature limit see
H04
/
E04
for
corrective action.
• Verify external limit setting.
• Check external limit wiring to boiler, correct if necessary.
LWCO, low water condition.
• If not using a LWCO, check jumper is installed according to
wiring diagram.
• Check LWCO indicators.
If yellow light "On":
-Verify that system is full of water and all air has been properly
purged. Cycle boiler power to initiate pump air elimination
function.
-Check automatic air vent is unobstructed and properly
functioning, (blocked air vent can result in low water condition).
If yellow and green light "Off", check LWCO wiring harness.
Thermal fuse is open.
Check thermal fuse for continuity. If "open", consult manufacturer.
