84
PHTM II
Combi Installation, Operating & Service Instructions
110331-07 - 8/23
19
Troubleshooting
(continued)
Code/
Name
Possible Cause
Corrective Action
H24
E24
Flame Loss
During Run
No gas, insufficient gas
supply pressure.
• Verify no air in gas line.
• Check gas valve inlet pressure while boiler off and during operation.
The boiler has not started
due to high winds.
The control automatically raised the minimum capacity value to help
prevent high wind from preventing ignition again. Minimum capacity is
returned to normal after one hour.
Air flow is blocked.
• Check vent and air inlet for blockage. Remove blockage.
• Check heat exchanger for excessive fouling. Clean if necessary.
• Check integrity of burner. Replace burner (including burner door) if
necessary.
Dirty or damaged ignitor/
flame sensor.
Check ignitor/flame sensor gap and distance to burner. See Figure 18-2
and Table 18-3 for distance specifications. Replace ignitor/Flame sensor
if necessary.
Defective burner.
Check integrity of burner. Replace burner (including burner door) if
necessary.
Blocked condensate trap.
Check the condensate trap and clean if necessary.
Fuel Gas Selection,
(parameter
A06
), Altitude
Selection (parameter
A07
)
or gas valve setting is
incorrect.
Check Fuel Gas Selection, parameter
A06
, and gas valve setting (Figure
15-3). Both selections must be set to same fuel type. Also, check Altitude
Selection (parameter
A07
) is correct for installation elevation.
Turndown too high.
Reduce turndown by increasing
F06
Minimum Capacity.
H25
E25
Hardware
Fault
Defective control.
Replace control.
H26
E26
Calibration
Fault
[
26
.
0
] Too long running at
calibration without going to
minimum capacity.
Cycle power to initiate calibration.
[
26
.
1
], [
26
.
2
], [
26
.
3
]
Calibration has not been
possible.
• Resolve issue preventing boiler from running for approximately 1.5
minutes during calibration demand [
StA
=
5
].
• Cycle power to initiate a calibration.
H27
120 VAC
Supply
Fault
120 VAC supply voltage
less then 73 VAC.
Check 120 VAC supply, correct issue.
H28
24 VAC
Supply
Fault
Control 24 VAC wrong
frequency.
Check 120 VAC supply, correct issue.
Defective control.
Replace control.
E29
Excessive
Reset
Selection
Control
!
reset
button has
been selected too often.
To clear, cycle power to control and press
!
reset
button above local display.
Table 19-5: Active Fault Code and Corrective Actions (continued)
Detailed Fault Code found on "
b
" and "
c
" menus in brackets, e.g. [
1
.
0
].
