Paloma PH2-20R OFN, Engineering Handbook

Page: 83 / 172

SVC 820-Tankless Gas Trouble Shooting Manual Page | 83
83
72 – Error Code Diagnostic Chart
NO
Clean or Replace Flame
Rod(s)
Water heater appears
to be normal.
Attempt to operate
again
YES
NO
YES
NO
Turn power OFF. Unplug unit and plug
back in. Turn power ON. While viewing
burner chamber through sight glass, turn
on water flow to begin ignition sequence
Is there a visible
flame before
Igniter Rod
sparks?
Visibly inspect burner chamber through
sight glass
Is debris visible
on burner
assembly?
YES
Remove and clean burner assembly
NO
Turn power OFF. Unplug unit. Disconnect
Molex connector(s) from Flame Rod(s).
Plug unit in. Turn power ON. Turn water
flow ON to begin ignition sequence
Does ‘OY’ Status in
Maintenance Mode
indicate presence
of flame?
Does ‘OY’ Status in
Maintenance Mode
indicate presence
of flame?
YES
Attempt to operate again.
If unit displays 72 Error Code:
Replace Control Board
On Remote Control, go to Maintenance Mode 0Y table. For Maintenance Mode
instructions go to page 16.
All Maintenance Mode ‘0Y’ readings should be done immediately after turning
the unit ON. IF flame sensor IS detecting flame, Maintenance Mode will display:
Indoor Units: 05
Outdoor Units: 01
Attempt to operate again. If unit displays 72
Error Code and flame IS visible while unit is OFF:
Replace Gas Control Valve