Paloma PH2-20R DVSN, Engineering Handbook

Page: 71 / 172

SVC 820-Tankless Gas Trouble Shooting Manual Page | 71
71
51 – Error Code Diagnostic Chart
NO
Clean or Replace Flame
Rod(s)
Water heater appears
to be normal.
Attempt to operate unit
again
YES
NO
YES
NO
While viewing burner chamber through
sight glass:
In 10 second intervals; cycle the water
heater 3 times by turning unit
“on – off; on – off; on – off”
Is there a visible
flame while unit
is OFF?
Visibly inspect burner chamber through
Sight Glass
Is debris visible
on burner
assembly?
YES
Remove and clean burner assembly
NO
Disconnect Molex Connector from Flame
Rods(s). Cycle the water heater 3 times by
turning unit “on – off; on – off; on – off”
Does ‘OY’ Status in
Maintenance Mode
indicate presence
of flame after 5
seconds?
Does ‘OY’ Status in
Maintenance Mode
indicate presence
of flame after 5
seconds?
YES
Attempt to operate unit again. If the unit
malfunctions due to an Error Code 51:
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 OFF. IF Flame Rod(s) is
detecting flame, Maintenance Mode will display:
Indoor Units: 05
Outdoor Units: 01
Attempt to operate unit again. If the unit
displays 51 Error Code and flame IS visible while
unit is OFF:
Replace Gas Control Valve