Paloma PH2-20R OFN Engineering Handbook page 55

Check the resistance across 2 black wires
on bottom Molex:
7k – 23K Ohms
SVC 820-Tankless Gas Trouble Shooting Manual
16 – Error Code Diagnostic Chart
Is the resistance
to the Outlet
Thermistor OK?
YES
Remove Molex from connector "R" at Control Board.
Check continuity from black #3 wire at Molex
connector "R" and black wires on black Molex located
behind Control Board. Check continuity from red #4
wire at Molex connector "R" and red wire on black
Molex located behind Control Board
Is the continuity
across all wires
OK?
YES
Attempt to operate unit again.
If the unit malfunctions due to an Error Code 16:
Go to Error Code 66 for Water Bypass Valve
diagnostics
Clean Outlet Thermistor. Retest
Thermistor. IF tests OK, the water heater
appears to be normal, attempt to operate
NO
unit again. IF resistance NOT OK:
Replace Outlet Thermistor
Replace wiring harness for connector "R"
on Control Board
NO
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