Rinnai RUC80i Training Program page 54

Electrical Diagnostics:
1. Measure incoming voltage:
a. Check power at receptacle or circuit breaker.
b. Check power to PCB, connector F, pins #1 and #3, black
and white wires. (not shown).
c. Check fuse mounted on PCB.
2. Measure continuity of safety circuit:
a. Test the thermal fuse circuit between white wire on
connector B7 and white wire on connector B8.
b. Check burner overheat switches (OH#2) from the white
wire to the red wire on connector B7.
c. Check the secondary heat exchanger overheat switches
(OH#3) between the red wires on connector B6.
3. Measure resistance of gas solenoid valves:
a. SV1 (con. B3, black/blue), SV2 (con. B2, black/yellow),
SV3 (con. 4, black/red).
b. Modulating solenoid valve (POV) (yellow/yellow).
4. Measure resistance of heat exchanger thermistor (con. E5) OR
inlet water temperature thermistor (con. E9).
➢ NOTE: Compare reading to temperature range listed on
tech sheet or service manual.
➢ Hold thermistor bulb in your hand and note the change
in reading.
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PROPRIETARY and CONFIDENTIAL
Enhancing Lives By Changing The Way Water Is Heated
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