Rinnai REU-VR3237WG Service Manual page 28

7. Thermal Fuse
Overheat switch and thermal fuse circuit
1. Disconnect overheat switch terminals (G
switch terminals (G

Normal: < 1
If not normal replace overheat switch.
If normal reconnect overheat switch terminals (G
2. Disconnect relay connectors G
red wires.

Normal: < 1
If not normal replace thermal fuse.
If normal replace PCB 
Note: If thermal fuse or overheat switch were faulty:
a) Check heater for damage.
b) Confirm gas type and combustion dipswitch settings.
c) Confirm test point pressure.
8. Water Flow Sensor (G
a.) Measure voltage between Red - Black of relay connector (G
Normal: DC 11~13V
If normal, proceed to b.
Faulty: Replace PCB.
b.) Measure voltage between Yellow - Black of relay connector (G
Normal: DC 4~7V
If normal, proceed to 2.
Faulty: Replace water flow sensor.
Note: For controller readout of water flow whilst operational refer maintenance monitor
(chapter 17.) No. 1)
Infinity REU-VRM3237WG / HD250e REU-VRM3237WC
).
2
and E and measure resistance between the white and
1 3
)
3
- 23 -
) and measure resistance between overheat
2
) and proceed to step 2.
2
).
3
).
3
Issue 1 - 19/05/09 ©Rinnai