Rinnai REU-VR3237WG Service Manual page 29

Water Flow Servo Circuit
9.
a.) Disconnect relay connector (G
Water Flow Servo.

Normal: 10~30
If normal, proceed to b.
Faulty: Replace Water Flow Servo and Water Flow Sensor.
b.) Disconnect relay connector (G
(-) on PCB unit side.
Normal: DC11~13V
If normal: proceed to c).
Faulty: Replace PCB unit.
c.) Measure voltage between Brown and Grey with relay connector (G
no water flowing, water flow servo fully open).
Normal: DC4~6V
Faulty: Replace Water Flow Servo with Water Flow Servo.
d.) Measure voltage between Yellow and Grey with relay connector (G
no water flowing, water flow servo fully open).
Normal: < DC1.0V
Faulty: Replace Water Flow Servo and Water Flow Sensor.
10. Heat Exchanger Outlet Thermistor Circuit (G
Check Heat Exchanger Outlet Thermistor if error indicator "33" is displayed.

Disconnect relay connector (G
Circuit Break: Resistance > 1M
Short Circuit: Resistance < 1
If normal, proceed to Water Flow Servo Circuit
If faulty, replace Heat Exchanger Outlet Thermistor.
Note: For controller readout of thermistor temperature whilst operational refer
maintenance monitor (chapter 17) No. 11.
Infinity REU-VRM3237WG / HD250e REU-VRM3237WC
(G )
6
), and measure resistance between Red and Blue of
6
), and measure voltage between Orange (+) and Grey 
6
)
4
) and measure resistance between White and Pink.
4


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) connected (with
6
) connected (with
6
Issue 1 - 19/05/09 ©Rinnai