Rinnai REU-V1620WG Service Manual page 27

10. Water Flow Control Device Circuit
a) Disconnect relay connector (E
unit side (while operating).
Normal: DC11-13V
If normal: proceed to b.).
Faulty: Replace PCB unit.
b) Measure resistance between Yellow and Grey with relay connector (E
Normal: DC4~6V (Pulse 20~320Hz)
Faulty: Replace Water Flow Servo. If normal proceed to c).
c) Measure voltage between Brown and Grey with relay connector (G
Normal: DC4~6V
Faulty: Replace Water Flow Servo.
11. Thermistor Circuit
Check Thermistor if error code "32" is displayed.
Disconnect relay connector (E
When disconnected: resistance >1M
When short circuit: resistance < 1
Operating: Check Heat exchanger outlet thermistor
Resistance matches table below.
Faulty: Replace hot water outlet thermistor.
Normal
Temperature
15
k
Resistance
If normal proceed to Flame Rod circuit.
Faulty: Replace Thermistor.
Note: For controller readout of thermistor temperature whilst operational refer maintenance monitor.
12. Surge Protector (F
a) Check the electrical fuses between F
replace with fuses of the correct rating (240V, 3A). If okay, go to b).
b) Check supply voltage at F
voltage incorrect check power supply to appliance. If okay go to c).
c) Check voltage at F
If voltage is zero repeat a). If fuses are okay replace Surge Protector.
13. Anti-frost Heater Circuit
a) Disconnect relay connectors (F
valve frost heater at the frost heater side.

Normal: 53
If normal, proceed to b).
Faulty: Replace Valve Heater.
b) Disconnect relay connector (F
frost heater at the frost heat side.

Normal: 618
Faulty: Replace Anti-frost Heater.
14. Frost Sensing Switch
Disconnect relay connector (F
At room temperature resistance should be > 1 M
Cool switch to below 2° C then measure resistance.
Resistance should be < 1M
Faulty: Replace Frost Sensing Switch.
REU-V1620WG / REU-V1620WB / REU-V1620WS / REU-V2024WG - 22 -
), and measure voltage between Red (+) and Black (-) on PCB
5
) and/or (E ) and measure resistance White -White.
4 3


o o
C 30 C
6.4~7.8 k
)
1
and F
2
. Voltage between blue and brown wires 207 - 264 V. If supply
2
. Voltage between blue and brown wires 207 - 264V.
1
) and measure resistance between yellow wires on the inlet
5
) and measure resistance between the yellow wires on the pipe
6
) and measure resistance between Blue-Blue.
4

o
45 C
3.6~4.5 k
. Normal resistance across fuse < 1 If blown,
3

) connected.
2
) connected.
1
o o
60 C 105 C
2.2~2.7 k 0.6~0.8 k
Issue 1 - 6/04/09 ©Rinnai