Rheem 874W27NF Service Manual page 31

Fault Finding Tests 10 & 12-14
Test 13
1
3
S 2
1
2
T
1
1
U
3
2
V
1
Conduct test with flame present.
Using a multimeter set on the AC volts scale,
measure the voltage between W1 at terminal U
and earth.
Normal voltage should be 1 - 100VAC.
TM061 Rheem 27 Water Star Service Instructions – Issued: 11/10
REV A Issued 08/13
This document is stored and maintained electronically by
Tests 10 and 12
BK R BR Y G W SW1 SW2
1 2 3 4 5 6 7 8
K
7 BL
6 W
5
Y
N
4 R
O
9
BK
4 8 BK
2 BK
3 7 6
R
R
2 6 G 5
P 1 5 4
Y
4 BL 3
3 O 2
2 1
W
1 BR
Service. All printed copies not bearing this statement in RED are deemed "uncontrolled"
Test 10: Conduct test with water flowing.
Using a multimeter set on the DC volts scale,
measure the voltage between 1 Red and 2 Black at
terminal P whilst plugged into PCB.
Normal voltage is between DC1.5 and 14.0V.
Test 12: Isolate power before conducting test.
Using a multimeter set on the ohms scale,
measure the resistance between 1 Red and 2
Black at terminal P whilst unplugged from the PCB.
Normal resistance is between 40 ohms and 80
ohms.
Test 14
1
3
S 2
1
2
T
1
U 1
3
V 2
1
Unplug multi-pin connector from terminal T on
control PCB and using a multimeter set on the
kilo-ohms scale, measure the resistance of the
Over Heat Limiter assembly.
Normal resistance should be between 50 - 500
kilo-ohms.
31