Rheem 874W27NF - Page 21

21
TM061 Rheem 27 Water Star Service Instructions – Issued: 11/10
REV A Issued 08/13
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”
Diagnostic Points on Printed Circuit Board
Measurement Point
Normal Value
Point to Check
No.
Connection
Wire
Colour
1
A
BL1 – BR4
216~264 VAC
Main Power.
2
T
W1 – W2
50kΩ – 500kΩ
Over Heat Limiter.
3
S
BR1 – BK2
2 – 5 VDC (pulse)
>1310 pulses/minute
Water Flow Sensor pulse signal.
(Only when water is flowing)
R3 – BK2
11 – 17 VDC
Water Flow Sensor.
4
J
BL4 – W6
144 – 192 VDC
Fan Motor has proper voltage.
R3 – BL4
12 - 18 VDC
Fan Motor has proper voltage.
Y1 – BL4
4 – 10 VDC (Pulse)
>4800 pulses/minute
Fan Motor producing a regular pulse.
5
P
W6 – BK3
Refer to thermistor
resistance chart on following
page.
Cold water inlet thermistor.
6
P
Y5 – BK3
Heat exchanger thermistor.
7
P
R4 – BK3
Hot water outlet thermistor.
17
P
BL7 – BK3
Ambient air thermistor.
8
U
W1 – GND
0.3 – 100VAC
Flame rod not detecting flame.
14
1 – 100VAC
Flame rod detecting flame.
9
P
R1 – BK2
1.5 – 14 VDC
PGFR (Proportional Gas Flow
Regulating Valve)
40 – 80Ω
10
W
Y1 – BK8
75 – 100 VDC
GISV 0 (Gas Inlet Solenoid Valve 0)
(Primary fuel inlet to gas valve)
0.8 – 2.4kΩ
11
G
R1 – R4
90 - 110VAC
Igniter
12
W
W2 – BK8
75 – 100VDC
Solenoid valve (SV1)
(Fuel to ODS and front right burner)
0.8 – 2.4kΩ
13
W
R5 – BK8
75 – 100VDC
Solenoid valve (SV2)
(Fuel to back right burner)
0.8 – 2.4kΩ
18
W
BL6 – BK8
75 – 100VDC
Solenoid valve (SV3)
(Fuel to left side burner)
0.8 – 2.4kΩ
15
N
W2 – BK8
8 – 16VDC
Water volume control motor has
proper voltage.
R7 – BK8
8 – 16VDC
Water volume control motor has
proper voltage.
GR6 – BK8
Less than 1VDC (Limiter on)
4 – 6VDC (Limiter Off)
Water volume control motor position
switch is normal.
22
M
W2 – BK8
8 – 16VDC
Water bypass control motor has
proper voltage.
R7 – BK8
8 – 16VDC
Water bypass control motor has
proper voltage.
GR6 – BK8
Less than 1VDC (Limiter on)
4 – 6VDC (Limiter Off)
Water bypass control motor position
switch is normal.