Troubleshooting - Rinnai RHFE-551FA Service Manual

Troubleshooting

WARNING
There are a number of live tests that are required when fault finding this product. Extreme care should be used at
all times to avoid contact with energized components inside the furnace.
You MUST be a qualified service person before proceeding with these test instructions.
Before checking resistance readings, turn off power source to unit and then isolate each item to be checked from
the circuit by unplugging it.
When setting gas pressures on one of these units, please check the complete model number you are trouble-
shooting. Gas pressures and dip switches can vary among models. Always check the rating plate for complete
information and follow directions.
(TR) Transformer:
Read Voltage across:
WIRE COLOR
White - White
Red - Red
Black - Blue
Blue - Yellow
Grey - Grey
Purple - Purple
Black - Yellow
Brown - Purple
(SP) Sparker Board:
WIRE COLOR
Blue - Red
Set your voltage meter on the 400k scale, unplug the (5) pin connector on the sparker board. When reading
across the two lugs the blue and red wire connect to, you should read somewhere between l00k and 120k ohms
of resistance. When checking the spark sensing circuit, check across the orange wire (pin #35) and gray wire (pin
#32) on your 40 VDC scale. You should read between 4 - 5 VDC. During the spark this voltage will drop to
approximately 0 VDC. Once unit ignites the voltage will go back up to 4 - 5 VDC.
VOLTAGE
98 - 105 VAC
28 - 50 VAC
10 - 15 VAC
130 - 185 VAC
110 - 120 VAC
4.5 - 5.5 VAC
165 - 185 VAC
2.2 - 2.8 VAC
VOLTAGE
85 - 110 VAC
Rinnai Direct Vent Service Manual
RESISTANCE
READING NUMBERS
6 - 19 ohms
1 - 3 ohms
0.5 - 2.5 ohms
200 - 400 ohms
10 - 14 ohms
1 - 2 ohms
200 - 212 ohms
0.7 - 1.2 ohms
RESISTANCE
READING
see below
RHFE-431WTA
RHFE-556WTA
PIN
21 - 27
30 - 31
22 - 23
23 - 32
17 - 18
24 - 25
22 - 32
24 - 28
PIN
NUMBERS
33 - 36
21