Rinnai RHFE-551FA Service Manual page 25

Troubleshooting
RHFE-431FA Series
RHFE-556FA/FTRA Series
(H , H and H ) Safety Circuit:
1 2 3
Check for continuity across pins 44 and 46 at terminal H on the PC board. If you have no continuity, this means
one of these switch/thermal fuses is open. Replace defective component.
(OH - TH) Overheat Thermistor:
Check resistance reading across pins 12 and 13 at terminal A on the PC board. Proper readings should be 0.6 k
and 523 k. A reading below 0.6 k ohms indicates a short and a reading above 523k indicates an open circuit.
(MS) On/Off Control:
To check to ensure the on/off button is functioning, unplug terminal I. Place (1) lead of your meter on the red wire
for pin #66 and the other lead on the blue wire for pin#68. Now press the on/off button and you should be able to
read continuity through this switch each time the button is pressed.
(TB) Terminal Block:
This terminal is located on the right rear upper portion of the unit. On direct vents the jumper should be across
terminals 2 and 3. On units with vent extensions over four feet, this jumper should be across terminals 1 and 2.
IMPORTANT INFORMATION CONCERNING HARD LOCKOUTS:
Other items that can cause lockouts are: Improperly converted units, spider webs in burner and
air intake of vent system, improperly sized gas lines, low gas pressures or pressure drops due to other appliances
on the gas system, improper ground or no ground at receptacle, supply regulators freezing up or defective,
voltage drops or bad receptacle, winds in excess of 30 to 40 MPH causing turbulence inside the vent terminal, etc.
Rinnai Direct Vent Service Manual 25