My Projects

Published 18 Jul 2019

Rinnai RHFE-551F


Overview

Rinnai 551F Gas Heater
Rinnai 551F Gas Heater

System operation

On power on the red LED should light, then within 2 seconds the combustion air compressor fan should start up. After running 15 seconds there should be the sound of the gas being turned on and the gas should be ignited and visible in the viewing window. After heating for a while the convection fans should switch on (about 40 seconds after ignition).

Hardware description

Faults

If the power light comes on then switches off after 10 to 20 seconds with nothing else happening, then the combustion compressor fan isn't starting. The fan may be stuck, or there may be bad connections to the relays (bad solder joints or connectors), or the relays may be faulty. The fan operates off 100V AC and is powered through 3 wires, white, red, blue. White is neutral, blue is powered for low speed operation, red for high speed operation. Within 2 seconds after power up there should be 100v on the blue wire and the fan should start. If there is power there and no fan movement then either the fan is stalled, the starter capacitor is faulty, or the motor is burnt out. The starter capactor (2.5µF 220V) can be temporarily swapped with the blower motor capacitor (3.5µF 220V) to see whether that is the problem. I would expect to be able to smell burnt out windings. To physically turn the motor is difficult without either unmounting it, or dissasembling the motor. Beware of the high voltage electrode wire connected to the sparker which is in the way and could be damaged in trying to remove the motor.

References and Additional Resources

If any referenced page no longer exists, try looking for its URL on http://archive.org.