Rinnai RHFE-551FA Service Manual page 30

Troubleshooting
(FR) Flame Rod:
Flame rod - yellow wire. Low fire flame circuit should be somewhere around 1.2 to 1.8 micro amps,
depending on gas type being used. High fire flame circuit should be between 4 - 8 micro amps.
*NOTE: Improperly setup units can cause flame rods to carbon up. This can cause a hard lockout. If
carbon is found on the flame rod, remove the rod and clean it. Then you need to reconfirm
the manifold gas pressure, check air shutter setting, by-pass restrictor screw size and all
orifices for proper sizing. Also, the burner should be removed and cleaned.
Safety Circuit Test: TF
Unplug the black and red wire connector off of TR1 transformer, Then unplug the nine pin connector next to the
PC board. Now insert (1) lead of your meter into the grey wire connection at the nine pin connector and the other
lead to the black wire at the connection at transformer TR1. Set your meter to read continuity. Turn the control
knob to the on position. You should read continuity through the safety circuit at this time. If not, you need to
confirm which switch is defective and replace that component.
To check voltage through the safety circuit, place your leads in the black wire connection at transformer TR1 and
the grey wire connection at the nine pin connector at the PC board. With all components reconnected, turn the
control knob to the on position. You should read 0 volts AC across these two points. If you read anything above 1
VAC, there is a bad switch somewhere in this part of the circuit.
IMPORTANT INFORMATION CONCERNING HARD LOCKOUTS
Other items that can cause hard lockouts are: improper conversions, spider webs in burner and/or vent assembly,
improperly sized gas lines, low pressure or pressure drops due to other appliances on gas system, improper
ground or no ground at receptacle, supply regulator freezing up or defective, voltage drops or bad receptacles,
winds in excess of 40 MPH setting off pressure switch, etc.
30
, TF , TF , OHS, and M.S.
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Rinnai Direct Vent Service Manual
RHFE-551FA