16
RHT
Series
4.0
Troubleshooting Guide
Does the burner
stay on briefly and
then shut off?
Continued from page 14.
Check the gap on the
igniter. Is the gap between
3/16 in. and 1/4 in. ?
Check that gas pressure is within minimum and maximum inputs as
indicated on the heater’s rating plate. Is gas pressure ok?
Yes
Check that gas supply pressure meets
minimum and maximum requirements.
The following can cause the heater to shut down:
• Improper grounding.
• High winds.
• Taking combustion air from the attic.
• Dirty environment.
• Baffle not located properly.
• Fluctuating gas pressure.
No
Adjust gap.
Does the burner
stay on?
No
Does the heater stay on
until the call for heat ends?
Yes
Yes
Troubleshooting ends.
Is the heater properly
grounded? Is the
polarity correct?
Yes
No
No
Yes
Yes
No
Correct problem.
No
Flame Current Check: Single Spark & Sense
To measure flame current, disconnect input voltage, then insert a 0-50 μA DC meter and capacitor in series with the
spark electrode as shown below. Reconnect input voltage and initiate call for heat. After sparking is complete and
flame is established, meter should read 1.0 μA or higher while flame is established. If meter reads below “0” on the
scale, meter leads are reversed. Disconnect power and reconnect meter lead for proper polarity.
