Hopefully someone here can give me some ideas on what might be wrong
with my Day and Night heater (about 10 years old). Every few days it
fails to come completely on and it flashes a Ignition Proving Failure
warning message. But the other 98% of the time it works perfectly.

The details:
- It seems to do this in the early morning when it is changing from
the lower night setting to the higher day time setting.
- Removing power to the heater, waiting 5 minutes and turning it back
on seems to always fix the problem (based on three to 5 times)
- The thermostat was replaced and did not fix the problem
- The sequence is: low speed fan comes on, electric igniter glows,
gas jets are ignited, a few seconds later the gas is shut off, error
message flashes, fan continues to run for a while, then the sequence
repeats.

Thanks for any ideas that I can try for myself.

-Jim

wrote:
Hopefully someone here can give me some ideas on what might be wrong
with my Day and Night heater (about 10 years old). Every few days it
fails to come completely on and it flashes a Ignition Proving Failure
warning message. But the other 98% of the time it works perfectly.

The details:
- It seems to do this in the early morning when it is changing from
the lower night setting to the higher day time setting.
- Removing power to the heater, waiting 5 minutes and turning it back
on seems to always fix the problem (based on three to 5 times)
- The thermostat was replaced and did not fix the problem
- The sequence is: low speed fan comes on, electric igniter glows,
gas jets are ignited, a few seconds later the gas is shut off, error
message flashes, fan continues to run for a while, then the sequence
repeats.

Thanks for any ideas that I can try for myself.

-Jim


That must have a separate flame-sensing probe.

The probe may need cleaning/replacement.
If the probe doesn't report correct electrical
signal from the flame ("flame rectification"),
the control will signal failure to Prove Ignition.

Jim

wrote:
Hopefully someone here can give me some ideas on what might be wrong
with my Day and Night heater (about 10 years old). Every few days it
fails to come completely on and it flashes a Ignition Proving Failure
warning message. But the other 98% of the time it works perfectly.

The details:
- It seems to do this in the early morning when it is changing from
the lower night setting to the higher day time setting.
- Removing power to the heater, waiting 5 minutes and turning it back
on seems to always fix the problem (based on three to 5 times)
- The thermostat was replaced and did not fix the problem
- The sequence is: low speed fan comes on, electric igniter glows,
gas jets are ignited, a few seconds later the gas is shut off, error
message flashes, fan continues to run for a while, then the sequence
repeats.

Thanks for any ideas that I can try for myself.

-Jim

You might try also posting this question to alt.hvac.