The heater is shutting down because the photocell does not see the correct flame color. Since you say "comes on for 5 seconds", I can only assume that there is a flame. You do not specify a lack of flame. I am also assuming that you have had the heater running this heater season and the problem just started.
YOU must find out if the problem is fuel related or electronics related.
Is fuel spraying into the combustion chamber?
Is the ignitor (glowbar) turning red?
Check the photocell for obstructions. It may be blind.
If you answer "yes" to questions 1 & 2, then your problem is most likely a fuel related problem. You must start by checking the pump pressure and find out if the air pump is operating to factory specs.
If the ignitor fails to glow, further troubleshooting of the electronics will be required.
Let us know what you find and report the results. Also, find the exact model of your heater if you have further questions.
Answers & Comments
The heater is shutting down because the photocell does not see the correct flame color.
Since you say "comes on for 5 seconds", I can only assume that there is a flame. You do not specify a lack of flame. I am also assuming that you have had the heater running this heater season and the problem just started.
YOU must find out if the problem is fuel related or electronics related.
- Is fuel spraying into the combustion chamber?
- Is the ignitor (glowbar) turning red?
- Check the photocell for obstructions. It may be blind.
If you answer "yes" to questions 1 & 2, then your problem is most likely a fuel related problem. You must start by checking the pump pressure and find out if the air pump is operating to factory specs.If the ignitor fails to glow, further troubleshooting of the electronics will be required.
Let us know what you find and report the results. Also, find the exact model of your heater if you have further questions.