Simple Problem, Maybe not

[Bert999]

I'm hoping someone here can offer some advice. I'll just give the basic information. The funace is a York upflow unit P4HUC16N09201. The heating cycle will not start. Here is the sequence of events:

1. When the thermostat calls for heat the ventor motor will start
2. The flames ignite in all 6 cells
3. After about 1 min the flames go out
4. The error code is 4 flashes

But, this is an intermitant problem. Sometimes the main air blower will start 15 sec after the flames ignite and all is well (no error code). After reaching the setpoint temperature the unit shuts off normally.

Also, the A/C system works fine. The main air blower always starts. The running capacitor is new also.

Thoughts? Thanks.

[Senior Tech]

Sorry Bert but we can not offer advice other than recommend that you call a reputable company to diagnose the problem on site.

[Bert999]

Sorry Bert but we can not offer advice other than recommend that you call a reputable company to diagnose the problem on site.

I understand but I have already called the contractor that put the system in. Since it is an intermittant problem he said to just keep track of the behavior for now. I'm just trying to get an idea of the problem for when I talk to him again.