Hayward H400 heater problems

[smd11873]

Hi All,

I have been troubleshooting an H400 series Hayward heater. Electric (non millivolt) H400 series. Newer version with Digital control panel. I find a lot of information regarding the older models but not the newer version. My H400 was purchased about 4-5 years ago. Its been used 3 seasons.

I may have 1 or possibly 2 problems. The other day I cleaned the burners out real good. They were clogged and had a lot of build up. I Checked the heat exchanger and it looks ok. I Placed the heater back together and it started perfectly. So quiet I didnt even think it started. It burned perfectly for 5 minutes then the blower would make noise like it was pulling or having trouble venting. Almost like It was clogged and bogging down. The heater then clicks as well. Sounds like its relighting the burner and the fan picks up again. Fan noise and Flame height start to go up and down, up and down, etc... Until you turn it off or place it in standby.

So to recap it will ignite normally after being turned off for a while but then after running a while and shutting it off it will only ignite after several tries with a large poof! It eventually ignites but its like a mini explosion. This must be the gas build up but why?

The other issue is the fan seems to bog down or not be able to vent after running for a few minutes. The up and down flame issue described above goes along with this. I tested the 2 hose lines that connect to the fan housing and when I apply pressure to the line one of the lines makes a healthy clicking noise as if the diaphram/sensor is working and the other does not. They both hook into seperate round shaped sensors or Diaphram devices. I believe they simply detect air flow. I believe this part could be bad and if so would it cause this issue?

If so does anyone have the part # for the Diaphram? Both are sensors to make sure the fan is running but I cant find them on a parts list. I tested both by applying very little pressure to the hose via my mouth. Where can I find the part number or description. I downloaded the manual but it doesnt list this particular part.

Thanks in advance!

Steve