carrier burner lights sometimes

[iceage]

Carrier 48dje064ca package unit with 3 burners. Gas pressures ok, pilot tubbing cleaned but, one burner (first stage) will only ignite when I hold hand over exhaust vent. Other burners run, same type of vendor motor on all 3 burners Anyone have an idea why by holding back exhaust it will allow burner to fire?

[socotech]

Is the wind deflector missing?

[iceage]

Yes. They were all missing ang found replacements

[socotech]

Maybe a wind problem. I have made some wind deflectors out of sheetmetal.

[socotech]

You have the post count. You should apply for pro membership. You will get a lot more answers.

[hands]

It could have a restricted orfice on the burner that doesn't light. You said this unit has a pilot tube, does the ignitor light the pilot at the burner that doesn't fire? The Carrier RTU's I usually work on have an ignitor with cross overs to light all the burners.

[mikeacman]

Looketh for spider webeths in your orfices

[qwerty hvac]

Looketh for spider webeths in your orfices

Check this. Very common on the carrier units.


Sent from my iPad using Tapatalk HD

[timebuilder]

Wow, that's an old Carrier to have a pilot tube. I haven't had a customer that is still running that era in over two years.

[mikeacman]

Also spider webs in your pilot tube

[iceage]

The pilot tube had been removed and cleaned. You can see pilot flame along bottom of tubing, but peeters out when it hits top tubing(u bend) and doesn't seem to hit sensor to open main gas, until vent is plugged.

[hands]

The pilot tube had been removed and cleaned. You can see pilot flame along bottom of tubing, but peeters out when it hits top tubing(u bend) and doesn't seem to hit sensor to open main gas, until vent is plugged.

Have you tried to increase the pilot gas pressure and did you check the orifice on the pilot tube?

[Push It]

check the heat excahnger for a crack in that tube.