Honeywell R4795 primary control

Centurion

Hi all, a problem has occurred on my boiler burner control, it's a gas burner with pilot ignition. This failure mode was not described on the honeywell manual and I thought people on the main wall can help me out on the problem. On start, during purge period I observe relay 2k clicking in and out several times and the system goes to flame failure mode in purge stage. by which I have to reset the safety switch(is this called a lockout?). My understanding from the manual it seems that relay 2k only pulls in after purge is complete. What could be the possible causes for this problem. This problem occurs perhaps 50% of the time, sometimes the boiler will start just fine. plug in amplifier is purple.



Thanks

Steamhead

Must be a larger burner

make sure you have a good flame signal. A loose lock nut on the UV flame detector can interfere with the signal and cause lockouts. 

Centurion

follow up

During purge the flame signal is still being captured? What kind of signal will cause the lockout I described earlier?



Thanks for your help

Steamhead

I'm pretty sure

it looks for a flame signal during the purge, locking out if it sees one. I believe 2K is also called the "flame" relay, since in the diagram it appears to be fed thru the purge timer and flame amp, with its contacts operating the main gas valve and cutting off the ignition.



Make sure everything's tight, since a bad connection can cause strange things, then check to see if you're getting a flame signal during purge (shouldn't be) and during TFI (should be).

Centurion

follow up

I have had another lockout after changing the flame amplifier, I will re-inspect the wiring connections. But I am now completely clueless, could there be something wrong with the flame detector? How do I measure flame current, must I buy a Test meter with the meter connector plug?