HVAC Questions? Ask an HVAC Expert for Answers ASAP
All work to be done by licensed professional. WE KEEP GOING UNTIL YOU HAVE THE INFORMATION YOU NEED, I come and go. This is step ONE.
Failure to ignite can be caused by any of the following or a combination of these.
- Gas pressure a bit too high or too low
- Pilot/ main burner flame not impinging on the flame sensor rod directly enough.
- Lose wire connections in the control circuit
With a new boiler, and new parts, it is most likely that the gas pressure too high causing the burner flame to lift off of the burner head at times...when that happens the flame sensor will not be able to its job of leaking electrical current back through the flame to ground...and will shut the gas valve off and lock the system out.
OR... the gas pressure is set a bit too low, and the burner flame is not impinging reliably on the flame sensor rod..so it fails to detect the flame occasionally and shuts the gas valve down.
but since this was already apparently known and these pressures adjusted so frequently and you still have the problem... we must look at the electrical issues.
This could be a control card but thats not a common control card failure mode. stray electrical currents in the house neutral or ground wiring can cause such anomalies by interfering with the systems electronics.
Intermittent problems like this can be exceedingly hard to detect.
Sometimes all that can be done is to wait until it gets worse, and the problem more obvious or something fails entirely... then the fault is detectable.
Sometimes bending the flame detector rod a bit so it is more directly in the burner flame will solve the problem.
This unit attempts to refire 3 times before it gives the error code. However, if I simply toggle the power it will start right up. I've done this immediately after an A6 code. Any ideas why it would start then but not automatically?
The three attempts to fire before lock out is built into the controls.
when you toggle it on and off you are simply rebooting the controls before they have a chance to try the ignition three times and lock out
You might ask why it starts right up after you toggle it? Good question
I meant I toggled the power after the three attempts - then it started up.
toggling it resets the controls
why it then starts on the first try is a good question.
So you think it's a control issue?
it gets into the vagaries of the electronics
it is an electronics controls issue
but since the flame is part of of the electronics circuit itself, its also a flame issue
Some more info: it typically fails when calling for domestic HW. IS that a clue?
it could be that toggling it, allows the control card to shut down long enough to bleed electrons off of its micro circuits so they behave differently when the card is powered back up again
its something along those lines
if it fails when calling of DHW do you have to toggle it to get it to fire.
OK, thanks. I think you're right in that I'll have to wait until it gets worse before it gets better.
Same as I mentioned. It tries 3 times, gives an A6, then I toggle the power and it starts.
The time to press this issue is while its still in warranty, Now is the time to demand a fix, or something like a five year parts and labor extended warranty