rdb2.2 firebird boiler intermittent lockout

bcolemax

Hi, wondering if anyone can help with issue on my sisters firebird oil boiler exact model in title. Its been having intermittent lock out problem for some time. She's had it serviced which has not helped. Not sure exactly what was done during service but was done by local professional.

Issue is it can run for hours with no issue then goes into lockout and have to press the reset button. Sometimes it fires up straight away after one reset but sometimes takes a few resets.

I think when issue is present it sounds different when you press reset like as if motor is not spinning as no real blow sound out of it. I can tell if it's going to fire or not based on sound when I press the reset.

I have similar boiler where most parts are compatible. So far I have swapped out solenoid and control box but issue remains. The photocell looks clean but I have not swapped yet, maybe next thing to try.

The capacitor was changed few months ago as was reading very low uf and not firing at all. As far as i remember it had similar intermittent problem few years ago and plumber changed capacitor that time and issue went away. Current capacitor is reading as it should though 4.5uf on DVM.

If photocell does not help I was thinking of swapping motor with mine but don't really want to go pulling the motor off of mine.

I would be really grateful if anyone who may have seen similar could advise. Are there any voltage checks I can do when issue is present that might point to issue?

I know if i call plumber back boiler will most likely work fine while he's there.

Thanks in advance

Brian

jimf

could be a tight spot on the fuel pump

bcolemax

Thanks Jim, are there any checks I can do on the pump or is it a case of swap them and see?

jimf

if you split motor and pump you may find a tight spot on the pump as you spin the shaft

Wearb

Motor bearings can also cause this.

While I've not come across it, I've read of people having changed seemingly good capacitors to find the replacement worked. I don't know if that just somebody's coincidence because as I said, I've never found that to be the case.

bcolemax

Thanks guys i will check out pump on Thursday (next opportunity). Don't want to touch my own pump until I get my hands on a pressure gauge to check/setup the pressure. Any recommendations on relatively cheap pressure gauge that will fit ?

jimf

i know what you trying to do but you could be potentially leaving an unsafe boiler at your sisters

if the boiler is outdoors it negates it a little

whatever you do dont touch the pressure adjusting screw in your own boiler

1/8 bsp back entry pressure gauge but this only tells you the pump pressure doesnt give you the overall picture of how boiler is running

you will need a flugas analyser for this and at nearly 1k would be an expensive purchase

bcolemax

Thanks Jim it is out doors but i won't touch the pressure adjuster on either of them. I will just check pump for free rotation for now.

Looking at manual the two burners have different pressure settings on the pump anyway so will definitely leave mine alone.

bcolemax

Ran fine from Sunday but went into lockout again today so took pump off and sure enough there is a definite spot where it sticks when turned by hand. Compared to my own which has no resistance to turn.

Can this be repaired by opening and cleaning or am I looking at new pump?

Also assume if I get new pump need service guy to change it who has gas analyzer for setup ?

Or if pressure set same as old one and according to manual will that be good enough for outside boiler?

jimf

golden rule when you find faulty open pump and check for any water contamination

this usually presents as gunk inside in filter but in your case i dont think this will be the case as i would have seized by now

i would get somebody to supply and fit new pump if needed and also service and set up boiler properly

bcolemax

Grand thanks it's 14 years old so might be as well to just get new burner installed as can get it vat free through work and keep old one for spares