Old Oil FireBird Thermostat Issue

DrBass

Hi Folks..

My Heatpac 90 26Kw started going into lockout recently. 

I checked on it when it was not firing, the boiler and burner was extremely warm. Hit the ‘Red’ button an reset, boiler took off again and worked for another day.

Same thing happened the next day again. Again - Hit the ‘Red’ button and reset, boiler took off again and worked for another day. Also this time hit the Reset button on the Thermostat and turned the boiler stat down to minimum 60*? (Was at about 70/75*)

Decided to also allow more cooling, so left open the access door lightly. (Boiler is outdoors stand alone) 

Rads have not changed in temperature at all (Should they?), still super hot like before. Indoor digital stats (Nest) read often 0.5* higher than the heat was called for, which normally they would not.

Bingo - No more issues, it's working. But it feels like I have just put a plaster on. 

I've checked the circulating pump, its old, but is working. 

Strangely I do hear the boiler shut off the odd time even when its still calling for heat and then firing back up again.

Boiler was serviced just over 2 months ago. Open system - small tank in attic (with water in it)

Sounds like a Boiler Thermostat issue right? or should I have other concerns?

John.G

If its the thermostat Hi Limit then you don't have to press the burner reset button (which would have been RED if you do/did have a burner problem) just the stat reset button after removing its little cover. Having the control stat set to 70/75C also should normally not cause a hi limit stat trip. Its also quite normal for the boiler to cycle on/off once up to temperature.

maestroamado

The best thing you can do is put the stat on the lower setting and bring it up gradually until you have the rads at the temp you want.... start pretty low and bring up gradually so it shuts down by the stat a few times.... you will have established if stat working ok when exercise is complete...

Wearb

If it was the boiler thermostat, it would most likely cause it to trip on high limit (the little pin beside the boiler thermostat dial)

Carefully check the pocket where the thermostat phials sit for insulating gunk.

Make sure there isn't air in the top of the boiler.

Can you post the reading from your recent service?

If it's tripping on the burner control (red button) it's unlikely to be a temperature problem, but flame drop out for some reason. BTW as it's only a couple of months, I'd aske to service person back to make sure that something wasn't overlooked.

Doing too many things at one time leaves it difficult to troubleshoot. (you turned stat down AND left door ajar) Boiler working better with door ajar is often indicative of escaping combustion gases.

John.G

Once its established which trip it actually is then easier to offer a diagnosis.

DrBass

Thanks fellas 

So when I first noticed it stopped working, the red boiler light was on ‘lockout’. The 2nd time also was on ‘lockout’. Once hit the rest button it fired back up.

(I only reset the boiler stat the little pin beside the boiler thermostat dial because I felt it maybe needed (Perhaps it never even popped out - does it need to? in order to be reset?, because system was so hot) I’m a novice really when it comes to this stuff.

''Its also quite normal for the boiler to cycle on/off once up to temperature.’’  

• Thanks good to know. 

''The best thing you can do is put the stat on the lower setting’’ 

• I have done this, its on the lowest setting, yet the Rads are still super hot as if I had not turned down the stat at all. But it seems to have fixed my issue. 

''Can you post the reading from your recent service?’’ 

• Pump Pressure - 9 Efficiency 95.2% CO 35ppm Excess Air 35.1% Nozzle Size 55 Angle 60 Pattern F?5 Co2 11.5% Flue gas temp 132*

''If it's tripping on the burner control (red button) it's unlikely to be a temperature problem’’ 

• Ok, thanks, thats interesting. 

Wearb

Pattern =ES

Flue temperature is only thing I see wrong with test results. Either not left running long enough before testing or under fired. How many rads (count doubles as 2) do you have?

Anyway I'm getting myself side tracked above as none of above is the cause of your problem.

Get service person back would be my advice.

DrBass

''How many rads (count doubles as 2) do you have?''

• 13 Upstairs about the same downstairs.

''Either not left running long enough before testing''

• more than likely this.

Wearb

With that many rads I'd guess underfired, unless your house has very good BER.

But if rads are super hot, then it's difficult to stand over paragraph above.

Anyway sort out your first problem and see where you stand with your boiler flue temperature after that.

jimf

your boiler run stat could be going out of calibration and going over the set temp hence the intermittent hi limit lock out

having to reset the burner lockout could be a few things but main cause would be capacitor or maybe tight spot on pump when hot

on off in quick succession could mean a combustion gas leak as already stated by wearb above

other than low temp the fga print out looks good

DrBass

''run stat could be going out of calibration''

• Interesting

''but main cause would be capacitor''

• Thats been mentioned to me by the tech thats coming out next week to have a look.

'' combustion gas leak''

I'll ask the tech to have a look into this also.

Thanks to all who have replied, appreciate the input. I will report back next week with the findings.

maestroamado

I am guessing that if you turned down the stat and still running too hot that the stat needs to be replaced.

This could also account for needing to reset as likely cut-out when system overheat....

John.G

But doesn't/will not cause the burner to lock out as the OP stated.

DrBass

Update: Juts now: So, I closed up the access door back onto the boiler last night (I had left it open as I thought boiler was getting very very hot). After working fine for the last 4 days with the access door open. Boiler went into 'Lockout' just now. WTF!

Wearb

As I said, it's leaking "fumes" somewhere. Get service guy back.

Now it could be something obscure, but above is usual cause for symptoms you describe.

maestroamado

get the guy back i expect the pressure in the burner is wrong so fuel nit burning properly... have you recently noticed more smoke from the flu....

DrBass

No, not smoky at all.

maestroamado

https://www.boards.ie/discussion/comment/118156529#Comment_118156529

tell us the outcome...

DrBass

https://www.boards.ie/discussion/comment/118173459#Comment_118173459

Combustion gas leak by the looks of it.

So its been taped & sealed (Needs a door gasket also) Job done - so far so good.

Thanks for all the advise fella's.