Old Firebird 90 thermostat issue?

[unhandymann]

Hi all looking for some helpful advice


I'm an Aussie so go easy on me, I have a good mechanical engineering head but first time plumbing and dealing with kerosene burners/radiators as it's not something you'd see in Australia often.

So recently moved to Wexford Ireland and some radiators were cold and others luke warm

Bled the air out system with not much better results.

Serviced and cleaned the burner and heat exchanger which was looking like it was part of the Titanic and not been touched in many moons.

Replaced, new correct tip, correct pressure of fuel, tested the photo lens which was faulty and replaced, new line and fire valve also, but still same issue!

Also fitted a New grundfos Alpha 1 pump and valves as thought possibly a flow problem.

From here assumed it possibly was the control box or solenoid on the burner so ended up putting in a refurbished RGB 2.2 burner thinking rid of two possible problems and still the same result


So the issue now is the same before replacing the burner, it come on via the mains power switch and the controller won't control the burner but still powers the electric valves when switched on.

The controller inside will click and act like it's working and the red led comes on with the timer and it 'clicks' which I guess is the internal relay to control the burner but nothing happens?

My next point of call is the burner thermostat, ones turned on via the mains it does switch off once to temperature and then comes back on when temp drops so I'm thinking the second thermostat is working?

The only way to turn it off it via the mains switch so I guess it would be the first of the two thermostat controls or could it be the thermostat inside the house?

The issue currently to rule out the burner thermostat the only replacement unit available has completely different wiring (which I have)


* I've contacted 4 electricians in my area 2 don't want to know about it and 1 said almost 2 months wait!

 

[Avo Mk8]

Apologies, but I'm a bit confused!

The initial issue you were concerned about was some radiators cold and others lukewarm?
Back then, what was the situation with the temperature of the return flow at the boiler? If there was something like sludge in the system/ incorrect balancing/ pump problem/ airlock etc. the return temp would be high, and the boiler wouldn't be running much at all. I think oil boilers don't modulate, so if the return is already hot, they don't run full pelt for long until they reach set temp.

It seems you concluded that there was a problem with the boiler, and serviced it.
Having done boiler refurbishment and adjustment, replacing the pump etc. you say the issue is now "the same".
Then you say the controller won't control the burner. But then you refer to the thermostat and say it turns off when it reaches temperature, so implies something is working/ the boiler gets hot??
If you are suspicious of the thermostat, or the over temperature cutout, you don't need to change anything, you could surely just use a multimeter to check they are doing what they should?

Sorry but could you describe the symptom(s) that you need to fix a bit more clearly, not what you think might be wrong?

 

[unhandymann]

Apologies, but I'm a bit confused!

The initial issue you were concerned about was some radiators cold and others lukewarm?
Back then, what was the situation with the temperature of the return flow at the boiler? If there was something like sludge in the system/ incorrect balancing/ pump problem/ airlock etc. the return temp would be high, and the boiler wouldn't be running much at all. I think oil boilers don't modulate, so if the return is already hot, they don't run full pelt for long until they reach set temp.

It seems you concluded that there was a problem with the boiler, and serviced it.
Having done boiler refurbishment and adjustment, replacing the pump etc. you say the issue is now "the same".
Then you say the controller won't control the burner. But then you refer to the thermostat and say it turns off when it reaches temperature, so implies something is working/ the boiler gets hot??
If you are suspicious of the thermostat, or the over temperature cutout, you don't need to change anything, you could surely just use a multimeter to check they are doing what they should?

Sorry but could you describe the symptom(s) that you need to fix a bit more clearly, not what you think might be wrong?

Thanks for the reply

Well we moved in and I noticed a few weren't warming up as much, read up on it as I mean not ever seen anything like this in Australia. So bled and balanced the system to try get even heat on them.

After only minor improvements I checked the burner and heat exchange which looked like it had never been serviced so, cleaned all that out inside, new insulation and service to the burner.

One radiator the water is slightly blacker colour, which is my next job on the list to lock out each radiator and give them a blast through with the power washer. I think there may still be small amounts of air.

Yes it is old (Firebird 90) it was also doing quite short cycling which was an issue but the controller was working and switching on and off, so yes that was my conclusion as assumed it could be the control box or even solenoid so the best option was to change the burner as it was old and would eliminate 2 issues.

So as far as the controller, the electronic unit seems to be operating fine. It's on the timer works is clocks on and shows the red light and so forth.

The issue is what's happenings is the electric timer has power no issues, and all works by the looks. So timer clicks "on" and should turn on the burner and opens the valves which it can.

But if the mains switch is on it fires up regardless of the controller being in on or off mode, the timer clicks off the burner continues only way to control it is at the mains switch.

So currently we switch on at the mains and it fires up, house gets warm and to temp around 10_15 mins then switches itself off assuming by the secondary thermostat (again regardless of the internal timer) and once temp drops will come back on.

 

[Avo Mk8]

Do you have a multimeter, and know how to use it? Since the timer is apparently working, but not actually controlling the boiler, that ought to be fairly simple to fault find, by testing what is happening at the various connections.

If the timer was working OK before you changed the burner, but now with the new burner it's not, it sounds as if you might have put a wire (or plug?) back in the wrong place somewhere! Is that a possibility?

If you're not confident with diagnosing the electrics, could you get someone in to sort the timer issue?

I've found a bit more info- Is the boiler anything like the pic below?
The circuit diagram might not be the exact model.

PS The rocker switch for 24hr - timed is in the correct position for timer? Otherwise the boiler will run all the time!



So just a follow up, the only way the burner will get power, if the wiring diagram below is similar to yours, is if:

The mains switch is on
and
both the thermostatic cutout and the temperature control thermostat are 'on'
and either:
The 24hr switch is 'on' (which over-rides the timer)
Or
The timer is 'on'
Or
Terminal 1 of the six way terminal strip (at the top of the drawing) is connected somewhere providing a L supply
Or
If there is a wiring fault injecting power somehow on the burner circuit.

Or maybe the timer contacts have welded together so it's on all the time - can you make the burner light go on and off when the timer switches and are the timer tabs set up and operating the switch contacts as expected?

 

[unhandymann]

Ours has a digital timer inside, so not like the analogue in the picture.

I'm handy enough with a multimeter yes, use them with my work.

I did initially check for voltage at the valves because one was not operating properly, so it was getting really hot fast and then short cycle of 5 mins, it has now also been replaced and that side of it seems to work well, up to temp, reaches the thermostat limit, turns off then will re-start.

I've reset the timer system and gone though that but even with it powered and the heating system off on it the burner will come straight on when the mains switch for it on the fuse board is on.

If you turn the thermostat inside the burner/heat exchange unit it will fire up which to me shows the secondary thermostat is working.

It works as a dual thermostat so the second seems to do it's job but unsure if it's the first one possibly stuck 'open' or 'on' and causing this issue, but the replacement thermostat is completely different wiring as to why I'm not confident enough to wire it in.

No the problem is the same with the new burner, it only has 3 wires exactly the same, L,N,E so very straightforward.

I changed it thinking possibly the burner control was not working or the selonoid that opens the kerosene was faulty which would rule out those two possibilities.

Again it's my first time dealing with this type of thing so trying to work systematically through it.

I also changed the pump thinking it was a flow/pressure issue, but on removal no gunk or debris came out and the system was almost comply drained so had no reason to believe a blockage but that wouldn't explain it's auto power up.

 

[Avo Mk8]

I'm handy enough with a multimeter yes, use them with my work.

That's great. Do you have the circuit diagram for your boiler?

I've reset the timer system and gone though that but even with it powered and the heating system off on it the burner will come straight on when the mains switch for it on the fuse board is on.

Could you clarify this please. If you have the same rocker switches as in my photo, if the fuse board breaker is switched ON, does the boiler come on with the top left power switch OFF?
If the 24 hr switch is OFF, and the timer OFF, does the burner only come on with the top left boiler power switch on?

If you turn the thermostat inside the burner/heat exchange unit it will fire up which to me shows the secondary thermostat is working.

Agreed

It works as a dual thermostat so the second seems to do it's job but unsure if it's the first one possibly stuck 'open' or 'on' and causing this issue, but the replacement thermostat is completely different wiring as to why I'm not confident enough to wire it in.

I don't believe you should change the thermostats. I don't see how they can cause the issue. The present one is working, and the safety one must be closed (correctly) as they are both in series, and if one was duff the burner would not come on.

No the problem is the same with the new burner, it only has 3 wires exactly the same, L,N,E so very straightforward.

Leaving aside the various improvements you have made to the boiler, is the operation of the switches and timer, and what makes the burner run, exactly the same now as when you first encountered the boiler?
Or to put it another way - it works better now, but the switches and timer still do what they first did?
Is that the case?

Edit - final query - since you have an electronic timer, I suppose it's possible the switch output of the timer is permanently "on", no matter what the settings, because it's broken! So this could possibly all be due just to the timer! A job for the multimeter! Or you could test this theory by disconnecting the switch output of the timer, and checking that stops the burner coming on when you turn the boiler on!

 

[unhandymann]

That's great. Do you have the circuit diagram for your boiler?

Could you clarify this please. If you have the same rocker switches as in my photo, if the fuse board breaker is switched ON, does the boiler come on with the top left power switch OFF?
If the 24 hr switch is OFF, and the timer OFF, does the burner only come on with the top left boiler power switch on?

Agreed

I don't believe you should change the thermostats. I don't see how they can cause the issue. The present one is working, and the safety one must be closed (correctly) as they are both in series, and if one was duff the burner would not come on.

Leaving aside the various improvements you have made to the boiler, is the operation of the switches and timer, and what makes the burner run, exactly the same now as when you first encountered the boiler?
Or to put it another way - it works better now, but the switches and timer still do what they first did?
Is that the case?

Edit - final query - since you have an electronic timer, I suppose it's possible the switch output of the timer is permanently "on", no matter what the settings, because it's broken! So this could possibly all be due just to the timer! A job for the multimeter! Or you could test this theory by disconnecting the switch output of the timer, and checking that stops the burner coming on when you turn the boiler on!

 

[unhandymann]

I think this it the right timer diagram, the burner is an RGB riello 2.2 (replacement unit)




Original riello burner before replacing below




Not the same switches completely different, the system is a heat pack 90 Firebird but has a digital controller (grasslin towerchron qe2)




The current thermostat diagram




I think it's always been short cycling tbh but never really took much notice, the timer used to work and turn on the burner as it should so possible I disturbed something also?

It was working after the service fine then a few weeks went by and it started the continuous running problem.

I'll try removing the electric timer when it's running see if it cuts out ( I actually think I tried that but didn't do anything but will check again) it lifts up and comes off as it has an internal battery I think and the pins are all visible so maybe with the multimeter may be able check the congenuity of each circuit?


I'm actually away on holidays for a couple days and been going mad trying to get a sparky or heating technician in but when I tell them the issue they instantly are booked for months or don't do that type of work, and only being a small town very limited help as to why I'm resorting to try problem solve myself with the help of some knowledgeable people

Thanks the information so far appreciate the help

 

[Avo Mk8]

I'll have a look at that lot - many thanks.
A photo of the controls on your boiler might be a help!

I've had the wrong idea I think, the programmer in your case seems to be external to the boiler, on the wall?
And you have a "Y-plan" system, with a 3 position valve, a room stat and a cylinder stat as per the "Fully pumped system using 3-port mid position valve" schematic, and the boiler effectively getting its power from the orange wire of the 3 port valve - is that right?
Does the boiler have a switched live, or does it just have L,N&E and is powered from the programmer (via wiring centre?)

So the issue of "permanent on" of the boiler may lie in the wiring external to the boiler, or a faulty 3-port valve?

 

[unhandymann]

I'll have a look at that lot - many thanks.
A photo of the controls on your boiler might be a help!

I've had the wrong idea I think, the programmer in your case seems to be external to the boiler, on the wall?
And you have a "Y-plan" system, with a 3 position valve, a room stat and a cylinder stat as per the "Fully pumped system using 3-port mid position valve" schematic, and the boiler effectively getting its power from the orange wire of the 3 port valve - is that right?
Does the boiler have a switched live, or does it just have L,N&E and is powered from the programmer (via wiring centre?)

So the issue of "permanent on" of the boiler may lie in the wiring external to the boiler, or a faulty 3-port valve?

That's the electric timer, as we've only been in the house a year now still finding and sorting out little issues.

Apologies for my ignorance, I'm not clear on the 3 port reference?

Yes the burner is outside and the controller inside, also most the wires are brown from the controller so only way to check would be multimeter they go to a small junction box where they split off to the burner, valves, thermostat etc.

The burner only has the three wires (L,N,E) and an external small earth from the housing to the base of the steel cover.

I don't know if that diagram 100% the correct one for the controller, but below is the unit

Grasslin Towerchron QE1 Manuals - https://www.manualslib.com/products/Grasslin-Towerchron-Qe1-2974297.html


There is another old analogue room thermostat in the living room (attached a pic of a similar unit)

 

[Avo Mk8]

Apologies for my ignorance, I'm not clear on the 3 port reference?

A 3 port valve switches boiler flow between hot water cylinder and radiators, a common method called "Y plan", and is the scheme in the circuit diagram you posted with the thermostat etc. The valve looks like the pic below, and is probably near your hot water cylinder, but might be elsewhere. The boiler flow output goes into the bottom port, the rads come off one side and the cylinder the other.
Or the other option is you have two "2 port" motorised valves, one for hot water and one for the radiator circuit (called 'S Plan').
I'm keen to know if a 3 port is actually what you have, because it's the orange wire out of this valve that is providing the power for your boiler! And these things are known to get stuck etc!

Just to say that's it's clear now that the reason you boiler is running all the time is nothing to do with the boiler itself, it's that the power to it coming out of that junction box is not switching off when it should, so I think there's something up indoors that is causing your issue.

 

[unhandymann]

A 3 port valve switches boiler flow between hot water cylinder and radiators, a common method called "Y plan", and is the scheme in the circuit diagram you posted with the thermostat etc. The valve looks like the pic below, and is probably near your hot water cylinder, but might be elsewhere. The boiler flow output goes into the bottom port, the rads come off one side and the cylinder the other.
Or the other option is you have two "2 port" motorised valves, one for hot water and one for the radiator circuit (called 'S Plan').
I'm keen to know if a 3 port is actually what you have, because it's the orange wire out of this valve that is providing the power for your boiler! And these things are known to get stuck etc!

Just to say that's it's clear now that the reason you boiler is running all the time is nothing to do with the boiler itself, it's that the power to it coming out of that junction box is not switching off when it should, so I think there's something up indoors that is causing your issue.

View attachment 113539

Right thanks I understand, Yes I have to motorised valves ( Danfoss 087N6579 ) one for hot water and the other for the radiators so 2 port?

I changed actually one of these as it wasn't opening when I serviced it but when the inside control is switched to ' on' these both power up and turn as they should.and inlet and outlet pipes get hot.

 

[Avo Mk8]

Right thanks I understand, Yes I have to motorised valves ( Danfoss 087N6579 ) one for hot water and the other for the radiators so 2 port?

Thanks. The power for your boiler (and pump?) should be coming from the two orange wires of those Danfoss valves.
Circuit below (the 'junction box' you have may not have correspondingly numbered terminals, but the principle is the same!)
There are a number of tests you can do to see whether (being careful to switch off power while working) for example:

• If disconnecting both Danfoss valve orange wires stops the boiler working (which it should)
• If the voltage on the orange wires stays there when heating/hot water is satisfied/ timer is off (which it should not)

If one of those Danfoss valves is permanently on/open (or latched open) for some reason, your boiler will be permanently on.
Does this help at all do you think ?

 

[unhandymann]

Thanks. The power for your boiler (and pump?) should be coming from the two orange wires of those Danfoss valves.
Circuit below (the 'junction box' you have may not have correspondingly numbered terminals, but the principle is the same!)
There are a number of tests you can do to see whether (being careful to switch off power while working) for example:

• If disconnecting both Danfoss valve orange wires stops the boiler working (which it should)
• If the voltage on the orange wires stays there when heating/hot water is satisfied/ timer is off (which it should not)

If one of those Danfoss valves is permanently on/open (or latched open) for some reason, your boiler will be permanently on.
Does this help at all do you think ?
View attachment 113551

Thank you yes I understand the diagram and will try this tomorrow evening and report back the results thank you

 

[unhandymann]

So I haven't had the time or weather to get out the back and pull apart the wiring.

But I did turn on the timer inside and unpluged each valve individually and tried to shut them off via the controller but with with connected it continues to run.

Either one can be disconnected and the burner will continue to burn but with both disconnected it will not fire with the mains switch on, not sure if that helps narrow down anything at this point?

 

[Avo Mk8]

Did you conduct that experiment with both HW and CH calling for heat, or one of them, or neither?
It suggests to me that possibly at least one of those two valves is stuck, or one of the microswitches therein is welded closed.
I guess the next experiment is to find out which one is the problem. If you ensure neither HW or CH is on, and then repeat the disconnecting experiment, do you get the same result? You might hopefully find one valve disconnected turns the boiler off, but the other doesn't. It would be the one that doesn't that's the problem (or something in that circuit?)

 

[unhandymann]

Did you conduct that experiment with both HW and CH calling for heat, or one of them, or neither?
It suggests to me that possibly at least one of those two valves is stuck, or one of the microswitches therein is welded closed.
I guess the next experiment is to find out which one is the problem. If you ensure neither HW or CH is on, and then repeat the disconnecting experiment, do you get the same result? You might hopefully find one valve disconnected turns the boiler off, but the other doesn't. It would be the one that doesn't that's the problem (or something in that circuit?)

Both HW/CH on at the same time on the timer, unplugged each unit separately, then together and it will cut out.

One switch is brand new, so would assume it may be the other, they are turning the valve as they are ment to when powered on/off.

Yes I'll try switching on the controller tonight and do the same test on each valve, thank you hopefully getting closer to resolving this annoying issue.

 

[Avo Mk8]

Both HW/CH on at the same time on the timer, unplugged each unit separately, then together and it will cut out.

That seems to confirm to me that the boiler power is indeed coming via the valves, which it should.

One switch is brand new, so would assume it may be the other, they are turning the valve as they are ment to when powered on/off.

That's good the valves are doing something. The valve turning doesn't necessarily guarantee that the end travel microswitch gets operated. Or maybe the microswitch is just permanently on!

Yes I'll try switching on the controller tonight and do the same test on each valve, thank you hopefully getting closer to resolving this annoying issue.

To me the test is to turn off both CH and HW on the programmer, at which point you have said the boiler/burner still runs.
Then disconnect say the newer motorised valve.
If the boiler then cuts out, it's the new motorised valve that at fault, or it's not wired correctly!
If the boiler carries on running, it must be the older motorised valve that's faulty!

 

[unhandymann]

Hi Avomk8

Ok so test diagnosis still not sure.....


So mains switch on +

both valves disconnected
* doesn't fire (nothing works, timer has power and clicks between on/of red light comes on, with mains off the red light doesn't come on nor the switch/relay sound )

New valve disconnected & other original valve connected
* fires and runs valve operates (controller does nothing still)

New valve connected & other original valve connected
* fires and runs valve operates (controller does nothing still)

I removed the timer from the wall while both were plugged in and burner running and it shut down, so maybe a timer issue as both valves seem to be the same result?

 

[Avo Mk8]

OK clearly my suspicion of a valve being responsible is incorrect.
So that moves the problem back to the timer not doing it's job, or the wiring having an error.
I'm puzzled as to why there is a wire in terminal 2 of the timer. That is normally used when you have a 3-port mid position valve, eg "Y Plan"
Could you remind me what motorised valves you have, are they both 2 port, ie pipe in and pipe out. There's not a third pipe entering at the bottom of either?

It seems the timer itself is responsible for the 'always on' effect, but you say the indicator lights go on and off, and the relays click? Very odd.
Could you just confirm both the red indicator lights can be made to go on and off by adjusting the timer, and there is a 'click' associated with both?