Super Q Firebird 50/90 cutting out

Sokratees9

Hi,
We've a problem with our Super Q Firebird boiler.  It's probably 20 years old, so maybe we need a new, but if we can get it fixed, that would be great.  If it's been off for a while, when we start it, it fire up and runs as expected.  Radiators get hot and the hot water heats up.
It'll cut out after a certain amount of time.  The house is getting warm and all seems ok.  But then it won't fire up again properly.  It might start again about an hour or so later, but only run for a couple of minutes, then cut out, not enough time for the rads to get hot again, and the house doesn't heat up properly.
If I leave it to the next day, it'll fire up again like before, get things going as if it is actually working normally, but then the same issue.  We've plenty of oil, the water pump seems to be fine, so I can only guess it is maybe something weird going on with the thermostat in the boiler itself.  There is another thermostat in the hallway, but it looks older than the boiler, and doesn't seem to do anything...
We had someone out to service it, but he didn't seem to know much about this make or model (and it didn't seem to help at all).
Any ideas?
Thanks,
Stephen

DGOBS

A simple test, to start, run the heating, when the boiler reaches temp and is not cutting back in....
1. Turn down fully and the up fully up the room stat in the house, does the boiler now fire up? if Yes..room stats is faulty
2. If that doesn't work, then do the same, but this time, turn up the stat on the boiler, does the boiler fire back up? if Yes, faulty boiler stat

Super Q is a common boiler, and is known for boiler stat issues, but the bad news is, the stat is now obsolete!

Regarding your service guy, if unfamiliar with a super Q, get another service guy (oftec.org for a search) as would be expected he should know (it's his job after all!!)

Sokratees9

Thanks for the link, I'll see if I can find someone who knows a bit more about this Super Q set up.

After a bit more troubleshooting, I've gotten a little closer to working out where the problem lies. I removed the stat from the hot water tank, and once I do that, I can see the pump fires up again, and then a couple of minutes later the boiler fires up again (which makes sense, as it seems like the CH takes its heat from the HW tank).

When I put it back on again, soon after the boiler switches off again, and at some point later the pump goes off too. According to the guy who looked at it, the pump should be on all the time when the boiler is on, and that there may be a wiring fault with it.

I do have a feeling that the room stat hasn't worked in a long time. Previously I had tried turning it up and down from max to min, and it never seemed to do anything.

I've tried turning the stat on the boiler up and down, it doesn't seem to do much either...

John.G

Sokratees9 wrote: »

Thanks for the link, I'll see if I can find someone who knows a bit more about this Super Q set up.

After a bit more troubleshooting, I've gotten a little closer to working out where the problem lies. I removed the stat from the hot water tank, and once I do that, I can see the pump fires up again, and then a couple of minutes later the boiler fires up again (which makes sense, as it seems like the CH takes its heat from the HW tank).

When I put it back on again, soon after the boiler switches off again, and at some point later the pump goes off too. According to the guy who looked at it, the pump should be on all the time when the boiler is on, and that there may be a wiring fault with it.

I do have a feeling that the room stat hasn't worked in a long time. Previously I had tried turning it up and down from max to min, and it never seemed to do anything.

I've tried turning the stat on the boiler up and down, it doesn't seem to do much either...

"I do have a feeling that the room stat hasn't worked in a long time. Previously I had tried turning it up and down from max to min, and it never seemed to do anything"

While you are doing this you should hear a "click" each time, this at least might prove that the stat contacts are making and breaking, of course there could still be a wiring problem.

Sokratees9

Yes, there is a small click, always at the same point, around the 20-21 degree mark. It seems unchanged regardless of the temperature of the living space at that time.

But I could see why this could be a problem, as you would imagine that if the room thermostat isn't sending a signal to the pump, the pump might be off when it should be on.

jimf

reading through your post as tony dgobs says above sounds like a faulty stat

they are troublesome

even if not available you could always get somebody to wire in an external stat for you

the pump should not go off with the control temp stat on the boiler

John.G

Sokratees9 wrote: »

Yes, there is a small click, always at the same point, around the 20-21 degree mark. It seems unchanged regardless of the temperature of the living space at that time.

But I could see why this could be a problem, as you would imagine that if the room thermostat isn't sending a signal to the pump, the pump might be off when it should be on.

If its a faulty room stat then neither the boiler or the pump will run. If its a faulty boiler stat then the pump should still run even if the boiler is out on the high limit stat (or the boiler control stat). Normally the pump is only controlled by the room and/or the cylinder stat.

Edit: Only saw Jimf's post just now.

jimf

what position is the switch marked hw/hwch on the front of your boiler set to

or was it ever operational

Sokratees9

Can the room stat be replaced with anything modern? If so, that would be ideal

The switch on the front is usually set to HW/CH. I'm not sure how well it works though. Sometimes, when testing it previously, I've set it to HW, and only the tank gets hot (expected) and other times both radiators and hot water tank heated.

If we wanted only hot water (e.g. during the summer) we just used the immersion.

JamesM

It looks like you are indicating in your 2nd post (#3) that the thermostat on the hot water cylinder controls the circulating pump for the rads. This should not be.
You may need to get the circuit re-wired. Was that stat fitted recently, did you get a new cylinder recently ? If the boiler stat is not set too high - about midway, you could leave that stat off the cylinder, without doing any harm, until the wiring is sorted. See if this lets the rads heat. Also try to see if the room stat switches the pump on and off.
Jim.

Sokratees9

Room stat doesn't do anything. I would assume that would be the piece of equipment that would switch the pump on and off, so maybe that is where the fault lies. Nothing has changed with the system since we bought the house back in March. The heating probably wan't on much during spring/summer/early autumn, and maybe this was already an issue, and we're only seeing it now that we need the heat.

We plan to get an electrician in now to look at the wiring. Maybe we can replace the room stat to see if that can control the pump the way it should.

agusta

Its not a faulty room stat.Do you have 2 zones that you can turn on separate on the time clock
It sounds like the hot water and cylinder stat are controlling the pump and boiler [both,not separate]
motorised valve for rads may have been removed from it housing with the housing valve in the open position

JamesM

agusta wrote: »

Its not a faulty room stat.Do you have 2 zones that you can turn on separate on the time clock
It sounds like the hot water and cylinder stat are controlling the pump and boiler [both,not separate]
motorised valve for rads may have been removed from it housing with the housing valve in the open position

It looks like the cylinder stat is controlling the pump - not the boiler, because the boiler does not come on until the pump has been on for a while (see post #3: " I removed the stat from the hot water tank, and once I do that, I can see the pump fires up again, and then a couple of minutes later the boiler fires up again "). He does then say that the boiler switches off before the pump, but that will happen anyway, because the boiler can reach temp and switch off independent of the pump. The OP should remove the cylinder stat and see if the rads stay hot - also probably make sure that the boiler stat is set about half way.
Jim.

agusta

JamesM wrote: »

It looks like the cylinder stat is controlling the pump - not the boiler, because the boiler does not come on until the pump has been on for a while (see post #3: " I removed the stat from the hot water tank, and once I do that, I can see the pump fires up again, and then a couple of minutes later the boiler fires up again "). He does then say that the boiler switches off before the pump, but that will happen anyway, because the boiler can reach temp and switch off independent of the pump. The OP should remove the cylinder stat and see if the rads stay hot - also probably make sure that the boiler stat is set about half way.
Jim.

Hi Jim.
Post 3 is confusion really.The service technician didnt know much about the super q so that says enough.SoJim, im reading between the lines.my opinion is when the temp in cylinder drops,a live feed is send to boiler and pump.the pump starts,the burner starts a short time later,why,the boiler was already on and the stat on the boiler is satisfied.So temp has to drop for burner to start
I agree with you to remove the cylinder stat and run the system as one zone.it probably will work fine.
For me the question i would have,is there a two channel time clock.Why wont the rads zone come on separate.Are there motorised valves

John.G

agusta wrote: »

Hi Jim.
Post 3 is confusion really.The service technician didnt know much about the super q so that says enough.SoJim, im reading between the lines.my opinion is when the temp in cylinder drops,a live feed is send to boiler and pump.the pump starts,the burner starts a short time later,why,the boiler was already on and the stat on the boiler is satisfied.So temp has to drop for burner to start
I agree with you to remove the cylinder stat and run the system as one zone.it probably will work fine.
For me the question i would have,is there a two channel time clock.Why wont the rads zone come on separate.Are there motorised valves

The room stat has no effect, if the cylinder stat is just removed from the cylinder (or I presume if the cylinder stat is turned up to maximum) won't the pump/boiler (with the boiler cycling on/off on its own stat) run "forever"?. It shouldn't be too difficult for someone competent to sort this out properly.

agusta

John.G wrote: »

The room stat has no effect, if the cylinder stat is just removed from the cylinder (or I presume if the cylinder stat is turned up to maximum) won't the pump/boiler (with the boiler cycling on/off on its own stat) run "forever"?. It shouldn't be too difficult for someone competent to sort this out properly.

Yes John,Until the time clock is turned off.The same as a house that does not have zones.
I serviced a boiler/heating a few weeks back.house 15 years old.3200 sq ft.Boiler 20 metres from house.No zones or stats in house.Only stat is on the boiler.Madness [efficiency and comfort wise]
Yes turning up stat to the last would be the same as removing it.with boiler stat set low

JamesM

agusta wrote: »

Yes John,Until the time clock is turned off.The same as a house that does not have zones.
I serviced a boiler/heating a few weeks back.house 15 years old.3200 sq ft.Boiler 20 metres from house.No zones or stats in house.Only stat is on the boiler.Madness [efficiency and comfort wise]
Yes turning up stat to the last would be the same as removing it.with boiler stat set low

Back in the early 70s when oil was £30 for a fill (I remember £26 in 1974), many houses only had a boiler stat - the pump ran continuously while the timer was on. Sophisticated systems had a room stat in the hall or living room - in posh houses the stat controlled a mini-valve .
Jim.