Our Potterton Prima boiler didn't come on this morning although the programmer red lights were on. We had to go into the garage and press the restart button. Why does this happen? It's less than a fortnight since it was serviced, along with our other boiler at £75 each plus VAT which we thought rather expensive; no concession for the second.
ignition failure
- Thread starter patagonia
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I'll do that if I can find the expansion tank. However, the heating was working OK till we went to bed last night and has been working OK since we pressed the restart button. I can't see how it can have overheated if it didn't come on till then and I could tell by the room temp. when I woke up that it hadn't come on at the usual time.
The expansion tank was OK so the problem must presumably be with the pump. Most mornings the heating comes on OK but there have been 3 mornings when it has not done so and we have had to go into the garage and press the restart button, after which we have heating for the rest of the day. If it is the pump, what exactly is happening? Does it mean a replacement or is there any maintenance that can be carried out and should the pump be checked when the boiler is serviced? I can't understand why it should happen some times but not others. Could it be anything to do with the frost stat coming on during a particularly cold night? Any suggestions gratefully received.
It could be a number of things which will all need checking. Could be the pump overun part of the thermostat is not activating after switch off so it could be overheating after your evening period which would explain why its failed before the morning period. It could also be a poorly performing pump or a slight blockage somewhere. How much of this you could check yourself depends on the extent of your skills/knowledge of heating systems.
150+vat for 2 boiler services is a bit on the high side imo. Would have done it for about half!
150+vat for 2 boiler services is a bit on the high side imo. Would have done it for about half!
Thanks Mickyg. We had the engineer back and he said we need a new pump but I'm not totally convinced. I think you may be right about there being a blockage, ie a bit of debris in the system which moves around and gets stuck, which may explain why some of the radstats sometimes don't work. I noticed that one rad had gone cold a few days ago although it was on high and the others were hot. After I had jiggled the knob from max to min and back again a few times it came on and has been OK since - till the next time. It's one damn thing after another. Anyway, having had an estimate for £217 plus VAT for installing a new pump, I think we'll keep an eye on it for a while; if it's only an occasional trip to the garage, it's perhaps not worth the expense. I'll also switch off the system during the day and make sure the pump carries on running.
What I was really asking is whether pumps can be serviced or is it a case of replacing them when they break down.
We've moved from Herts to Bucks; otherwise I'd be asking for your number!
What I was really asking is whether pumps can be serviced or is it a case of replacing them when they break down.
We've moved from Herts to Bucks; otherwise I'd be asking for your number!
.... "What I was really asking is whether pumps can be serviced or is it a case of replacing them when they break down."
Other than bleeding there is no servicing possible with a pump.
For the enthusiast engineer who would remove and fit a pump him/herself it may well be a practical proposition to dismantle and rebuild pumps but if you are paying someone to do that for you it does not make economic sense.
Other than bleeding there is no servicing possible with a pump.
For the enthusiast engineer who would remove and fit a pump him/herself it may well be a practical proposition to dismantle and rebuild pumps but if you are paying someone to do that for you it does not make economic sense.
Check the pump speed setting is at least on "2" or higher.
It maty be sluggish to start up in the morning.
I could chemically clean a pump. But you could add Sentinel X400 for four weeks and then drain and add X100. That would clean the system and might help the pump IF that was the problem.
However, I am more inclined towards thinking its the boiler overheating AFTER the demand and when it switches off.
That could be as a result of scaling/sludge in the heat exchanger. But that would only occur if the boiler had no pump over run or it was not working. I did not think your boiler had it.
Tony
It maty be sluggish to start up in the morning.
I could chemically clean a pump. But you could add Sentinel X400 for four weeks and then drain and add X100. That would clean the system and might help the pump IF that was the problem.
However, I am more inclined towards thinking its the boiler overheating AFTER the demand and when it switches off.
That could be as a result of scaling/sludge in the heat exchanger. But that would only occur if the boiler had no pump over run or it was not working. I did not think your boiler had it.
Tony
Sorry to be dim, Tony, but you didn't think our boiler had what? It's a Potterton Prima. Incidentally, the engineer said that there was quite a bit of inhibitor sitting in the expansion tank, obviously added by a previous engineer who didn't ensure it got into the system. Could this cause any problems?
"It" being a pump over run.
The inhibitor works its way into the system as thesystem water expands and contracts. ( Unless its a long pipe run to the system connection ).
You can ensure it flows in by bleeding out about 4 litres from a distant rad.
Tony
The installation instructions refer to a pump over-run thermostat and an overheat thermostat. How do I check whether both of these are working. As it was very mild here this a.m. and it was a bit too warm for doing my housework I turned the programmer off and when I turned it back on this afternoon, it didn't come on again and we had to press the reset button. All seems to be working now. I am not all that knowledgeable about heating though have picked up a few things over the years and it seems to me that it is more likely that the over-run stat isn't working so the overheat thermostat cuts out the boiler. What do you think? And is it an expensive job to replace the thermostat? We have been running the boiler on 5 (i.e. next to max.) as I think the rads are undersized in some areas. I note the pump is set on max as well.
Those boilers have a too wide range of control on their user knobs.
Running them at max is too close to the operating temperature of the o/h stat.
I advise users not to exceed about 3 1/2 for normal use.
To see if pump over run is working turn off boiler and see if pump stops immediately.
But is the pump wired onto the boiler so the over run can work?
On that age of boilers the over run stat was a change over stat but as its inside the combustion chamber my advice must be that changing should be by a gas engineer.
Tony
Running them at max is too close to the operating temperature of the o/h stat.
I advise users not to exceed about 3 1/2 for normal use.
To see if pump over run is working turn off boiler and see if pump stops immediately.
But is the pump wired onto the boiler so the over run can work?
On that age of boilers the over run stat was a change over stat but as its inside the combustion chamber my advice must be that changing should be by a gas engineer.
Tony
I can't climb up a ladder but my husband did and says the pump stopped vibrating as soon as I turned the programmer off and the boiler stopped firing. So what needs renewing?
As regards the wiring, there is a wire coming from the pump down the wall to a switch and from the switch 3 wires go into the boiler. We haven't taken the case off so not sure what happens inside. We've turned the boiler down to 4 and a half (6 is max and we had it on 5 which we need when the weather is really cold). Can't see why they have the higher numbers if it's not advisable to use them. We were given to understand years ago that you get maximum efficiency if you run the boiler at 70 degrees.
You get the maximum efficiency if you run it at the lowest temperature that provides enough heating.
Just because you car can drive at 100 mph does not mean that you should!
You need to see how the pump is wired. It sounds to me as if its not connected to the boiler to take advantage of the pump over-run if fitted. You need to check the connections at the boiler to identify where the pump could be connected and see if anything is connected there.
Tony
Just because you car can drive at 100 mph does not mean that you should!
You need to see how the pump is wired. It sounds to me as if its not connected to the boiler to take advantage of the pump over-run if fitted. You need to check the connections at the boiler to identify where the pump could be connected and see if anything is connected there.
Tony
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