Boiler overheat cutoff after new pump fitted

[Rob247]

About 4 weeks ago I had no hot water and there was a vibrating noise which seemed to come from the hot water pump in the airing cupboard and go down to the boiler in the kitchen. I believed it was this as if I fiddle with the hot water pump I could sometimes get it to stop.


I had a plumber come and replace the hot water pump (based on my diagnosis now I think about it) and everything was fine for about a week when we had no hot water again. This time I discovered that the boiler overheat cutoff button had popped out and pressing it in got everything back to normal.


Another week later there is no hot water again. On this occasion the overheat cutoffbutton had popped out and I noticed there was no lights on the hot water pump. This time I had to press the overheat cutoff button and switch the mains on and off to get power to the pump.


At this point I got a different plumber (original plumber said might be boiler but he was not gas safe) to check the boiler who said "Investigated boiler and thermal store, tested stats and temperature differentials. Checked pumps on primary and heating circuits and also checked pump over runs. Found heating and hot water both working and no faults evident." Everything was working when he checked since I last reset the boiler.


Now another week later it's happened again, overheat cutoff popped out and no light on pump. This time I can't get the pump to power back on. If I press the overheat button the boiler it will fire up every few minutes for a few hours until the overheat pops out. During this time I do get hot water.


The boiler is a Glowworm Ultimate approx 15 years old.


I believe the new pump is a Grundfos UPS2 15-50/60, there is also a second older Grundfos pump but I believe this is for the heating.


Any advice, I've already spent £160 for the first plumber and pump and £75 on the second. I have the original plumber coming back Wednesday to look at the pump.


If the hot water pump was faulty or had no power would I still get hot water around the house before the override kicks In and it eventually cools down? From looking at the Grundfos manual online, it looks like the power light should be on all the time. Could the pump cause the boiler to overheat?

I did also have a smart meter fitted on my gas and electricity which happened after the original problem occurred but before the new pump was fitted. Could that be related?

Thanks


Rob

 

[Chuck]

Looks to me as though the cable to your new pump has been damaged just before it goes into the gland on the pump. So that's a likely cause of an intermittent connection. It shouldn't have been left in that condition. Be careful poking around as the damage may have created a shock hazard. It needs to be remade by a competent person, i.e. not whoever left it like that.

I don't like the way the pump isolation valves have been left skewed either. Also, they've left a rusty ripped piece of metal, which someone could slash themselves on in place. It should have been carefully removed or made safe.

So, that's three things that a competent plumber would not have done, or left if they'd seen them.

A SmartMeter is not going to cause the symptoms you describe.

 

[moonlight]

Just out of interest, is there water in the header tank?

 

[Rob247]

Thanks for the replies.

Yes there is water in what I think is the header tank.

I have come home today and the pump has power again! The boiler has been off for over 24 hours as we have been using the immersion plug.

Will the pump have some kind of cutoff? I don't believe it is the wiring as I've wiggled and pulled those about and never got it to come back on or now, off.

Any other suggestions? I'm not keen on getting the original plumber out again now as I imagine everything will be fine for another week and I don't want to get charged for nothing.

What else could be causing this kind of problem?

Thanks

 

[Allgoode]

Hi,
You said that you have a thermal store, is it a Gledhill by any chance?
If so and it is then you may have circuit boards controlling the pumps via pressure/flow switches &/or the boiler.
If you can post some pics of the thermal store in the airing cupboard then this may help.
I have a Gledhill in our house and bar the initial problems with the boards and the boiler not talking to each other and burning out it has worked fine since with regular maintenance.
Thanks,
Andy

 

[Rob247]

It's a boilermate2, pic attached.

 

[huddster]

I'd say blocked cold feed, unfortunately they have a U shaped bend as they drop into the store and are prone to blocking causing over heat issues and poor hot water. The heating will normally run fine as the pump is situated lower into the store and fully submerged In water whereas the pump for hot water is alot higher up.
If you can't unblock it is possible to re pipe from the drain off at the bottom of the store back upto the f&e tank.

 

[Reman]

I dont know whether you ever got to the bottom of this. But I had a similar problem following exactly the same pump replacement on a Glowworm Ultimate. I spoke with Grundfoss and they confirmed an incompatibility between this pup and the Ultimate Boiler!
They authorised a replacement and I changed to an Alpha? Problem solved. I feel really bad for not updating the thread at the time now, but I was so despondent!!
Boiler overheat tripping