Grundfos UPS 15-50 Power issues

[RobWD420]

hi,

I had a new UPS 15-50 hot water pump fitted by a plumber (I have a separate older pump for the heating) and on 4 occasions in the last month the boiler has overheated.

On the first two occasions I pressed the boiler override button to get everything working again.

On the last two occasions I noticed the new pump looked like it lost power (no lights). Overriding the boiler on its own didn't work on these occasions. the first time I had to cycle the mains as well and the pump came back on but this didn't work the second time and it came on about 48 hours later with out me doing anything.

If I wiggle the wire I can't get it to go on/off so I doubt it's a wiring problem.

I had a different plumber come and check the system (at a time it was working) and they reported everything was ok.

Any suggestions?

 

[DP]

Perhaps knowing what boiler you have might help?

 

[RobWD420]

It's a glowworm ultimate, about 15 years old I think.

 

[rules&rulers]

Maybe some photos so we can visualise your pump's,cylinder cupboard pipe arrangement,boiler pipe arrangement (not if pipes just leave boiler and route into ceiling) .

Good luck,

 

[RobWD420]

Ok, here you go.

Hot water pump is one at the back, the light was out when it wasn't working.

Boiler just goes into ceiling.

 

[Agile]

You have a thermal store! That can complicate matters.

You dont say under what conditions the boiler overheats?

Is it WHILE running? Or immediately it shuts off?

Normally a pump is wired to the boiler to provide an over run when it stops firing. With two pumps it may well need a relay to provide the over run.

If only the pump was changed it seems that there is another fault.

Why was the pump changed? Did YOU ask for the pump to be changed or did you ask the plumber to diagnose a problem?

Tony

 

[RobWD420]

So original issue was woke up one morning and had no hot water, there was a vibrating sound from what I believed to be the water pump down to the boiler. I thought it was the water pump because if I fiddled with it I could get the vibrating sound to stop for a bit.

I probably suggested it was the pump over the phone. Pump was replaced and plumber left, noticed no hot water and pressed boiler override to get it working.

All fine for a week where I find I have no hot water again and discover boiler override popped out, press it in to get everything working as normal.

Another week passes and same thing happens,this time I notice no light on the pump. To get power back to pump I reset the mains and have to press override again.

Decide to call a different plumber, he check everything and says it's Ok - "
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."

Another week later same issue, no light on pump and boiler overheated. Can't get power back to pump and boiler keeps firing up every few mins until after a few hours it overheats. Decided to turn boiler off. 48 hours later pump appears to have power, turn on boiler and all working again.

So boiler appears to overheat while it is running.

I suspect it will go wrong in about another week and not sure what to do now, unless I get a third plumber and more expense?

 

[Agile]

I would say that if the boiler is firing up for a few seconds then neither pump is working at some point in the operation.

To advance the diagnosis via the web you need to tell us which service is being provided when this happens.

Sounds like an intermittent connection in a programmer!

It needs diagnostic tests during this condition.

But if I was attending when it was working well then I would be checking contact resistances on each pump supply circuit. Relays with intermittent contacts usually have a high contact resistances.

Tony

 

[Agile]

I probably suggested it was the pump over the phone. Pump was replaced and plumber left, noticed no hot water and pressed boiler override to get it working.

It is always better to tell the plumber the symptoms and let him do the diagnosis.

If you suggest the pump is faulty then he will just replace the pump without diagnosing the actual fault leaving you with the problem.

He has carried out your instructions and cannot be blamed as he was not asked to actually diagnose any fault.

Tony

 

[DP]

Normally a pump is wired to the boiler to provide an over run when it stops firing. With two pumps it may well need a relay to provide the over run.

Tony, look at the Boilermate schematic before speculating
This way you will be helping the poster with correct information
FYI one pump circulates water between boiler and cylinder, other cylinder and radiators

Either I am going nuts and looking at the wrong stuff or you are you are posting for the sake of posting but lacking substance to assist the inquirer

 

[RobWD420]

The boilermate tank has a timer but we've always had this set to always on and just change the thermostat when we want the heating on.

We haven't really needed the heating for a couple of months so this has been mostly off and I've only put it on to test since the problem.

The only thing I've changed is that dial to set between winter and summer.

 

[DP]

Relays with intermittent contacts usually have a high contact resistances.

A relay with high contact resistance will be toasted beyond recognition
FYI a relay contact will more often not make contact due to constant make and break
You will not be able to check NO contact resistance while relay is in circuit when relay is operated
A multimeter will not give you true/ 'working' contact resistance

Again as I have asked often, show how you would achieve what you are preaching

Do not think you are being singled out but am questioning your professionalism like you do every time you post
Stick to what you know best and stop slagging posters or question others folk's ability and knowledge

 

[DP]

Rob, check if you have water in the header cistern

 

[RobWD420]

That's the small tank in the loft with a ballcock, if yes then it does have water.

 

[rules&rulers]

Oh it's a bloodyboilerunmatey.

your plumber should have done some basic checks to at least include,
boiler pump wired correctly to the boilermate,not wired to glowworm boiler.
wiring to boiler is as per boilermate instructions,
no programmer should be fitted,
pump valves fully open,
boiler pump pumping in correct direction,
sufficient water in system,
no restrictions in the primary circuit,
thermostat in glowworm boiler tested,
overheat stat in glowworm boiler tested,
sludge build up in boilermate and glowworm boiler,
scale in glowworm boiler,

The boiler pump is controlled by a delay timer in the boilermate, no neon light on the pump then it is either in a delay start or the store temperature has been reached.by switching the mains on/off the delay will be over ridden.
The delay timer could be intermittently defective,not always powering the boiler pump resulting in glowworm overheating .Although the boiler pump neon is illuminated this does not mean 230v is being supplied to the pump.

Maybe consider just nursing the boilermate & glowworm boiler along and save up for thermal store and boiler.

Others will have more suggestions,