My first post - heating pump advice please?

[andrewh8877]

Hello.
I have been reading this forum for a while but not posted anything yet. However, I can't find anything about a problem like this so thought I would ask. The plumbers we used to install it were awful so really not keen to go back to them!
.
We have a solid fuel stove with a back boiler which does the hot water and central heating. This is downstairs. There is one radiator and the hot water tank upstairs, there are three radiators downstairs.
The hot water and upstairs radiator are fine. However, the downstairs radiators which work from the pump are not getting hot at all. The pump is a one year old Grundfos UPS2.
There is a power supply to the pump, then a control unit of some sort with it's own switch. All fuses are fine and there is no loose wiring anywhere.
With the stove (and upstairs radiator) on the pipes on both sides of the pump remain stone cold. Is this odd, or would it only draw hot water through if the pump was running?
The little red light on the power supply for the pump (13amp) is on when the stove is off, but once the stove gets up to temperature it goes off. I have no idea what is going on here.
Everything worked fine last winter so I assume it's all wired up properly.
Any ideas what, and indeed how, I should check next?
Thanks,
Andy H

 

[Dan Robinson]

the pump remain stone cold. Is this odd, or would it only draw hot water through if the pump was running?

The pump need to be running.

13amp)once the stove gets up to temperature it goes off. I have no idea

Sounds lime a wiring fault /failure.

Any ideas what, and indeed how, I should check next?

Not from the information given. However, the ups2 was schit.

 

[ServiceNumpty]

I reckon they've wired the Hi/Lo stats the wrong way round.

 

[Echo the husky]

if the neon on the supply switch goes out when the pump should run, this would indicate no or a high resistance connection in the neutral somewhere. out of interest, what part of the UK are you in?

 

[PullerGas]

As Dan has stated, they're not great circulation pumps & Ive certainly replaced lots.
Also as Mike pointed out, there maybe Hi/Lo pipe thermostats on your system that could be causing problems, these are commonly fitted to eliminate low return temperatures to your stove.

 

[oilhead]

I reckon they've wired the Hi/Lo stats the wrong way round.

+1

 

[andrewh8877]

Thanks guys. Yes,there are two thermostats attached to the pipes,one near the fire/pump and one upstairs near the tank. If these were back to front though wouldn't it have never worked? It was fine last winter.
How would I check the neutral as Mr Huskey suggests? Is this a problem which could develop rather than be there since installation? It wasn't used for about 6 months over the summer if that makes any difference.
We are about 25m from Edinburgh, near Galashiels.

 

[Echo the husky]

If it worked fine before it's probably configured correctly. You need a 2 probe voltage tester to check, testing between L and N should be about 240V, between L and earth about 240V and between N and earth about 0V. Test on the outgoing side of the switch with the light, I would expect your readings to be substantially different than those listed, with the way you describe the light going out. check with the pump 'on' and off. Test again at the incoming side of the switch if the readings now match, the switch is faulty. If they still don't match, the fault is further back...

It may be something simple like a terminal screw on the insulation rather than the copper. Had a whole house with this exact fault in the summer, high resistance neutral connection on overhead line to house, low power loads worked, but higher power items switched on made all the lights go out.

 

[AGAS]

between N and earth about 0V

0 - 15v i expect you know that thou , splitting hairs i know

 

[Echo the husky]

Yea I didn't know exactly what to put, it could be all over the place if the earthing system is TT. Hopefully nearer 0V on TNCS and TNS!