Fuse blowing help

[tonybhoy]

Pump is the red thing in the pic mate.

Disconnect the cable going to and then turn your stat up to see if the fuse blows?

Personally I think it's a faulty motorised valve causing your problem.

 

[andersH]

Ok cheers! so I would just disconnect the cable which runs from this pump to the timer? what effect would this have on the heating or is this just to test?

 

[twgas]

I would say 3-port valve leaked internally, seized and blowing fuse.

 

[tonybhoy]

Ok cheers! so I would just disconnect the cable which runs from this pump to the timer? what effect would this have on the heating or is this just to test?

No just disconnect the three wires going into the pump and then turn up your stat to see if you are still getting fuses blowing when it 'clicks'.

Just ensure the three bare wires are clear of each other and any metal before you turn up the stat and that the power is off before disconnecting the cable from the pump.

Yes just a test.

 

[ollski]

Are you saying the hot water works ok but the heating doesn't?, what sort of system is it?. pics of the valve would help.

If you're on a fully pumped single pump system, which you are by the look of it, a faulty pump would blow on hw or ch demand. The demand from the clock is fine as its ok until you turn up the stat. If it blows immediately you switch the stat suspect room stat or valve and if it blows a few seconds later when the microswitch has energised suspect the valve.

 

[corgiman]

I agree with gremlin and dave its the earth being wired into no 3 which if i remember right (and I have had a few b now so it may let me down) is calling

BOOM

 

[simond]

If it worked when you first moved in, the earth wire on the thermostat is not significant. It should have had a brown (or red if old) marker, thats all. Need a picture of the wiring centre, the prog has not been used as one in this instance.

As some others suggest, it's likely to be the 3 port valve.

The OP is doing well because most of the respondents to the 'experienced heating engineer' advertisements we recently placed would be well behind him at this stage So still looking!

 

[stardanny]

I can see part of valve on left of pic. It a fully pumped "y" plan system, I believe. I think the motorised valve is faulty. OP say the hot water work meaning the pump work, I would say when room stat turn up, it turn on motorised valve which is faulty, thus blowing fuse.

Can you do a photo of a junction box just to check where that earth wire from stat go to?

Dan