Pump running continuously, getting very hot

[LEEDIYNOT]

Hi,

My central heating pump has started running continuously even when I turn off central heating and hot water at the controller. The boiler is also firing up occasionally.

The pump is starting to get noisier and very hot. Not sure what to try.

Central heating and hot water do still work ok so just a problem with the pump I think?

I've included some pictures:

Untitled

• LEEDIYNOT
• 20 May 2012
• 1

Untitled

• LEEDIYNOT
• 20 May 2012
• 1

Untitled

• LEEDIYNOT
• 20 May 2012
• 1

Thanks for your help,
Lee.

 

[45yearsagasman]

One of the end switches in those 2 port valves will have stuck, and my first thought is that it's the one with the white power head. If you are going to DIY then come back we'll guide you through a test procedure.

 

[swbjackson]

Probably a microswitch stuck on one of the zone valves. The boiler is not firing very often because there is no where for the water to go other than round the bypass circuit if there is one. If there isn't a bypass the pump is pumping against a dead end and this will dramatically shorten it's life.


Beaten to it

 

[LEEDIYNOT]

Thanks, I'm going to try diy if straight forward enough. The white box has a lever. Should I try moving it?

 

[45yearsagasman]

The only way to determine which valve head is at fault is to use a multimeter and to determine which orange wire from each valve is live when the system is off at the programmer. This involves electrical testing within the wiring centre/junction box. Once you have found the valve head which is faulty, the best bet is to simply change the offending head. Both of yours are removable and wired like for like. Live testing of the orange wires is the easiest way but you should not attempt this without the skill level required, for your own safety. A pro would diagnose and fix that within 30 mins, so the cost would not be that great.
The lever is a manual way to open the valve when filling a system and will not fix your fault. I emphasise that you must first determine which valve is the faulty one. I suggested the white one because they are prone to your type of fault.

 

[LEEDIYNOT]

Thanks for getting back to me. It sounded a bit above my skill set so i've rang an engineer who can come out in the morning. Will the pump last that long?

Is there any way i can cut power to the pump for now?

Thanks again

 

[45yearsagasman]

The only safe way is to switch off the fused spur and isolate the whole system. This will stop the pump, boiler etc.

 

[yerino]

What boiler do you have?

It could be the printed circuit board.

 

[LEEDIYNOT]

Thanks, I've switched off the fused spur for now until the engineer visits.

Cheers,
Lee.

 

[45yearsagasman]

It could be the printed circuit board.

Unlikely, when the boiler is also firing.