Pump runs constantly, even when system is completely off!

[Denson]

I have a traditional emersion system in a 60's semi which has been changed at some point to use a modern boiler instead of behind the fireplace, but still uses a tank - i.e. not a combi. The pump runs constantly (even when the heating is completely off), it's very noisey and killing my leccy bill. Is this by design or some bad control wiring???

It also seems to have a thermostat that is magnetically attached to the tank. Is this safe? Surely if someone messes in the cupboard and catched the cable that runs to it, it could come off and over-heat with disasterous consequences? Can/should this all be corrected?

 

[Diyisfun]

If the pump has always run all the time, then design problem, if it never used to you have a fault.
The t/stat will not be held by magnet it usually springs.

 

[Denson]

Who knows? I bought the house a year ago. At least I know now it ain't supposed to be that way.

There is definately a water temp thermostat attached to the tank by a magnet. It's a firm hold, but it would be very easy if you caught the cable running to it for it to fall off. Bit worrying if I rented the place out!

 

[Denson]

Just to clarify, the thermometer has a magentic back to it, it's not some sort of bodge.

 

[gas4you]

This all depends on what type of system you have fitted. Gravity, fully pumped, 'Y' plan (3 port valve) 'S' plan (2 x 2 port valves)

Let us know this answer and we will be better placed to help.

 

[Denson]

I wouldn't know 100%, but there is a feeder tank in the loft.

 

[Softus]

I have a traditional emersion system in a 60's semi which has been changed at some point to use a modern boiler instead of behind the fireplace, but still uses a tank - i.e. not a combi.

Please specify the boiler make and model so that specific advice can be given.

The pump runs constantly (even when the heating is completely off), it's very noisey and killing my leccy bill. Is this by design or some bad control wiring?

Not enough information yet.

As well as the boiler make/model, please specify whether or not you have any motorised valves. Also the programmer make/model. Also whether you have a roomstat; ditto cylinder thermostat.

It also seems to have a thermostat that is magnetically attached to the tank.

If the tank is copper then nothing can be magnetically attached to it. Can you post a picture of this thermostat?

Is this safe? Surely if someone messes in the cupboard and catched the cable that runs to it, it could come off and over-heat with disasterous consequences? Can/should this all be corrected?

The boiler overheat thermostat would prevent a disaster, but it's never wise to store stuff all around the cylinder and its pipework and wiring.

 

[Denson]

I've arrived at the house to get further details. It does seem I was completely wrong about the magnet ...it's only been held on by being rested against a cable that holds the jacket to the tank. I've just secured it a bit better than it was. It still concerns me that it could be dangerous.

I've attached photos as requested.
The boiler is a Baxi solo 3.

 

[Denson]

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• Denson
• 22 Nov 2008
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• 22 Nov 2008
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• 22 Nov 2008
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• 22 Nov 2008
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[gas4you]

Without being there I would be suspicious of the boiler pcb. These have apparently got quite a poor record for faulting, although I have yet to find one at fault.

The pcb controls the pump.

If all the lights on the boiler are off and the heating/HW is off then I would look to change this.

You need someone in to check first though.

 

[gas_man_gaz]

id say the same as gas4you, changed about 5 to date where the pump overrun dosnt shut off

 

[Softus]

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• Denson
• 22 Nov 2008
• 1

There's nothing dangerous about it - it's intended by Honeywell that this thermostat be retained by curtain wire, but not how you've done it.

There's a channel on the 'stat casing for the wire to sit, and you need to cut it to length so that there's tension in it.