Pump & Motorised Valve

[harrypearce1]

Good morning, I am new to this forum and was after some advice if at all possible, hopefully one of you may be able to point me in the right direction.

The boiler (Suprima 60L) is located in the kitchen with cold water tank and hot water cylinder in the loft. There are two motorised valves in the loft which as I believe one controls the hot water and the other controls the heating. The pump is also in the loft.

When the hot water is running off the boiler (heating completely switched off on the wall programmer) the pump overide doesnt cut the pump off once the hot water is up to temperature and isnt calling to be heated. The pump continuesly runs and gets really hot.

If I am running the heating and hot water together the pump shuts off as it should when the rads & water are up to temperature. If I only run the hot water and then turn the boiler control right down to off the pump will switch off. Could it be that there is a problem with the motorised valve? very confused!!!

I had a new PCB and fan about 3 months ago.

Any advice would be very much appreciated.

Thank you.

 

[doitmyself]

The pump should be connected directly to the boiler, where it is controlled by the overrun thermostat. This is supposed to keep the boiler running for a few minutes after it goes off.

Might be worth checking if it is wired correctly, as a faulty overrun stat would show up if either heating or hot water were involved.

 

[kris]

Hi there harrypearce1 and welcome along,,,, by the sounds of it everything is working fine, the reason the pump keeps pumping on hot water is because the hot water zone valve is governed by a tank stat attatched to the hot water tank in attic and although the temperature inside the pipe work going to the tank is up to temperature the water in the cylinder is not , therefore it takes a lot longer for the hw to come totally up to temp, hope that makes sense, and your boiler doesn't have an overrun but newer models do,

 

[doitmyself]

your boiler doesn't have an overrun but newer models do,

Have you checked the wiring diagram of the Suprima 60L recently? I have and it definitely shows the pump connected to the boiler and says that this is necessary to allow pump overrun.

 

[SavageW]

Strange one if the pump overrun behaves it self when both demands on, would get a qualified to check over where the pumps wired to - as said before should be straight from boiler, could be coincidence that you've noticed it when the HW demands on, maybe sticking micro switch on HW valve constantly feeding boiler which would run the pump but would of thought you would have noticed the boiler staying on