Hello everyone...pump heating problem

[katie666]

I just wanted to say Hello to everyone.
We've developed a problem with our Central heating pump running continuously since replacing the three-way valve. I'm just searching and working my way through past threads to see if I can get some ideas. This is a very informative board so I've added it to my bookmarks folder.

Katie

 

[Puddle]

Re: Hello everyone

Hi Katie
Welcome to the forums,hope you enjoy

if pump running all the time maybe system wiring requires double checking or could be a faulty pump over run ,what boiler is it ?

 

[katie666]

Re: Hello everyone

Hi Puddle. The boiler is a Glowworm Ultimate 60ff down in the garage. The pump is a Grundfos selectric in the airing cupboard and the three way valve is a Honeywell (previously a Danfoss HSV). The system was working fine till the engineer (not our usual guy) changed the 3-way valve in early June. All seemed well as we were just running the hot water over the summer. The pump doesn't run when we've just had water on, but since we were putting the CH on a few times last week, my hubby could hear the pump running during the night when the system is shut down and the three-way valve was warm even though all the pipes in the cylinder cupboard were cold. The pump runs on forever after the heating has been on, but will stop immediately if we switch the hot water on and then off again. We had the engineer back on Friday and he said that there is no power to the pump when the CH is switched off. However, even as he was saying this, the pump was vibrating and making a humming sound. He said the vibration must be coming from somewhere else in the house!! As soon as I switched the water on and put it off again, the pump was silent.

Katie

PS - should I post this in a different thread to the intro one??

 

[Gray0689]

How did he check the was no power to pump ??

 

[katie666]

Re: Hello everyone

He used a meter to check it when the heating was on and when it was off. I couldn't actually see what he was doing though.

Katie

 

[PlumbBobBob]

hi katie welcome to the forums

steveb

 

[tamz]

Your pump is powered from the boiler which has an over run but if it was tested and had no power the fault is with the mid position valve (noisy motor)
.
It is the motor inside this you are hearing.
Basically (bit technical ) this is what happens.
When you have heating and water on the valve is in the mid position. When the cylinder stat is satisfied the valve motor moves to the furthest position when it stalls and stays there but is still under power.
When the heating switches off the valve motor is still powered, the valve remains in the CH position but the system is off. This is why the valve feels warm.
When you switch the HW on and off this breaks the power to the motor and the valve returns to the HW side with no power to the motor.

Replace the motor or the valve

 

[katie666]

Thanks for the welcome and the help.
Tamz - Thanks for explaining the problem. The valve is under warranty so we'll get the plumber to replace it.

Katie