Central Heating pump overheating?

[lukeedw]

When my hot water/central heating system is on, the pump becomes really hot - as hot as the pipes around it. Is this normal? The system seems to function properly and I have bled the pump but it becomes too hot to touch again within about 5-10 minutes.

 

[muggles]

Yup, it's got the same temperature water running through it as the pipes either side, it's made of metal which is a heat conductor...it's going to be hot.

 

[JayJay1978]

I had this recently when I drained my heating, the pump was making a funny noise as well. It was very hot even after I bled it from the center screw.

It turned out the vent point above the pump was blocked (I wondered why no air/water came out!), once unblocked and bled it cooled down and sounded normal.

 

[lukeedw]

Two contrasting views! muggles, that is what I thought, the temperature of the pump is always the same as the pipes. But JayJay1978 seems to think it should be cooler. I don't have any noise issues with it and have bled both the pump centre screw and the vent above the pump.

Also, can anyone tell me what the pipe that bypasses the pump that has a stop tap on it is for? When should that tap be open and when should it be closed?

 

[kevplumb]

it ain't gonna be cooler that the water it's moving

stop tap or gate valve

 

[lukeedw]

sorry, gate valve (learning new things every day!)

 

[kevplumb]

probably your bypass valve (don't touch)

 

[lukeedw]

I take it that the bypass valve prevents the pump from trying to pump into a blocked system? In which case it should be always open?

 

[kevplumb]

the bypass (if thats what it is) is there to maintain a flow of water through the boiler when the system controls close down to prevent overheating