Grundfos pump speed setting

[ruddyr1]

Hi, I fitted a new pump last year and put the setting to the highest speed number 3.

Ive noticed this year that when the heating chnges from central heating to heating the water and the diverter valve changes I get a thud as if the pressure or speed is such that the change in water direction cuases the thud. This is the only time it happens and evrything heats up and works fine.

Could it be the speed setting too fast?

What are your thoughts on the speed of pumps. I have 11 radiators in normal 2 floored house.

cheers

 

[misterdubya]

Honeywell Motorised Valve per chance? I live in a town house with 11 rads and my pump is on speed 1. The system here is clean though.

 

[Dan Robinson]

Could be - you should always have the speed as low as the system can take.

If the valve is thudding you cold have the pump on the wrong way. Or the valve might be on the way out.

Either way, try the speed on selection 2 for a while. If all is well move down to one.

 

[Agile]

The pump speed/setting should be that which creates the correct temperature differential across your boiler! You have not told us your model!

Generally setting "2" is adequate. But if setting "1" works fine and you live there then that will save energy.

Not recommended for tenanted properties though.

Tony

 

[gaswizzard]

Big problem with the honeywell mid position valves at the moment , when heating is satisfied along with hot water being called for the valve will bang shut causing a hammer noise within the pipework , I had to change a brand new one out because of this problem , what's happening here is the spring is too weak which in turn causes the motor to return too quickly , had to go for a different manufacture , hope honeywell sort this issue.

In this case it is nowt to do with circulator speed.

 

[Agile]

I dont follow that!

Surely if the spring is weak the valve will return more slowly ?

 

[gaswizzard]

Trust me , these valves have an issue , if the OP were to fit a valve from a different manufacturer his problem would be solved.

 

[Agile]

In that case I would say the springs are too strong and it returns too quickly!

 

[ruddyr1]

The boiler is ancient well, new when I bought the house 2oyears ago! Ideal elan with honeywell electrics and diverter valve. But I replaced that myself with in the past few years and everything seems to run ok.

Im gonna give the slower speed a run as suggested number 2 then see whats happens.

Thanks for advice.