grundfos pump not working

[IST]

I have a grundfos pump located on the primary pipes between the boiler and the thermal store cylinder. The pump is not working. The room stat is calling and the boiler is firing, but no circulation, just the flow from the boiler heating up.
I think the pump was working on dry pipes for a while when i lowered the water level to do a repair on the system for a while.
Would i have over heated the pump? or is there some sort of shut of switch i need to reset?

do i need a replacement pump, or is it something more easier to solve?

 

[Bernie2]

Hmm!

Could be burnt out.

Switch off electricity and check pumps armature and stator winding resistance value.

Ohms = Volts divided by amps. i.e 5 Ohms = 10 volts divided by 2 amps.

But if you don't have a multi meter, fill system and try to spin impeller, if free, turn on and see. If pump casing gets hot, yet water is cold then it may seem fairly obvious there is an internal pump problem.

 

[Mbear]

Turn the system on, check for voltage at pump, if voltage is present but no circulation, replace pumphead-simples

 

[IST]

Thanks.

when you say "replace pump head", do you mean, turn off the valves either side and replace the whole pump? or can i just replace a part of the pump?

 

[Billy Bob Bob]

be carefull ist,if this is a gledhill thermal store they dont use standard grundfos heads they are a special low voltage type,or they are on the 3 pump set up,you need a multi meter to confirm the pump has failed,gledhill charge about£98 for one

 

[Mbear]

Thanks.

when you say "replace pump head", do you mean, turn off the valves either side and replace the whole pump? or can i just replace a part of the pump?

no, there is 4 Allen key bolts on the pump. Unscrewing these and splitting head from body, do the same to the new pump you buy and just swap the heads. The body is just a body it has no moving parts and as long as the body isn't choked up then leaving It in place saves alot of hassle.

As gas man says beware if it's a 'boilermate' with it's unusual voltage setup, ie buy pump from manufacturer only.

Another thing to beware is, if you isolate the pump using the pump valves there is a very good chance that they will leak when you turn them off or if they don't then they can leak when you turn the valves back on. They are a repair engineers nightmare at times

 

[larrybob]

Could it be the capacitor burnt out? is that a starter capacitor?