Boiler starts then stops.

[GMAN6]

I have a Potterton Netaheat Electronic boiler a Grundfos pump and a small Honeywell aluminum box underneath the pump.

What has happened over the last few months is the radiators upstairs would be luke warm upstairs where as down stairs were hot, then gradually the boiler started to make some clanging noises which i thought was air so bled some radiators but no air came out. i checked the header tank and that was full, the pump seemed to be working fine but then it should its only a year old so released the screw in the middle to see if any air would come out but nothing, i then opened some bleed nipples in the loft on the ends of the pipes and a little air came out, the boiler fired up and things seemed to be working but then after a few hours there was a lot of banging and the boiler stopped so i got back in loft and bled nipples again but no air this time and the pipes from the boiler are hot but warm further down the run. i then emptied the whole system and done a refill and bled all the radiators now the boiler wont run for more than a few minuets. I have also noticed the Honeywell box under the pump has a small lever on it which when i use to press it felt like it was priming the pump but now that box does nothing the lever seems to be floppy. I know its a shot in the dark but does anyone have any idea what this could be please.

 

[Puddle]

well when lever 'floppy' means valve in open,so that seems ok,sounds like a circulation problem,could be blockage,however you say sometimes works,so would think air lock or faulty pump,first port of call,if when system on and you open nut in center of pump,should see spindle rotating

 

[GMAN6]

Hi thanks for reply, i just checked center screw of pump and there appears to be another screw underneath that one i cant see anything spinning is it worth taking pump apart is there any serviceable parts inside?

 

[Plumbstar Tom]

bang it with a spanner! might free it up

 

[GMAN6]

i put a small bit of washing up liquid in the hole of the pump and gave it a bang all seems to be spinning now, so touch wood all ok for tonight as its forecast a chilly one tonight. thanks again for all your help.

 

[REDSAW]

why is your f.e. tank full?

 

[GMAN6]

Whats f.e tank? the header tank that fills the system is full. the system worked fine all last night and so far this morning and its nice and quiet

 

[Plumbstar Tom]

the F E tank is the feed and expansion tank for the Central heating

This should be filled only part way to cover the feed pipe then an inch or so

 

[GMAN6]

Thats odd my tank is about 18" high and has about a foot of water in it, you wouldn't want the level any lower as the ball valve is quite high plus its a couple of inches below the overflow.

 

[GMAN6]

Pump seems to have stopped again and hitting it this time doesn't seem to have worked is the grundfos pump easy to take off and take apart?

 

[Billy Bob Bob]

yes it easy to take out but theres no serviceable parts inside if its a year old it will be in warranty but that will be void if corrosion is causing the pump to stick

 

[GMAN6]

I think it could be sludge that keeps jamming it up thought it might be worth taking it off and cleaning it.

 

[Puddle]

It will not be sludge stoping it,do not waste you time,replace pump,when you remove see if much build up of corrosion around inlet or outlet,pumps should last a lot longer than a year however what make is it.When you replace pump make sure isolation valves are open fully

imho

 

[Boyler]

just loosen the 4 alan keys and lift out, turning off isolation valves and draining boiler first. you can replace it with the same one or universal head.

 

[Puddle]

just loosen the 4 alan keys and lift out, turning off isolation valves and draining boiler first. you can replace it with the same one or universal head.

It’s a potterton neta heat not a combi or system boiler Boyler so if pump isolated not need to drain boiler, you maybe able to change head only but then pump guarantee gone, also if isolation valves have not closed correctly ,if not experienced ,once you loosen/remove head, you have a problem or the miss's does when she is frying egg and chips in the kitchen and dirty water starts falling on her new perm !!

imho

 

[Boyler]

sorry bout that puddle just caught end of the conversation