Heating pump keeps running

[Kurt]

Hi . I'm a new member to the forum and would appreciate some expert advice . I have a open vented central heating system that appears to be working fine , plenty of heat and hot water . My question is that for as long as I can remember the pump runs continuously from the min the timer switches on until it shuts of late at night . Even when the water is hot enough and the room stat cuts out because the house is hot . The green light on the boiler goes out but the pump in my airing cupboard continues to run . Is this normal ? Is it causing any damage ?

Thanks in advance

kury

 

[spanner]

Is it noisy???
No its not a bad thing on an "open vent" system. Pump is meant to "overrun" when the system shuts down just to slowly dissipate the heat evenly. If you've good hot water and heating rate. You'll probably find its running intermittently where you're using the hot water from the hot tank. Pump and boiler will run to replenish and satisfy h/w in tank and again pump will continue to dissipate heat energy within the system.

 

[Kurt]

Hi the pump doesn't appear any noisier than any other pump . I sometimes have overrun on the the pump last thing at night when the timer goes off . The pump will run for a few more min . If I understand this correctly when the heat and water turn the motor valve off because it reaches temp the only place the water can go is out of the return which is a small 15mm pipe before the valve . This has a standard what looks like a rad lock shield valve fitted that is open half way . Is this correct or should it be fully open ? . I have never had any issues with the pump operation I just find it strange that it doesn't cut in/ out .
Thank for your help

 

[jonnyswamp]

A lot of variables as to why the pump runs continually, what age is the system, is it lagged, is the house insulated, is system designed correctly
If the house is an old solid wall type then the heating will only retain temp for a short time, so pump will pretty much always run (as long as heating is on) as boiler will only b e off for a short time as the building needs to constantly be re-heated and pump over run will always be active
Same with hot water, if you have an unlagged cylinder, it will be the same principal
However, if you have a newish energy efficient system, it could be that the pump is simply wired wrong

 

[Kurt]

Hi . The house is around 20 years old and is fully lagged . Had new boiler fitted about 6 months ago only because I wanted one more eff . The pump operation had always been the same with both boilers . Any advise on the return pipe/ valve . I have asked a couple of plumbers in the past and all have said different things so in a bit confused

 

[spanner]

Do you mean a secondary return pipe connection from the hot water pipe???

 

[Unregistered]

Hi sorry not sure of the technical term I was told by a plumber it was the return . It branches of the outlet from the pump just before it gets to the 2 way valve

 

[spanner]

Send in pictures would be obliged

 

[ShaunCorbs]

Think he means pumps on return and its normal for the pump to overrun for anything upto 10 mins

 

[jonnyswamp]

The valve is probably a manual bypass valve and should only be cracked open
What make of boiler and type of cylinder ie vented or pressurised
Post a photo of boiler, cyl and all controls in airing cupboard

 

[REDSAW]

sounds like your 2 port has jammed open then. cuases pump to run constantly.

 

[Kurt]

Hi
Photo attached of my airing cupboard . i have highlighted the valve im unsure about . i dont honestly think my pump question is overrun . even in summer ,no heat required and i have full tank of hot water the pump is running from the min the timer turns it on until the timer goes of . I have occasionally heard overrun at this point when the timer goes of at night . the pump will continue for a couple of min . As i have said its never caused a problem i just need to make sure its working as it should .
thanks

 

[spanner]

Then pump must be wired live with the timer I imagine instead of the boiler or the valve..!
Or valve jammed!

 

[ShaunCorbs]

The valve you have highlighted is a bypass (lock shield rad valve )

 

[Ric2013]

Where is the pipe running down from the gate valve going? It looks like it's running into the electrical enclosure on the pump. Or do my eyes deceive me?

 

[quality]

that's the cold water make up/fill

 

[spanner]

Where is the pipe running down from the gate valve going? It looks like it's running into the electrical enclosure on the pump. Or do my eyes deceive me?

Never seen a hot water cylinder with a 15mm hot water calorifier.
On the 3port central heating is 22mm and h/w 15mm going for the hwt?!!

 

[Davide13]

What's the make and model of the boiler? Have you got weather compensation fitted?

 

[Norcs]

The auxillary switch in the motorized valve must be energised from the timer and has probably failed. Not uncommon.
They are a crappy design.
Solid state timer relays are a much more elegant solution.

 

[Norcs]

Motorized valves must account for at least 20% of malfunctions in heating systems.

Installers continually use the crappy auxillary switch as a relay as its convenient.

 

[ShaunCorbs]

Motorized valves must account for at least 20% of malfunctions in heating systems.

Installers continually use the crappy auxillary switch as a relay as its convenient.

not true i remember when valves lasted alot longer because suppliers didnt use cheap parts so not down to us 100%

 

[Kurt]

Thanks for all the replies I'm going to book an electrician to check the wireing and motor valve . Could somebody please clarify my question about the return lock shield valve . How much should it be open , it's 3.5 turns from closed to fully open .

 

[ShaunCorbs]

normally about half a turn from closed but best to fit an auto one tbh

 

[AllyBongo]

Need the system wiring checked by someone in the know. Your system will probably bring the pump and boiler on at the same time. Room/Cylinder stat will, cut the pump/boiler out when satisfied. If you have no stats and your programmer is on, your pump will run constantly, boiler will shut off with the boiler stat. Let us know boiler make and if you have room/cylinder stats