Central heating pump

[cardiffrob]

Well, mine runs continuously, day and night. I think it may have been doing so for the last 4 years since we bought the house. The noise from it, a gentle hum, has been part of normal life for so long that I only noticed the pump running at night when I accidentally knocked the electrics off in the airing cupboard. Is this a normal state of affairs? Seems unlikely, but I thought I'd ask. I looked around the pile of copper spaghetti but become lost. It is a Grundfoss crimson coloured pump with a 3-speed selector on the side.

Any suggestions or insights would be gratefully received.

Ta.

 

[mike os]

Should only run with the boiler and maybe a few minutes over

 

[the snooper]

Doesn't your wall mounted thermostatic switch it off ?

 

[gaz1]

your pump should switch off via the thermostat or when the boiler is shut down via the timeclock

the only time it wont shut down is if your system is a dual heating and hotwater system the boiler will still fire up just the same but feed a hot water cylinder instead of your radiators

otherwise than that the pump should switch off when not needed

 

[dunk]

are you sure its running all the time, i had one on the old system in the last house,this did run a lot but knocked off at some point, and as had already been said the hot water tank kept it running for a long time

 

[bill_gj]

I've got the same problem - poxy pump runs forever, regardless of the demand from water or heat.
I'ts been like this since the boler was replaced by a CORGI registered expert.
I haven't got around to having a look for myself on the basis that I could make it worse during crap weather.

 

[waddycall]

What kind of boiler do you have - gas, oil or solid fuel?

 

[zx9]

I'ts been like this since the boler was replaced by a CORGI registered expert.

You need to look for 'Gas Safe' these days Bill, if he is still advertising as CORGI registered I would not be trusting him to replace a boiler. Most boilers are told to heat water by the wall or thank stat, the boiler then energises the pump, when demand for heated water ends the boiler turns off and just runs the pump for a little while to clear the recently heated water in the boiler. There can be a lot of wires to look at if you have multipal heating zones but it is not too difficult to get your head around.

 

[cardiffrob]

Thanks, guys.

It is a British Gas 330+boiler with the tank in the airing cupboard. The tank doesn't switch off with either the time clock or the thermostat. It was all replaced about 4 years ago when everything was changed following a severe pipework blowout in the middle of winter that wasn't spotted until the previous owners returned from a few months abroad!
I can spot 2 valve assemblies that have "Man-Auto" levers on top and one can be heard twirling when the time clock switches off. One valve before the rust trap and one after. Does that make sense?
The interweb suggests either a failed pump or a failed controller somewhere that ought to knock the pump off.


I should add that occasionally it fires up the bolier for a few seconds...you can see brief bursts of steam from the bedroom window above the flue.

 

[roofman]

Thanks, guys.

It is a British Gas 330+boiler with the tank in the airing cupboard. The tank doesn't switch off with either the time clock or the thermostat. It was all replaced about 4 years ago when everything was changed following a severe pipework blowout in the middle of winter that wasn't spotted until the previous owners returned from a few months abroad!
I can spot 2 valve assemblies that have "Man-Auto" levers on top and one can be heard twirling when the time clock switches off. One valve before the rust trap and one after. Does that make sense?
The interweb suggests either a failed pump or a failed controller somewhere that ought to knock the pump off.


I should add that occasionally it fires up the bolier for a few seconds...you can see brief bursts of steam from the bedroom window above the flue.

that could just be routine service mode

 

[gaz1]

it does to me yours is a hot water system and a central heating system its is controlled by a few things time clock and thermostatic control and also a hot water heating setting where hot water is only heated and not your central heating system

you should have something that looks like this



that one controls 2 things your central heating flow and also your hot water system flow and you can overide it manualy
its a motorised solenoid valve

your pump should only work when its calling for heat via 2 thermostats one on the hot water system and one at your roomstat or via the timeclock

 

[brightspark]

the one above is a 3 port valve y plan - the pump will be conected to the bottom inlet which is the flow from the boiler.if u have 2 strait through valves it will be -an s plan one valve for heating the other for water . the pump should only run on both systems if either is calling for heat. the pump-should be conected with the bo-iler switched supply and both come on together

 

[brightspark]

y p[lan

https://www.google.co.uk/search?q=y...ed=0ahUKEwiB6JSlzrvJAhXFzRQKHebyBRYQsAQILQand s plan

https://www.google.co.uk/search?q=s...X&ved=0ahUKEwiIppXxzrvJAhXDWRQKHfipDCsQsAQIHg

 

[clueless77]

If the lever on the side of a zone valve is loose without a demand from the time clock and stat/stats it could mean the valve is stuck open and holding the lever onto the microswitch and sending a live to the pump and boiler (new valve usually required) or it could be the microswitch itself has shorted so is sending a permanent live to the pump and boiler (new motorized head usually required). Alternatively it could have just been wired up wrong.

 

[normspanners]

I should add that occasionally it fires up the bolier for a few seconds...you can see brief bursts of steam from the bedroom window above the flue.

The boiler lighting for a few seconds could be the gas control valve leaking and gas sitting in the bottom, of the boiler fire chamber till it is lite by the pilot light then can ignite the gas for a quick burst, i had this situation when the plumber piped in the gas supply and didn't purge the line he had slid the pipe in the trench and filled it with sand which then got into the valve cost me hundreds in gas, as it was leaking all through the summer, they changed the valve under gaurantee that worked fine till more sand traveled up and stuck the new one, I didnt realize and went through three years with the gas leaking.
it was only when the boiler lit up as I kept coming in the back door the draft must have just lifted the gas enough.

 

[the snooper]

ive just googled this boiler and its an ideal standard boiler badged british gas, infact it looks like its an ideal classic, these can come with a header tank or a closed system, if a closed system the pump is mounted on the top of the boiler along with the expansion vessel, which system do you have ?
with this boiler you should have water and heating controls, and the pump should come on with the boiler, the timer / controller should control the divertor valve dependant on whether you have switched heating or water on but in either case supply power to boiler and pump, if you have hot water and heating on a same time the hot water will overide the central heating when the tank temp drops, i have a spare pcb somewhere for one of these boilers

 

[Shox Dr]

I wouldn't want your gas/leccy bill

 

[the snooper]

The boiler lighting for a few seconds could be the gas control valve leaking and gas sitting in the bottom, of the boiler fire chamber till it is lite by the pilot light then can ignite the gas for a quick burst, i had this situation when the plumber piped in the gas supply and didn't purge the line he had slid the pipe in the trench and filled it with sand which then got into the valve cost me hundreds in gas, as it was leaking all through the summer, they changed the valve under gaurantee that worked fine till more sand traveled up and stuck the new one, I didnt realize and went through three years with the gas leaking.
it was only when the boiler lit up as I kept coming in the back door the draft must have just lifted the gas enough.

these don't have a pilot light norm they have ignition system

 

[Seadog]

Thanks, guys.

It is a British Gas 330+boiler with the tank in the airing cupboard. The tank doesn't switch off with either the time clock or the thermostat. It was all replaced about 4 years ago when everything was changed following a severe pipework blowout in the middle of winter that wasn't spotted until the previous owners returned from a few months abroad!
I can spot 2 valve assemblies that have "Man-Auto" levers on top and one can be heard twirling when the time clock switches off. One valve before the rust trap and one after. Does that make sense?
The interweb suggests either a failed pump or a failed controller somewhere that ought to knock the pump off.


I should add that occasionally it fires up the bolier for a few seconds...you can see brief bursts of steam from the bedroom window above the flue.

Definitely not a failed pump!

 

[cardiffrob]

Great responses. Thanks.
The system has no expansion vessel and the pump is sat next to the tank upstairs.
Thermostat is in the hallway and there is a small dial-type thermostat on the side of the storage vessel. The time clock has separate sections for CH and HW in the control box and is mounted near the pump and valves. There is a (dirty water) header tank upstairs alongside the larger (clean water) header tank.
The valves (x2) have only 2 ports (S-plan?) and one of them seems to have no life. Clueless77 in post #14 might have something for me to look into. The other valve motors if I apply some pressure to the Man-Auto lever and I'd assume it is doing so in disagreement with my action?

Looking at the diagrams Brightspark suggested I now get the idea that the pump will send water to either the tank or the rads. If so, can I assume that continued rad heating after the CH timer is off will indicate that the CH valve is the duff one? This would presuppose that the pump is designed to run until the valve demands it to shut rather than being designed to switch off when the CH timer tells it to do so. Is this correct thinking on my part? Snooper kinda touched on the subject but I'm still a little confused.

Beginning to get a handle on this malarkey!