Central Heating Pump

[chookey]

My pump runs 24 hours a day. Been like this since it was installed 2 years ago.
It never bothered me before but having just paid a scandalously high electric bill I am looking for ways' to economise.

There is no room thermostat and all but the bathroom radiator have TRV's fitted.
Does a room stat turn the pump on/off? Looking at the manual the stat connector has a wire bridge between 2 terminals, is this the cause of the ever-running pump?
It has to be removed if fitting a room stat so would seem logical but I know zilch about central heating.
The boiler is a Riva Compact HE MK2

 

[Him Her]

Your installation sounds similar to good practice for the time but Building Control etc. are now saying a room stat should be fitted even where there are TRVs.

The link is the likely place to install - as you suggest, remove the link and insert a stat connection.

However, I don't think this is your problem unless the boiler is running at the same time as the pump. Normally, the controller would fire the boiler and the pump at the same time. I would check whether there's something additional - is the boiler in a cold location (garage). If so the frost protect system could be at fault.

 

[chookey]

The boiler is in my kitchen. I can't recall for certainty that it has ran continuously since the install but reasonably sure it has.
I reckon the best bet is to isolate it, remove the link and pop some cable in it. Temporarily short the cables to fire it up and then open the circuit and see if the pump stops.
No idea if the connector is 240v or low voltage from the pcb's transformer though.

Don't want to spend on a stat and still have the same problem

 

[Him Her]

Gonna be 230v M8 so watch fingers! Do you know the revision of the boiler - just in case there's a difference? I'll have a look at the wiring diagrams...

Hang on, think that boiler has a connector so you can unplug the boiler. If the pump still runs it's a wiring fault, if not probably a pcb fault. Pray it's a wiring fault 'cos the pcb costs...

 

[baron]

It sounds to me like a fully pumped system the bathroom radiator is the bypass radiator this radiator is across the boiler you have to maintain a certain amount of flow through the boiler or it will constantly shut down if the trvs all shut off the bypass keeps flow through the boiler that would explain why the pump is running at all times when the boiler is on...... unless some one knows different

 

[chookey]

Gonna be 230v M8 so watch fingers! Do you know the revision of the boiler - just in case there's a difference? I'll have a look at the wiring diagrams...

Hang on, think that boiler has a connector so you can unplug the boiler. If the pump still runs it's a wiring fault, if not probably a pcb fault. Pray it's a wiring fault 'cos the pcb costs...

Cheers HimHer, M96A.24SM/C

 

[wiz569]

Dont really want to comment too much as its difficult when you cannot see the installation in question,
but in my 30 ish odd years,as a plumber, I have never seen,or know of, a reason that a pump should run 24/7/365 unless its wired wrong or there is a fault

 

[chookey]

Dont really want to comment too much as its difficult when you cannot see the installation in question,
but in my 30 ish odd years,as a plumber, I have never seen,or know of, a reason that a pump should run 24/7/365 unless its wired wrong or there is a fault

The only time the pump stops is when I either switch the heating off via the front panel or during a timer operation.
Gonna whip the front off and slide the pcb out tomorrow morning and have a look.

 

[wiz569]

The only time the pump stops is when I either switch the heating off via the front panel or during a timer operation.
Gonna whip the front off and slide the pcb out tomorrow morning and have a look.

Ok so if the pumps switches off when the heating timer switches off then thats normal,unless there is another reason like calling for hot water,and not what you describe in your original post,
or am i misunderstanding you?

 

[Rumpelstiltskin.]

I'm not sure either anymore?

 

[chookey]

What I mean is that when the call for hot water to be pumped round the system ends, the pump carries on running. I realise that the pump may carry on for a short while when the boiler is hot, but surely it shouldn't be running all the time?

 

[Him Her]

What I mean is that when the call for hot water to be pumped round the system ends, the pump carries on running. I realise that the pump may carry on for a short while when the boiler is hot, but surely it shouldn't be running all the time?

The bathroom radiator is the 'shunt'. The boiler on-board controller should run the pump for a while to take the heat away from the boiler via the bathroom rad. The boiler plug should be behind the inspection panel towards the bottom left if it's the boiler I'm thinking of and the boiler on-board pcb controls the pump. As Wiz says, be pretty odd for a pump to run 24/7 - I'll check the numbers you posted but all the boilers I've seen in that range use the same electrics...

 

[wiz569]

What I mean is that when the call for hot water to be pumped round the system ends, the pump carries on running. I realise that the pump may carry on for a short while when the boiler is hot, but surely it shouldn't be running all the time?

Ok but you said it stops running during a timer operation?

So are you sure its running 24/7?

If so then its either wired incorrectly or there is a problem on one of the PCB boards,but I'm guessing you already have worked that much out lol

 

[Him Her]

I'm gonna wait to see what the answer to Wiz is. Pulled the manual and it's less than clear without the system in front of me - probs need a heating engineer to visit...

 

[JimmyP]

Major pump overrun lol has anything changed on the system recently

 

[JimmyP]

Having a quick read this boiler is a biasi combi is that correct chookey?

 

[chookey]

Thanks for the help guys, will post back tomorrow after I've tested the thermostat connector.
I'm confused as well now, beginning to doubt its' a problem and this is normal operation. Will know more tomorrow.

 

[baron]

Have you got a cylinder stat and is it set higher than the boiler temp

 

[chookey]

Major pump overrun lol has anything changed on the system recently. Having a quick read this boiler is a biasi combi is that correct chookey?

Have you got a cylinder stat and is it set higher than the boiler temp

Sorry I missed these posts lads. It is a biasi Jimmy but nothing has changed as you will see at the end of this post.
baron..I haven't checked that as I have proved what I suspected to be the reason for the pump overrun.

I whipped out the control panel this morning to gain access to the external controls connector and removed the link. I connected 2 wires in place of the link and shorted the other ends together and fired the system back up.
Gave it a minute or so and broke the connection, within a few seconds the boiler stopped and the pump ran on for 5 seconds or less. So, as I suspected the wire link was giving the pump a permanent feed.I'll fit a room stat and start saving electricity, lol.

Thanks to all

 

[wiz569]

Sorry I missed these posts lads. It is a biasi Jimmy but nothing has changed as you will see at the end of this post.
baron..I haven't checked that as I have proved what I suspected to be the reason for the pump overrun.

I whipped out the control panel this morning to gain access to the external controls connector and removed the link. I connected 2 wires in place of the link and shorted the other ends together and fired the system back up.
Gave it a minute or so and broke the connection, within a few seconds the boiler stopped and the pump ran on for 5 seconds or less. So, as I suspected the wire link was giving the pump a permanent feed.I'll fit a room stat and start saving electricity, lol.

Thanks to all

Did the boiler stop as well when you broke the connection ?
Or had you turned it off at the timer first?

sent using my telepathic powers