Central heating question

[JonRA]

Hi All

I am hoping someone can explain something in my new to me (6 year old) house's central heating system that I am not sure about.

The system is powered by an oil-fired boiler (which seems to be working fine, but something I haven't had before)
Downstairs there is a timer control for turning on and off the downstairs heating, the upstairs heating and hot water.
On the ground floor there is a single thermostat, plus individual thermostats on each radiator. There is a similar arrangement upstairs.

So far so good.

But there is a circulation pump running 24/7 - when I asked the previous owner, he said that 'yes, it runs all the time'

In the airing cupboard by the sealed water cylinder, there is another control which has four settings - Cont(inous) Once, Auto, Off - it is set to Continuous.

If I select Off the pump stops.

I am not familiar with this sort of second control unit in a system and would prefer the pump not to be running 24/7 (even though water from the hot taps arrives instantly, presumably because it is being circulated all the time) Pumps in my previous systems seemed to start when needed, which seems to be the norm.


Can anyone explain why this is set up like this and what the implications of choosing different settings might be? Is the oil-fired boiler a factor?

Many thanks in anticipation

Jon

[lewie]

That’s not a controller for an electric immersion is it? To be used should the oil fired system fail or stop?
Btw I’m not an expert

[Kingstepper]

Probably for the reason you allude to - so that hot water is available immediately. Don't think unique to oil-fired but due to size of house where large house might have the hot water continuously circulating in a loop rather than just heated on demand or in a storage tank where they'll otherwise always be a significant delay.

[lewie]

The pump could have been installed to negate a dead leg where there may be some delay in the hot water reaching the furthest point in the house causing it to significantly cool before reaching the tap

[jpjsavage]

A back up system?

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[Mr Pointy]

As has been said it's a continuous loop hot water recirculation system where there is a return pipe from the furthest HW tap back to the HW tank. A pump circulates the HW round the loop so you don't have to wait for it to reach the tap like a normal system:

http://www.megaflo-unvented.co.uk/se...irculation.php

The pump control could be re-wired to include a timer so it only ran for a certain part of the day, or at least doesn't run at night. Some of the Grundfos pumps have an auto adapt feature that is meant to "learn" the useage pattern but that sounds a bit hopeful to me.

https://www.grundfos.com/market-area...rculation.html

Have you tried the "Auto" position on the control?

[Craizeehair]

^^^^ This, often on for timed settings on the ‘auto’ setting to come in during peak times of use.

[JonRA]

As has been said it's a continuous loop hot water recirculation system where there is a return pipe from the furthest HW tap back to the HW tank. A pump circulates the HW round the loop so you don't have to wait for it to reach the tap like a normal system:

http://www.megaflo-unvented.co.uk/se...irculation.php

The pump control could be re-wired to include a timer so it only ran for a certain part of the day, or at least doesn't run at night. Some of the Grundfos pumps have an auto adapt feature that is meant to "learn" the useage pattern but that sounds a bit hopeful to me.

https://www.grundfos.com/market-area...rculation.html

Have you tried the "Auto" position on the control?

Thanks all for your contributions - and especially for this continuous loop info - I will investigate the auto option and also see what timer settings are on the 'Once' option.

ATB

Jon

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[JonRA]

Quick update... It seems that the pump going 24/7 was there to enable instant hot water whenever you turn a hot tap on. I have left it off and when you turn a hot tap on there is a lag before any cooled water in the pipe is flushed through and hot water flows, but it isn't an unreasonable time so I will leave the pump off most of the time.

It does explain why the house felt unnaturally warm - even though the heating was off, there was a long run of hot water circulating throughout the house 24/7 (I might turn it back during the coldest winter months)

Thanks again for your input.

ATB

Jon

[Rob Leeds]

What colour is the pump.

[JonRA]

What colour is the pump.

I'm not at home at the moment but I think it is just 'metal coloured' (ie not painted) - brass/copper?

[Maysie]

What colour is the pump.

Probably glowing orange due to the amount of work it is doing!!

[Kingstepper]

Quick update... It seems that the pump going 24/7 was there to enable instant hot water whenever you turn a hot tap on. I have left it off and when you turn a hot tap on there is a lag before any cooled water in the pipe is flushed through and hot water flows, but it isn't an unreasonable time so I will leave the pump off most of the time.

It does explain why the house felt unnaturally warm - even though the heating was off, there was a long run of hot water circulating throughout the house 24/7 (I might turn it back during the coldest winter months)

Thanks again for your input.

ATB

Jon

Good idea for winter - if heating the house slightly your rads will be on slightly less.

[JonRA]

Probably glowing orange due to the amount of work it is doing!!

LOL - but no change of colour even when it's off

[JonRA]

Good idea for winter - if heating the house slightly your rads will be on slightly less.

Yes - and not having to wait for the shower to heat up will be a cold-weather bonus too

[Rob Leeds]

I'm not at home at the moment but I think it is just 'metal coloured' (ie not painted) - brass/copper?

If it's a bronze colour or similar then it is a secondary circulation pump just for the hot water.

[JonRA]

If it's a bronze colour or similar then it is a secondary circulation pump just for the hot water.

Yes - thanks Rob

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[Kingstepper]

They are sometimes painted though...