CH HW Q

[tpow]

My father in law is away from his home for a while and I decided to reduce his house central heating ON/OFF times during this period. Currently he has it running ON day and night, HW & CH...........

I now have both water and heating coming on for 1/2 hours morning and evening just to keep it ticking over. Even though the system is OFF with boiler definitely shut down, the pump still runs. It is not running water around the CH system but just circulating it around the local HW tank pipework but not via the boiler.

It is a Sentinel Housing property and the heating system was installed/upgraded a couple of years ago to bring it up to current standards and legislation.

So is this the modern way, with the pump continually running.

thanks dj

[Dave Plowman (News)]

Why? It's pointless heating an empty house - or the water.

Sounds like a bodge, or the microswitch in the 3 way valve has failed, or the valve stuck.

No. My ultra sophisticated ;-) new boiler runs the pump for a short time every 24 hours even when set to standby (only frost protection, no heating or hot water) to prevent it seizing up. Anything else is just wasting power.

[David Hansen]

On Sun, 6 Jul 2008 09:37:01 +0100 someone who may be "tpow" wrote this:-

Possibly not. If the pump is running continuously then they have failed the economy of operation tests.

However, the fact that the boiler is not firing does not mean that the pump will not run. The pump is likely to run for a while after the boiler goes off. How long "a while" is depends on the system, the installation and the conditions. Something up to 20 minutes should cover the majority of installations, but not all.

How do you know that the water is being circulated round the cylinder, but not the boiler? Is there some sort of mixing valve? Having gone through the coil in the cylinder where does the water go?

[tpow]

expansion tank and an anti fur device around one pip etc.

The pump is running all day all night...........well it is running whenever I leave the property and return at any time.

3 Way seems to be working OK not stuck.

The pipes local to the tank are hot. No other pipework leaving the airing cupboard is hot.

regs dj

[Roger Mills]

Are you sure that it's the central pump which is running, and not a separate pump which is circulating hot water round the hot taps so that they run hot as soon as you open them?

[tpow]

now that could be a valid point. It is a single level accommodation (bungalow) and there would not be enough gravity head to supply hot water to the taps.............hmmmmmm a thought.

[Andrew Gabriel]

I would turn off the HW, turn on the CH continuously and set the room stat to 10C. That way nothing should come on unless it gets quite cold. If it's an old house, 10C might be too low to stop it smelling damp, in which case increase it up by experimentation.

As others have said, no. Does the house have a roomstat anywhere? Also, do the radiators have thermostatic valves fitted?

[Andrew Gabriel]

My Keston C25 allegedly does this too, although I've never noticed it. The mid-position valve is under the control of my home automation system, this operates it once every 24 hours if it hasn't needed to do so as part of the heating operation. (It selects between upstairs and downstairs heating zones in my case, not HW and CH.)

[dennis]

That would be silly. It would be cheaper to fit electric storage heaters next to each tap.

[David Hansen]

On Sun, 6 Jul 2008 10:19:53 +0100 someone who may be "tpow" wrote this:-

Where is the pump pumping the water round? From the descriptions it sounds like the pump is pumping water through the valve and then through the cylinder. After it comes out of the cylinder how does the water get back to the pump inlet without going through the boiler?

[geoff]

In message , tpow writes

Who knows, you haven't said what make and model of boiler

why do you want DHW and CH in an empty house in the summer ?

[geoff]

In message , Andrew Gabriel writes

Or is it e.g. a Baxi Solo 2/3 in it's favourite failure mode ?

[tpow]

Going to have Sentinels heating engineers take a look..............