Disabling hot water secondary circulation

[j-123]

Hello, we've just moved into a new house. The hot water system has secondary circulation. The pump has been installed without any control so it is on 24/7. I've never had a house with this set up before and wouldn't have thought it necessary given the size of the house.

At the moment the pump is noisy enough that you can hear it at night time in one of the bedrooms (it's in the loft just above). This may be due to the installation position as it is up against one of the beams. If we're not bothered by with the delay in hot water can I disable the secondary circulation by just removing power to the pump? Would I need to do anything else, is there something I should be aware of, is this not a good idea?

Any advice, much appreciated.

 

[ianmcd]

yes just disconnect the power, there are better ideas though, like PIR control of areas when you would want the secondary pump to run, but if you just want to stop it remove and safely isolate the live wire to the pump

 

[j-123]

Thanks for the reply. I'll disconnect for now but will investigate control options. In the two days we've been in the house, the hot water does seem to lose temperature pretty quickly. With the boiler going off in the morning the water is lukewarm by late afternoon (with no hot water use during the day). Are secondary circulation systems pretty inefficient - is that to be expected or are the pipes perhaps not well insulated? It's a modern well insulated tank so I'd expect the system to keep heat better otherwise.

 

[oldbutnotdead]

I'd suspect it's the hot water pipes that aren't insulated or only have thin stuff on. As above, just disconnect (safely) the pump and see what the difference is. Just out of curiosity, have a look at the colour of the pump body & see if there's a make/model- there are clever secondary pumps that have internal control circuitry to 'learn' hot water use patterns

 

[j-123]

Thanks. I've disconnected the pump. Now on some of the furthest taps it does take quite a while for the water to come through at full temperature from cold (approaching 2 minutes).

The pump is a Wilo SB30. I had a quick look - the pipe runs I can see in the loft are plastic with no insulation. At the taps I've checked the pipes are plastic coming out of the wall. Plastic will be better insulating than copper but presumably it's still worth insulating where I can (particularly in the loft)? Interestingly I've also gone through the box of documents the previous owner left. One of them is the architect's specification for the renovation which they did 10 years ago. This included re-plumbing and the spec was for all hot water pipes to be insulated.

 

[ianmcd]

yes you have to insulate the pipes pe or copper

 

[j-123]

Thanks for your help. Another job for the list.

 

[oldbutnotdead]

Placcie pipe isn't a lot better than copper in terms of heat loss. And the couplers are really boring to insulate completely. 2 minutes- you'll start noticing that if you're on a water meter , not to mention the irritation.

PS At least they used the correct type of pump. Rigging control would be very easy these days with WiFi everything available....

 

[j-123]

Yes, it's not ideal is it?! Other taps aren't nearly as bad though. First step is to insulate the pipes to see what difference that makes and then I'll look at better control options as suggested. The insulation is going to be easy enough in the loft but not quite sure beyond that.

 

[oldbutnotdead]

Mmm, floorboards a go go. Since the house is new to you, best bite the bullet and do them now, while you're at it do the cold pipes (so you aren't brushing yr teeth with lukewarm water )

 

[j-123]

That's the bit I'm worried about. Engineered wood floors throughout so that would be a major pain. I think all the hot water pipes drop straight down from the loft. I need to check the heating pipes too. With the boiler on to heat the water the (uninsulated) pipes are hot at the underfloor heating manifold which is in a cupboard in another room from the boiler. Not great in the summer!

It's quite confusing. The previous owners spent a lot on the renovation to make the house energy efficient (solid wall insulation, roof and floor insulation, high spec windows, heat recovery system) but didn't insulate the pipework

 

[oldbutnotdead]

Insulating the heating pipes in 'cold' areas (loft, under ground floor, that sort of thing) makes sense. Insulating them in warm areas is less useful- the heat 'lost' from them is warming habitable spaces so it isn't truly wasted. Though it can be a pain- one house I lived in the cats would sleep on the landing cos the pipework to cylinder etc kept the floor nice and warm

 

[Laurieo]

Don't think plastic pipe should be used for continues flow hot water, except for loops to tap. Lots of other threads on here about this ,

 

[oldbutnotdead]

Don't think plastic pipe should be used for continues flow hot water, except for loops to tap. Lots of other threads on here about this ,

Oh yeah, forgot about that. Think Hep2O is OK for it but not generic barrier pipe, well remembered

 

[MeldrewsMate]

Think Hep2O is OK for it but not generic barrier pipe...

Not wishing to hi-jack your post, but what is the objection to using barrier pipe on secondary hot water systems?

OP: Consider using a simple programmer combined with a pipe mounted 'stat so that the time of operation for the secondary circulator could be controlled, and automatically turned off when hot water is returned to the cylinder....so it's only noisy just before you start using the hot water.