Pipe thermostats and pumped HW

[Stephen]

Hello,

I was thinking of converting my HW to a pumped system because I'm fed-up of waiting ages for hot water to come out of the tap!

I understand I need a pump with a bronze impeller: are there any available for under £100?

AIUI the pump is controlled by a pipe thermostat. I have had a look at the instructions of the Horstman cylinder thermostat and it says it can be used as a pipe stat on pipes of 28mm and above. Presumably to give a sufficient surface area for heat transfer but I was only going to use 15mm pipe. The Honeywell cylinder thermostat instructions do not mention anything about use as a pipe thermostat.

Will all 'stats require 28mm pipe or will any work with pipes of smaller diameters?

Using a short length of 28mm pipe with a 15 to 28 reducing coupling is one way around it but it seems a waste to have to buy a length of 28mm pipe just to use a couple of inches of it.

When I get hot water to the taps I wonder whether I might have the opposite problem of the water being too hot! AIUI the water has to be

60C to kill bacteria so is the only answer to have thermostatic mixers at each tap to cool the hot water down to say 40C?

Thanks, Stephen.

[Roger Mills]

Are you sure that the pump is controlled by a stat? Shower pumps serve a similar purpose, and they are often controlled by a flow switch. As soon as a tap is opened, there is *some* flow - by gravity - and this is enough to trigger the flow switch to make the pump cut in.

[John]

Are you meaning a pump to increase the pressure - or a pump to circulate water around a domestic ring to avoid dead legs?

[John]

By Ring - I think I meant Hot Water Recirculation

[Roger Mills]

I was meaning the former but - on re-reading the OP - maybe that was about the latter.

[Stephen]

Sorry if I was not clear; you were right first time. It takes forever for hot water to get to the downstairs taps, so I just want to circulate hot water around the pipe work to get instant hot water; there's no need to increase the pressure AFAIK.

[Roger Mills]

In that case, I wasn't right! I was talking about increasing the pressure - or, more precisely, the flow rate from cylinder to tap - rather than about constant circulation.

[Rod]

Why do you have this problem? Is your pipework extra long or large diameter?

Just asking because there might be feasible alternatives - such as replumbing in 10mm pipe.

[Stephen]

Sorry for the delay in replying: just a long, un-lagged, pipe run to the kitchen from the cylinder upstairs. The pipe goes into the concrete floor so I cannot easily access it to lag it. It's 15mm.

[Rod]

Doesn't sound promising for any alternatives I could dream up. :-(