Cistern condensation

keystone

Bilbo44 wrote: »

Our plumber was reluctant to use one of those blending valves, because he'd not seen one before and was concerned about avoiding cold (or hot) water feed-back into the hot (or cold) pipe.

Well they are universally fitted in hospitals, hotels and public washrooms to prevent accidental scalding. There are cheap ones and expensive ones. In their latest marketing communication CORGI are offering one for around £ 30 - can't remember the exact number but its easy to pay twice or even three times that amount. They come with NRVs included and filters as well. Also to be found under the title Thermostatic Mixing Valve. Surpised he's never heard of one nor prepared to research but there we go.

So, our solution to warm-air condensing on the cold surface of the toilet-cistern, and soaking the floor, has been to install 'double-check valves', a.k.a. 'non-return valves', along with gate-valves on both the hot and cold supply pipes, joined at a tee-piece into the pipe heading for the cistern.

So what he's done is to build you a manual blending valve rather than an automatic thermo one. Single check valves would have sufficed.

Cheers

keystone

Bilbo44 wrote: »

..........at the stop-!!!! under the stairs...........

Type it all as one word stopcock and the forum censor won't think you are being rude.

Cheers

Bilbo44

Thanks for that extra info. I'll tell our (young) plumber!

BillC

Bilbo44

keystone wrote: »

Well they are universally fitted in hospitals, hotels and public washrooms to prevent accidental scalding. There are cheap ones and expensive ones. In their latest marketing communication CORGI are offering one for around £ 30 - can't remember the exact number but its easy to pay twice or even three times that amount. They come with NRVs included and filters as well. Also to be found under the title Thermostatic Mixing Valve. Surpised he's never heard of one nor prepared to research but there we go.
So what he's done is to build you a manual blending valve rather than an automatic thermo one. Single check valves would have sufficed.


Well, yes, but I think we're maybe going round in a circle here. The TMV's on offer at plumbers' merchants will prevent scalding, and are designed to cool water down to about 30-40 degrees C, but I was looking for something that would warm the water up to about 15-20 degrees C, so the anti-scald type surely wouldn't do the job - unless I wanted a really warm cistern.
Next time, I'll think I'll go for one of those "anti-sweat" valves from the USA!

lukeinman

we always had the same problem but when we had our new bathroom installed the plumber removed the cistern lid to the new toilet permanently , this has completely stopped any and all condensation from forming on the cistern, I dont know how but it has. Ours is a hidden cistern so you cant see it on a day to day basis-i wouldn't recommend doing this if the cistern is on display.