Connecting hot to WC

[SteamyTea]

8 minutes ago, PeterW said:

31 minutes ago, dpmiller said:

a wee battery powered

Is that a WC related pun

 

2 minutes ago, dpmiller said:

clamp-on appliance

 

23 minutes ago, ToughButterCup said:

body made of Tupperware

 

 

Did not take long to degenerate, well in my mind anyway.

[Dreadnaught]

5 minutes ago, dpmiller said:

I anticipate running it's drain into the basin drain through a clamp-on appliance tapping

 

Thanks. I like this solution a lot. Now, I wonder if I can convince my M&E advisor of its merits. 

 

By my calculations, a 10mm hot pipe would hold 352 ml of cold water. Or if I chose to use a 15mm pipe, and included the shower in the arrangement too, then that would hold 1-litre of cold water. 

 

Thus when you entered the bathroom a litre of cold water would go down the drain. I notice that the urinal-PIR-thingy has a settable timer so that if you walk in-and-out of the room 5x times, 5x litres of water does not head down the drain.

[Dreadnaught]

Just now, Dreadnaught said:

a litre of cold water would go down the drain

 

I wonder if that would be audible.

[Carrerahill]

1 hour ago, Dreadnaught said:

If the bathroom is a long way away from hot-water source, I recall a post where @PeterW suggested connecting the hot pipe also to the WC cistern so that flushing the toilet would pull through the dead-leg of cold water in the pipe. (I searched but could not find the old post.)

 

Is this still considered a good idea?  My bathroom will be about 15m from the hot-water source (a Sunamp).

We have this issue in our new kitchen, I say issue but we live with it perfectly well, washing hands in hot water is tap on about half way, let the water start running, wet up hands, soap, proper lather up and clean of hands, warm water is here. 

 

For a quick rinse i.e. after chopping garlic or onion or something I just use cold. 

 

If you have been at the bathroom, then you should be washing your hands thoroughly, therefore by the time you soap up you should be onto warm/hot. Are we not meant to be singing happy birthday twice or something while we wash our hands anyway? Surely 15m of 15mm(?) which is about 4.5litres of water will be flushed by then. 

[Dreadnaught]

3 minutes ago, Carrerahill said:

Surely 15m of 15mm(?) which is about 4.5litres

 

Ah, I actually calculated it for 10m not 15m. Sorry. In reality the length is about 13m or so. 

 

Note that 15mm is the outside diameter. I think the internal diameter of 15mm Hep2O is 11.3mm (wall thickness being 1.85mm).

 

(11.3/2)^2*3.15*13 ≈ 1.3 litres

 

 

[Dreadnaught]

On @dpmiller's ingenious idea of using a Urinal-PIR sensor to empty the dead-leg of water, how about a cobbled-together Smart-home solution like this:

 

- a 15mm Solenoid Valve Nylon (normally closed), 230v version, like this, £21

- A smartplug (Homekit, Alexa or Google Assistant, etc.) 

- A PIR sensor (Homekit, Alexa or Google Assistant, etc.) ← I would have this anyway for the lights. 

 

The PIR sensor triggers the smart plug, which opens the valve for a set period. Could even program it not to trigger again for a set period.

 

Why might that not work? I suspect there are some reasons.

 

The solenoid:

Edited January 28, 2021 by Dreadnaught

[willbish]

From a different perspective, is it 'right' to design something into your house that is going to chuck litres of fresh water down the drain everyday the house is occupied for years to come?

 

We are blessed with ample rainfall in this country but droughts are not uncommon.

[dpmiller]

using that logic, why heat the water at all, it's wasting energy to so do...

[willbish]

@dpmiller not really, hot water is a necessity for hygiene.

 

[Tennentslager]

Walk into toilet

Turn on tap

Sit on pan

Whip phone out of back pocket

Surf Buildhub

Wash hands

 

 

 

 

 

 

 

 

[Onoff]

Walk into bathroom...

 

[JFDIY]

Think I suggested feeding the cistern with hot water. I've had this set up for 10years in my bathroom.

 

It's a TMV fitted after the hot spur to the basin tap, TMV set at around 25-30⁰ (basically water in a hot summers day)

 

When you repeatedly flush the toilet the water in the cistern is best described as tepid. I get no condensation and the water you'd normally waste down the sink is mostly eliminated.

 

I intend to do the same in the kitchen on the feed to appliances, to speed up hot water availability at the tap as the kitchen is a long way from UVC and it  reduce cycle times of the appliances + cost of heating  the water with gas v's electricity is cheaper

 

[Onoff]

My bathroom is a country mile from the hot water cylinder so taps take an age to get hot. I think I've missed the boat to include a pumped return on the sink hot?

 

Up in the loft I've this (unconnected one is now mains cold to the sink). Hot comes from the cylinder many metres away:

 

 

Drops down, hidden in the wall, (no joints) to this:

 

 

The WC is currently mains fed. If I'm reading this thread right, I could jump that instead into the hot. Flushing would pull a slug of water in the hot pipe through. Thus when you turn the sink on you've less time to wait for it to become hot? That initial "cold" slug you pull through to flush the WC would otherwise be wasted running the sink until it gets hot.

 

The kids are always complaining the sink is cold when they wash their hands. This might encourage them to actually flush the loo!

[ProDave]

How about a manual "purge" button. So ONLY when you are expecting to use the basin, press the button and it will dump water down the drain until it senses the hot water has arrived.

 

No waste dumping water when you don't want to use it, and no different to you just running the tap manually until you feel hot water has arrived.

 

It would not be difficult to see that able to be packaged as a commercial product.  Hmmmm................

[SteamyTea]

13 hours ago, Tennentslager said:

Walk into toilet

Turn on tap

Sit on pan

Whip phone out of back pocket

Surf Buildhub

Wash hands

I always fell dirty after reading hub sites.

[Russdl]

13 minutes ago, ProDave said:

How about a manual "purge" button. So ONLY when you are expecting to use the basin, press the button and it will dump water down the drain

you could call it...

 

a tap! ?

 

@Dreadnaught you mention having to convince you’re M&E advisor on the merits of an alternative system to the hot return loop. Just TELL him that is what you’re having.

 

You mention you’re using a Sunamp so  you’re M&E advisor is clearly already comfortable with some less than conventional elements of your design so he should be able to manage an alternative to a hot return loop.