Pumped hot water loop alternative

[brig001]

Our bathroom is a long way from the megaflow tank and it takes a while for the water to run hot at the tap. No problem for filling the bath, but would be nice to have warm water available immediately at the sink

Is there a way to fit a valve under the sink piped to the toilet fill so that it would use the hot water pipe until the water came hot, then complete the fill with the cold water pipe? Wouldn’t cover every eventuality, but washing hands after using the toilet is probably the main use of the sink

Brian

 

[trojanhawrs]

That's a pretty great idea actually. The simplest way would probably to fit a second fill valve in your cistern and set it at the right height to stop when it's hot enough.

 

[Daveydub]

That's a pretty great idea actually. The simplest way would probably to fit a second fill valve in your cistern and set it at the right height to stop when it's hot enough.

 

[brig001]

That's a pretty great idea actually. The simplest way would probably to fit a second fill valve in your cistern and set it at the right height to stop when it's hot enough.

Thanks trojanhawrs, I think it could work.
I thought of a temperature switch under the sink to switch a valve between the hot and cold pipes

Quick tests:
From flush to full 50 seconds
From tap open to hot 40 seconds - sink 3/4 full - probably less than a full cistern
From standing to sink 10 seconds
From sitting to sink 30 seconds

Hmm, not ideal, but better than without
Assuming that the cistern fills at the same speed as the sink tap, you would be waiting 10 seconds for hot water instead of 40 seconds after a sit down

Brian

 

[trojanhawrs]

Don't know what your sink/tap setup is like but good chance you can have the flow faster in a cistern given it has a lid. Might be limited by the head supplied though.
It would be a lot of ****ing about to do it on temperature and pricier too, the valve would also need to know when the flush was activated. Electrics in the bathroom is a bit of a minefield anyway.

 

[brig001]

Yes, just checked and the flow is restricted to the tap - it was splashing too much so I turned it down

I’m not sure that the valve would need to know as it could be like the diverter on central heating, and switch over when hot and back when cold. Downside to that is it could retain heat and the water in the pipes could cool. With your way, you would always get hot water. Pity our cistern is so bad to get to… I need another look

Brian

 

[Harry Bloomfield]

Our bathroom is a long way from the megaflow tank and it takes a while for the water to run hot at the tap. No problem for filling the bath, but would be nice to have warm water available immediately at the sink

A reasonable compromise, is to have the circulation pump, triggered by a PIR located where the HW will be needed - in your case, a PIR in the bathroom. Someone walks in the bathroom, triggers the PIR, pump starts, and there is HW at the tap, before it's needed.

An alternative, would an electrically heated HW store, located close to where it would be used, but fed from the main source.

 

[brig001]

A reasonable compromise, is to have the circulation pump, triggered by a PIR located where the HW will be needed - in your case, a PIR in the bathroom. Someone walks in the bathroom, triggers the PIR, pump starts, and there is HW at the tap, before it's needed.

An alternative, would an electrically heated HW store, located close to where it would be used, but fed from the main source.

Hi Harry, the point of this is to achieve the same without a circulation pump or loop
It assumes that you would use the toilet before the sink, and use the cold water in the hot pipe to fill the toilet. Hot water would then be available instantly at the hot tap - hopefully

Brian

 

[trojanhawrs]

Yes, just checked and the flow is restricted to the tap - it was splashing too much so I turned it down

I’m not sure that the valve would need to know as it could be like the diverter on central heating, and switch over when hot and back when cold. Downside to that is it could retain heat and the water in the pipes could cool. With your way, you would always get hot water. Pity our cistern is so bad to get to… I need another look

Brian

You can't fill a tank that's already full though can you? You could plumb it to the drain in that case but its a bit of a waste, and also doesn't solve the issue of getting the electrics there for your solenoid.

 

[Harry Bloomfield]

Hi Harry, the point of this is to achieve the same without a circulation pump or loop
It assumes that you would use the toilet before the sink, and use the cold water in the hot pipe to fill the toilet. Hot water would then be available instantly at the hot tap - hopefully

Brian

OK - alternative idea...

Solenoid valve, PIR triggered, but with a pipe stat in series with it? PIR opens valve, which dumps water to waste, until hot heats up the pipe stat. PIR mounted in bathoom ceiling, stat and solenoid can be located anywhere reasonably close to the bathroom.

 

[trojanhawrs]

OK - alternative idea...

Solenoid valve, PIR triggered, but with a pipe stat in series with it? PIR opens valve, which dumps water to waste, until hot heats up the pipe stat. PIR mounted in bathoom ceiling, stat and solenoid can be located anywhere reasonably close to the bathroom.

As I said, a lot of ****ing about and a lot pricier. My way is a tenner for a fill valve, £20 for pipe and fittings and £10 for a tile bit.

 

[brig001]

As I said, a lot of ****ing about and a lot pricier. My way is a tenner for a fill valve, £20 for pipe and fittings and £10 for a tile bit.

I agree, but

 

[trojanhawrs]

Laughing, you already have a hole! Counter should just lift off no?

 

[trojanhawrs]

You may need to disconnect the sink if its on the same counter

 

[brig001]

Laughing, you already have a hole! Counter should just lift off no?

No, it appears to be glued - was in when my wife bought the place. Looks nice, but can’t get to anything. Certainly don’t want to risk breaking it

If I could, I would try your idea, but I think I’ll have to try a thermal switch and valve unless we get any better ideas

Thanks,
Brian