Any Plumbers here?

I'm busy renovating a 75 year old bungalow thats had 40 years of the previous owners coming up with ingenius ways of stuffing things up. Just about sorted on everything else and now its time for the plumbing. My usual plumber is off of holidays so I need a bit of advice.

When the old guy that lived here put the cold water tank in the loft he's only left a head of about 4" between tank full and the outlet for the cold water. The hot water tank feed is 1" below that leaving 8" of water redundant in the bottom of the tank. If you run a bath, the tank runs out of supply and can't keep up, which drains the whole system and it's a bugger to refill. Airlock city!

Is there any reason I can't bypass the tank for the cold water feed and have the house run directly of the main supply for the cold water system and leave the tank in place as the feed for the hot water tank? And if this is possible do I need to fit a pressure reduction valve?

Thanks in advance,
C

So you a cold feed from your tank to your bath cold tap? am i reading that right?
Unless you have a mixer, run direct to tap from mains pressure will be fine, id sort the tank out tbh as well.
Put another outlet further down the tank so it has more capacity.

yes you can plumb to main supply no problem.

you would need to adjust or change the ball vave to the toilet. (hp insert)

be aware if you have mixer taps bath or basin due to unequal pressure may require check valves

depends on incoming pressure and flow rate, you could fit a pressure reducer to balance the water for bathroom

forgot if the incoming supply is good enough fit a 3/4 ball valve, this will allow the tank to fill quicker

Thanks gents,

Bypass the tank and fit a pressure reduction valve looks like the way forward. Fitting another outlet to the tank further down would require somone 3 ft tall with arms like popeye and they aren't that common, Its a tight squeeze in there.

Cheers,
C

Originally Posted by Berlin

Thanks gents,

Bypass the tank and fit a pressure reduction valve looks like the way forward. Fitting another outlet to the tank further down would require somone 3 ft tall with arms like popeye and they aren't that common, Its a tight squeeze in there.

Cheers,
C

You dont have to fit a PRV, only if you have a mixer shower /tap, unless you have ridiculous amount of pressure coming in.
I go in way more houses set up like you wanna set yours up than the way it is now.

[andrewsmith]

as specialone

Sounds like new build houses

There is a mixer tap for the bath/shower.

Any reason can't I do away with the tank completely, fit a 3 bar pressure regulation valve and run the whole house from the mains?

It'd mean running the overflow from the hot water tank to the outside (instead of back into the tank) but that's not a big deal as I could use the overflow from the tank.

C

[embee]

You can't run a vented hot water cylinder as an unvented, they're not made for it. Also on the bureaucratic niceties, changing a hot water storage vessel larger than 15(? not sure about that) litres is notifiable, and if it's unvented you need to be registered I believe.
I'm sure "some" people ignore the bureaucracy.

It's not good practice to have a water take off half way up, you ideally want to ensure good circulation in the tank, I've seen additional parallel cold water tanks fitted to overcome the bath problem you describe and then the inlet should be in one and the outlet in the second ideally to ensure through-flow. I've also seen two 15mm (1/2") ball-valves fitted in a single tank (if you think the valve is the restriction).

If you can bodge things you could fit a siphon tube inside the tank to the existing take off, so that it will continue to run even as the water level drops below the outlet height until the bottom of the siphon gets uncovered. Probably not a satisfactory solution but a simple bodge. Keep teh siphon entry 50mm or so clear of the floor of the tank to avoid taking the crud and dead pigeons into it.

Sounds like a refit might be in order. Have you got rid of all the lead pipe?

I'm liking the syphon idea. Thats a very simple fix!

I won't be touching the hot water tank, just the cold water tank upstairs.

Thanks for that,

C