Any advice gratefully received!

[SuperMarryO]

I have recently replaced my bathroom suite as a novice plumber. There are no leaks and everything works apart from these two issues:

When I fill the bath with both hot and cold water running on mixer tap, after a while the overflow pipe outside is gushing out water? I will try to ad a picture or video of this to help.

My new mixer tap now has a very poor flow from the hot tap.
The tap is rated for medium pressure and I have tried covering the head with my hand whilst running both hot and cold to remove any potential airlocks.

I have a regular boiler (not combi) and have a hot water cylinder in the cupboard upstairs. The system is gravity fed.

I am wondering if any of this is linked to when I initially shut everything down and drained down the water to allow me to work on the new plumbing. Any help or advice would be gratefully received please. I thank you in advance for taking the time to respond to my questions.

 

[Paulplumb]

Replace the bath taps for to separate taps with the old fashioned style wind down heads not lever taps. The cold water is over powering the hot water and heading up to the tank in the loft overflowing it.

 

[snowhead]

For the time being just run Hot or Cold separately.

 

[Riley]

Or fit a non return valve on the hot side but it sounds like your tap isn't not suitable as above

 

[jtsplumbing]

If you have used flexible connections to taps make sure they are not kinked, And replace taps with full bore one's for low pressure systems

 

[SuperMarryO]

I had the old style taps on originally which worked fine but I wanted to update with the rest of the bathroom. I'm reluctant to go back to old style again. Is there anything else I might be able to do instead? Thank you very much for the advice.

 

[SuperMarryO]

Thank you I'll try that.

 

[SuperMarryO]

Thank you I will try a non return valve and see how that goes too.

 

[jtsplumbing]

Is the cold on the bath fed from mains or the roof tank ??

 

[SuperMarryO]

I'm not actually sure but I would say it was mains fed. Is there a way I could easily find out for sure?

 

[SuperMarryO]

I'm not actually sure but I would say it was mains fed. Is there a way I could easily find out for sure?

 

[SuperMarryO]

 

[SuperMarryO]

 

[SuperMarryO]

 

[clarky101]

15mm cold is more than likely mains water, maybes cut a bit of pressure by closing the ISO valve a bit & put a NRV on the hot...

 

[rpm]

15mm cold is more than likely mains water, maybes cut a bit of pressure by closing the ISO valve a bit

Edited.

 

[johnf]

The way to find out if it is mains would be to turn the stopcock off on the incoming mains. If you get no cold flow at the bath then bingo, its mains cold!

 

[SJB]

Cold mains backfilling the DHW system as others have said, bad choice of taps, a check valve will totally kill the flow from the hot side. Change taps or change the DHW system.

 

[SteveWannadoGas]

this is a useful practical lesson, one you`ll probably learn from. Good luck.

 

[SuperMarryO]

Thank you for the advice. In your opinion is it not even worth fitting a NRT to the hot then because it will simply reduce the flow further?

 

[SuperMarryO]

Thank you

 

[SteveWannadoGas]

can you not simply run a gravity cold to the tap? both sides equal pressure?

 

[Scott_D]

can you not simply run a gravity cold to the tap? both sides equal pressure?

In a finished bathroom would probably be difficult
New taps or use one side at a time

 

[ShaunCorbs]

Thank you for the advice. In your opinion is it not even worth fitting a NRT to the hot then because it will simply reduce the flow further?

either that or fit a pressure reducing valve after the shower t and crank it down to same pressure as hot

 

[SuperMarryO]

Thank you everyone, these are all interesting ideas but I'm guessing by the sound of it, although there seem to be ways of stopping the cold water flowing back into the hot there doesn't seem to be anything I can do about increasing the hot water pressure enough to be able to run a bath apart from changing the taps to something more suitable for the current pressure it seems?

 

[mfgs]

You need low pressure taps to suit the gravity hot water set up

 

[Riley]

To be honest mate. The simple answer that is unless you are going to do it properly anything else is going to be a bit of a bodge. It'll do the job but it's not how it should be

 

[dancinplumba]

There is seriousl cross contamination going on here, you need to call in a professional plumber, there are water regs being broken here. No an Nrv is not sufficient

 

[SuperMarryO]

Thank you at least I know the way forward now and there are things to be learnt. Thank you aprreciate it!

 

[SuperMarryO]

I'll look into that then thanks again