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...