Poor hot water pressure on gravity fed system

[Bhoydavid]

Hi all. Got a job on and hw is gravity fed. Renewed bathroom but we had to take the hot into the basement and bring it back up into bathroom (couldn't avoid it really) and cylinder is in the attic but since doing so the pressure has worsened so much so that new mixer shower won't work. Would fitting a pump on the hw solve the shower issue and rest of the bathroom pressure? Thanks

 

[WHPES]

No, unlikely. You will end up with other problems. What you describe is a bodge up and unlikely to ever work successfully.

You need to take a hot tapping directly off the cylinder and a cold feed from the cistern solely to the shower.

Do you mean the cold feed comes off the rising main? If so it will never work properly anyway.

There is either a right way or a wrong way to do things, and to try a bodge up afterwards seldom works. Your best bet if you cannot easily get a hot feed to the shower is to replace it with an electric one fed off the rising main.

 

[Centralheatking]

I know its basic but did you check the hot water flow/pressure first ?

WHPES is right - I would put a new flange (surrey/essex) straight on to cylinder
this will give flow and balance the hot/cold. Centralheatking

 

[Bhoydavid]

Yeah forgot to mention hw pressure was poor throughout house before we went in. Her cylinder only has one hot feed coming off it feeding kitchen, 2 en suites and a bathroom.

Custard doesnt want want is touching the cylinder she's happy as it is so
only option would be a pump really. Pump on the hot at cylinder and PRV on the cold at shower? Is that an option? Not long time served and my apprenticeship was mostly working in combi houses

 

[Master Plumber]

Whilst your client may not want you to touch the cylider the advice given to run new hot and cold supplies to the shower is the proper way to do it. In that the supply pressure was poor beore you started work would suggest an inherent fault in the system to start with and introducing a pump and PRV is really not the answer. In some ways you are between a rock and a hard place and the only way to keep yourself right is to do the job by the book. You may need to refer to the manufacturer's installation instructions for justification for your decision as I am sure they will require connection in this manner.

 

[WHPES]

Walk away. Not worth the hassle. Can't be done without touching the cylinder or when someone opens a hot tap the shower will be all over the place. Same with cold. Supplies must be independent. Bodge up, especially with what you suggest on the cold. Chances are it won't work properly and you won't get paid or you will be badmouthed to others about it.

Imagine taking your car to the garage and saying "I can't seem to get enough acceleration out of it but I dont want you touching the engine".

You need a cold feed directly from the cistern and a hot feed directly from the cylinder. End of! Anything else is a bodge up!

Did you also check the cistern was Water Regulations compliant before the shower was put in (close fitting lid, seals round vent pipe, dip pipe, breather, insect screen?)

 

[WHPES]

If not and anyone gets Legionnaire's disease, you're potentially liable.