Hot water only high pressure

MSaxp

Hi,

In our new house, we have the following issue:

We only get hot water when the hot water tap is at full (or almost full) flow. If we only open it half way, the water gets cold again. Which is annoying, as in the kitchen , it tends to splash everywhere when its at full whack.

(system is an unvented system, boiler downstairs, hot water cylinder upstairs)

any help appreciated

Crinkmeister

Sorry - I'm confused! You have an unvented hot water cylinder which provides your hot water - which will be hot whatever the tap setting is. I could understand your problem if you had a combi system.

Avoriaz

Do you have separate hot and cold taps or is it a mixer tap?

If the former I can't understand the problem. If the latter, maybe the mixer tap is faulty.

One possibility, although unlikely, is incorrect plumbing and your hot tap is also wrongly connected to a cold supply with partial flow. When the hot is on full flow you don't notice the small amount of cold water but you do when the hot isn't on full flow.

However that would require a spectacularly bad bit of plumbing. Is it a new build on a large development?

MSaxp

I know it doesn't make much sense but it is true. Sounds like a prank though

Happens to both separate and mixer taps.

Hot water tap: I turn it on at high flow, it gets perfectly warm. I turn it down , so that you can wash your hands without splashing everywhere and it gets cold again.

Its a 7 year old house. Yes, relatively large development, built by one of the big developers. Hot water cylinder is a Range tribune HE

MSaxp

Still no progress with this one. The hot water tank company were also puzzled about it. They suggested some crossflow between the hot and cold water pipes.

We noticed yesterday that while i was having a shower, the problem didnt exist for the rest of the house taps. Pretty much that if more hot water taps are used, the water remains hot even at low flows. Which suggest some sort of a system pressure issue?

Crinkmeister

I wonder if your shower mixer is plumbed in correctly or is faulty in some way?