Why is my water pressure low for hot water in shower?

MarkK1986 · 21-07-2022 02:18PM #1

Hi,

I have a non electric shower and the pressure is fine when running cold water. As soon as I change it to hot the pressure dramatically reduces and actually cuts out on and off while remaining weak.

Any ideas on why this is?

Thanks

John.G · 22-07-2022 06:54AM

Is the cold supply from the mains or from a tank in the attic? And is the hot supply from a vented (gravity) or unvented HW Cylinder?

MarkK1986 · 22-07-2022 07:37AM

https://www.boards.ie/discussion/comment/119370853#Comment_119370853

Cold is from a tank and it is a unvented hw cylinder

John.G · 22-07-2022 12:53PM

What is supplying the unvented HW cylinder?, is it from the mains or is it pumped?, any idea of its pressure? Normally, a unvented HW cylinder would be fed either from the mains or a pumped supply with the cold water taken off a balanced supply from the combination valve on the cold water supply to the cylinder, it is very unusual to have it as you have it, ie gravity cold as the shower shuttle valve has to greatly throttle in the hot side to enable the very low pressure cold water to mix. Is it a thermostatically controlled shower?.

Why is my water pressure low for hot water in shower?

Answers