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Domestic Hot Water and HIU issues
Gaurav 19/01/2026 - 8.16 AM
I have an issue with my hot water supply, likely arising from the HIU. I usually have some hot water flowing when I open the tap but it goes cold in about a minute. I then have to wait another couple of mins before getting it hot again. I also have under floor heating and that seems to be working fine. I suspect there may be an issue with the flow sensor/switch or the temperature sensor on the DHW supply but might need help to investigate and fix. Would anyone know what might be happening here?
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2 Answers
HUN-POWER ELECTRICAL
Rating: 4.9 out of 5
Find the plumber they need to visit to you to investigate your u.f.h.
Answered19 January 2026
0
Anonymous user
The fact that hot water returns again after a short wait suggests the HIU is resetting rather than there being a supply issue. It would need on-site checks of flow rates, sensors, strainers, and fault codes (if applicable) to confirm and repair.
First check I would recommend is a faulty or sticking DHW flow sensor/switch, which can drop the HIU out after initial demand
Answered19 January 2026
0