Ecodan Cylinder Possible Weeping Around Thermostat Port - Domestic Hot Water & Cylinders

RE: Ecodan Cylinder Possible Weeping Around Thermostat Port

Gruff2001 — Thu, 12 Mar 2026 12:59:30 +0000

Update:

Mitsubishi sent an engineer around. It was limescale from seepage. Removed plug, cleaned etc, etc

Root cause most likely under-pressured DHW expansion vessel (system serviced 6mths ago). Fingers crossed it’s now sorted

RE: Ecodan Cylinder Possible Weeping Around Thermostat Port

ASHP-BOBBA — Wed, 25 Feb 2026 23:09:41 +0000

This is likely thread sealant for the pocket plug, very easy fix if it starts oozing out, unless you get an actual leak it is probably fine, what you could do is ask the installer to remove the white trim cover cap and just make sure the joint is not leaking into the insulation.

Ecodan Cylinder Possible Weeping Around Thermostat Port

Gruff2001 — Tue, 24 Feb 2026 17:10:29 +0000

2.5 years of use and I’ve just spotted a white residue around the thermostat port, wasn’t there a month ago

I’ve contacted the installer, a fitter got back to me and said there’s nothing to worry about it’s just a glue residue that sometimes develops. To confuse things, a higher up in the firm emailed me saying it isn’t right and that I should contact Mitsubishi.

Clearly this isn’t helpful and I will be contacting them again when business is open. Before then I’d like to be as informed as possible. Could anyone shed some light on this? Thanks in anticipation

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