Smelly hot water out of upstairs bathroom tap only

[Mw Roofline]

Downstairs taps are fine, just the upstairs hot water tap pongs a bit.

I thought maybe some kind of nesting animal had got into the cold water tank in the loft but then I realised we had a new baxi condensing boiler fitted about 4 years ago and iirc the tank(s) in the loft are no longer used?

Any advice much appreciated

 

[JohnD]

some new boilers are combis (no tank or cylinder) and some aren't. Mine isn't. Is yours?

best have a look in the loft.

if you have recently had plumbing work done it might be some material used by the plumber on jointing or soldering the pipes.

 

[Mw Roofline]

some new boilers are combis (no tank or cylinder) and some aren't. Mine isn't. Is yours?

Nope, nothing up there at all

Its been years since any work done on the ch system.

weird!