Bath hot tap doesn't get as hot as other taps

Participant · 24 Mar 2013 at 12:18

Hi all

Grateful if you could help me troubleshoot this weird problem I've got please.

Basically, the hot tap for the bath in the main family bathroom only ever gets moderately warm. No other tap in the house has this problem, so I'm fairly sure it's not a boiler problem. The boiler works fine otherwise. The sink in the bathroom gets hot no problem.

It seems to be pointing to a faulty tap mixer, but I don't want to replace it before I'm sure that's the thing. Must be that though, right?

Ps the hot water comes directly from the boiler ie there's no hot water tank.

Participant · 24 Mar 2013 at 14:46

Thanks guys.

The problem's been there ever since we moved into the house in December. It's hot enough (just) for a bath for the little one, so it's been low down my list of priorities. Looking at getting it sorted now though.

I'll have a look at it and if there's no adjustment or obvious resolution, I'll just replace it with one fro Screwfix.

Participant · 24 Mar 2013 at 16:16

Just been up to have a look. I don't think there is a thermostatic adjustment:

However I did discover something...when I turn the cold tap very tightly off with all my strength, the hot tap runs very hot as it should. Therefore I'm guessing that I actually have a cold tap problem.

Is this likely to be serviceable, and if so, how? Annoyingly they don't seem to have put isolation taps / valves on the pipes.

Thanks a lot for the help so far!

Participant · 24 Mar 2013 at 17:11

Cheers guys. We're just going to replace it as we fancy a shower mixer on the tap too.

At least we know it's not faulty pipework or a problem with the boiler!

Participant · 24 Mar 2013 at 17:25

I've found the problem and posted it already

. The boiler is fine, the kitchen tap chucks out hot water at a hell of a lick. It was the fact that the mixer was drawing in cold water even when closed.

Participant · 24 Mar 2013 at 20:49

Sounds like a good idea. Going to go to Screwfix tomorrow and pick one up.

Participant · 25 Mar 2013 at 23:15

Well I fitted the replacement tap, and I think I need to go cap in hand to orionaut, because I in fact still have the problem that the hot water tap in the bath doesn't produce really hot water until I dial back the flow slightly on the hot tap.

It's the only tap that's served by 22mm pipe in the house as far as I can see, so I think the extra flow is just too much for the boiler, which is a cheapy Ravenheat csi120. So unless there's an actual fault with the boiler, we're just going to put up with it until we can justify a replacement boiler or an unvented cylinder. It still chucks out hot water at a decent lick and the shower off the mixer tap is a million times better than the crappy electric on the wall, so maybe in a few years we'll look at a 50kW Worcester Bosch or something.

I've read about water / water heat exchangers getting gammed up, but tbh with this cold weather, I reckon my boiler just isn't man enough to provide a high enough rise at full flow.