Hot water isn't (very) hot :(

UserX

I have a Worcester Combi boiler of indeterminate age. We've never found the water to run particularly hot but it hadn't necessarily been a problem given that we have a dishwasher and electric showers! However my youngest does like to have a bath from time to time.

Because it takes a while for the hot water to run through to the taps, when I run a bath for her I draw off the cold water into a bucket (to use the flush the loo!) and then run just hot water form the tap. It's never run hot enough to need cold adding

I've just run her a bath for the first time in a few weeks and by the time I'd finished it was decidedly lukewarm. So I ran the hot water at the hand basin.

- The boiler is firing and running consistently
- However the water temp dips quite markedly up & down and at its most lukewarm, is definitely not hot enough to contribute to a nice bath

Edit to add - and I don't know if it makes a difference but I turned the heating off yesterday so the only time the boiler will be firing now will be when I need hot water.

Any suggestions?

lee111s

Have you not got a water tenp dial on your boiler? Mine has, had to turn it right down as I had the opposite issue, scalding water!

moneyistooshorttomention

My thoughts too, re changing temperature set on boiler.

I've found workmen were going to leave my hotwater at a temperature that equalled "warm" and had to get them to adjust that to ensure my hot water is actually hot.

Takes a while for it to warm up a bit and a wasted washing-up bowl or two of water whilst I'm waiting, but then it runs hot.

Lgas

My bet would be blocked plate heat exchanger, if the temperature is fluctuating, the boiler is still firing, and the water isn't getting very hot.

Also whilst you're running the tap have a feel of the bigger pipes going from the boiler (the flow if you know which that is, should say on the sticker underneath), as that will eliminate the diverter valve being the problem. In that instance the heat could be going around the heating pipes instead.

Lgas

On those boilers sometimes the temperature knobs snap inside so turning them does nothing - just another thought. You can pull them off to check (they should have a long spindle).

UserX

Thanks all.

The temp dial is set on max. I've been reading around and I do get a better temp if I don't turn the taps on full (but we have quite a big bath, so that will get tedious!) However it does still fluctuate even at slower speed.

Lgas

Yep still sounds like the plate heat exchanger. Combi's are designed to reach a set temperature rise at a certain flow rate. Particularly if there is a restriction in the plate heat exchanger then the faster you run the tap the less heat transfer will take place (to the water). So by running it very slowly it takes longer to pass through the heat exchanger and warms up a bit better. I'd get a Gas Safe registered gas engineer in.

neneromanova

have you tried opening the taps just a little, and not fully? we used to have this problem, then I ran the water slowly and it seemed to become hotter