Water Not Hot Into Bath

[jmck66]

We've got a combi condenser boiler. When hot water is run into the bath it doesn't run hot enough - only luke warm. When the hot tap in the basin is turned on straight afterwards, the water is boiling straight away into the basin as if all the hot water has gone to the basin tap instead of the bath. Asked a boiler engineer because it was suggested it was the diverter valve; engineer said it wouldn't be because not all hot taps were affected and it would be a problem with the taps. Disconnected water supply from bath taps and ran hot - it was exactly the same through the pipe. I've had this problem for about three years now and no one seems to be able to come up with a solution! Good job we've got a shower!! Any suggestions - please??

[-Talbot-]

Does it run hot if you run the tap slower?

[jmck66]

Tried running it slower but it doesn't stay hot if it starts getting warmer and if it's too slow it's not enough for the boiler to fire up.

[-Talbot-]

If your basin tap gets hot your bath tap should too.
Try letting the boiler kick in then slow the tap down.

[jmck66]

Tried that -Talbot-! It's so frustrating because it used to be fine. Basin tap runs normally when just using that - runs cold at first and gradually heats up as it should but if the bath tap has been run, it's as if all the hot water has backed up in the basin hot tap and it runs really hot straight away.

[-Talbot-]

Is the bath tap a mixer?

[jmck66]

Yes, but we've ran the water with the pipe disconnected from the tap and it was the same! You've got your work cut out with this one haven't you - sorry!

[Bathsheba]

This is an accurate description of my own situation!!

x x

[-Talbot-]

Difficult from a keyboard lol.

If the pipe is 22mm then it could be coming out too fast and the tap may be faulty. You could try running it through the pipe at a slower rate to test it.

[retrocop]

Earlier this year we had a similar problem though we do not have a combi boiler.The mixer bath taps would not run hot water through the shower attachment although all other hot taps were OK in the house. I changed the mixer for a new one and all ok. I took the old mixer apart and found no problems with the innards. I can only think that limescale had built up with in the channels of the main body and blocked the hot water supply.

[jmck66]

I'll give that a try Talbot, but not tonight! I'll get back to you tomorrow to let you know the hot water is back !??????

[The Builder]

This often happens if the hot supply to the bath mixer is laid out badly. A tortuous route that slows the flow. The basin sounds as though it has a more direct run from the boiler.

Has there been work done in the past? Perhaps converting from a gravity system to the combi you have now.

[whiskeryron]

As an experiment what would happen if you disconnected hot feed from the wash basin & connected to the hot tap of the bath ?