Combi Boiler Help

AbbyCarr98

We recently purchased our first house and it has a Combi Boiler. We've both never had our own house, or rented and only ever had knowledge of conventional boilers. Shower works perfectly, takes a minute or so to run hot and then runs continually hot and is suitably hot! All of our other taps in the bathroom and kitchen run boiling hot too. However we've come into issues with our bath. After a minute it runs burning hot, then another minute and it will run clap cold and stay cold. It's a bit confusing as we can have nice long hot showers without any problems at all. It is a Gloworm Combi Boiler and has a pre heat facility although I don't know if this makes a difference. It's been 2 months and I'd just love a full hot bath! Any ideas? I don't think there's any faults with the boiler as it was recently serviced and all fine, and no other issues.

Browntoa

Bath tap is greater flow so may be taking more water than can be heated properly.

Have you tried running it on a much lower flow ?

AbbyCarr98

The shower is particularly powerful with a very large surface area which we have no issues with. The water runs out of the bath taps burning hot but then goes clap cold and never goes hot again regardless of changing the flow. But it does get initially hot on the fastest flow. The bathroom was fitted in not too long prior to moving in, perhaps 6 months.

Slithery

Are you sure that the combi is your only heating system?

Is it possible that there is a small immersion tank somewhere feeding the bath?

karatepet

Does the boiler allow you to control the water and heating seperate?
If i have the water on the heating is turned off until the water is turned off.

AbbyCarr98

I'm certain there isn't anything else. The boiler is in its own cupboard, and there's nothing else in there or in the loft. I don't know who we'd need to call out to look into the situation as it seems the boiler works fine, as our showers are lovely and powerful and hot. It's just strange the bath runs burning hot and then instantly cold, the bathroom taps and kitchen taps and shower don't do this.

AbbyCarr98

I'm not sure if if is separate. We have a thermostat for the heating we can manually change, there is nothing for the water as it is heated on demand. The boiler was serviced in October and no fault or work required.

karatepet

do you know the model number,so you can check online for the manual?

AbbyCarr98

I have the manual for it. But everything else works as normal. It's a GloWorm 30cxi Combi Boiler.

karatepet

looking at the manual,could be the 3 way valve not working properly.

AbbyCarr98

Could you explain what that does and why it could be causing the issue?