Radiator scorching, no hot water

[GaryMul]

Hi all, I have a Baxi Combi boiler, 10 years old. Recently, when I turn heat on, radiators heat up fine. However if I turn hot water on, I get no hot water, but the radiators go roasting hot, even if the heat is turned off. I have bled all the radiators. I suspect it might be something to do with my pump connected to boiler in airing cupboard. Usually pipes get hot when hot water is on. This no longer happens. I think it may be a pressure problem, but my pump does not display pressure so I have no way of changing/fixing this. FYI I have a grundfos UPS 15-50 pump. I need some ideas please. Thanks everyone.

 

[ChrisR]

First we need to know if you have a Combi or not. If sso the pump will be inside it.
Please check boiler make and model, and do you have pump and motorised valves somewhere else, with a hot water tank....?

 

[GaryMul]

yes, i have a baxi solo 2 boiler, that heats water and radiators. also a grundfos ups 15-50 pump at my water tank. left heat on all night last night, worked fine, no noise, tried to switch hot water on, (while leaving heat on this morning) same problem happened ie radiators went hot, water did not heat

 

[kevplumb]

methinks

lack of water

FWIW

 

[GaryMul]

so how do i fix it?