Help - Boiler not working properly

[STEVEROG]

My recently fitted Gloworm 24hxi boiler does not seem to work properly when both my heating and hot water are switched ON. Below a summary;-

1. Hot water ONLY switched on: Boiler runs for about 30 mins to heat water to required temperature then boiler cuts in/out to maintain temperature as expected. Water is nice and hot

2. Heating ONLY. As above, rads get nice and hot, boiler cuts in/out to maintain temperature as expected.

3. Both heating and Hot water switched on. Radiators only get warm (not hot) and boiler never cuts out, only drops to one burner running and no less.

What's going on?

Steve

 

[gas4you]

Was the system flushed and cleaned properly?

Have you got 2 x 2 port valves or a 3 port?

Were these new with the boiler, or are they existing?

 

[STEVEROG]

System was only bled down and run-through with a hose, not power cleaned.

Not sure about valves, where would these be and how would I know the difference?

The only thing that was changed was the boiler and I think a new water pump, that's it.

Note that the installation is in my mums property not mine (posting on her behalf).

I did wonder if the problem was the actual boiler being too small for the property as we are talking about a 9 bedroom guest house spread over three floors?

Steve

 

[glasgowgas]

what is the KiloWatt rating of the hot water cylinder??

 

[bengasman]

Could be that the combined load of ch and dhw water is way above the power of the boiler.
In itself there is nothing to worry about if ch and dhw work fine independently.
In fact this would be the theoretically ideal situation; when half possible, I install timers that are fully independent for the sole purpose of never having the ch and dhw on at the same time.