Needing a new boiler

iknownothing30 · 2 Jan 2026 at 10:33

Hi I wonder if anybody can help. We have underfloor heating around 1400 ft.² and 12 radiators on top two floors which we could really do with more because some of the rooms are very big and only have one radiator and also there are no radiators on any of the Floor hallways up there. We have an ideal VogueS32 GEN two and it has always struggled with heating the underfloor heating if we have all of the areas on. It’s now six years old and we are having problems with our motorised zones so the underfloor heating sometimes doesn’t come on or it seems to go off when the heating upstairs comes on and sometimes the heating on the middle floor doesn’t come on so those motorised valves need replacing however I was thinking that we might get a new boiler that is maybe a little bit more powerful to deal with our underfloor heating and also we’d like to have some sort of hive set up as well which the plumber and electrician at the time said we weren’t able to have with this boiler. Could anybody recommend a new boiler that would be able to deal with such a big area? It’s a six bedroom house over three floors with three bathrooms. With 12 radiators but really it needs at least six more radiators and two bigger ones putting in our bedroom because they are tiny thanks for any help or guidance.
Vic

henry hoov3r · 2 Jan 2026 at 10:50

Have the radiators/underfloor heating system been balanced?

iknownothing30 · 2 Jan 2026 at 11:43

I don’t know? I know that the heating goes up stairs to the radiators and ten comes back down to ufh. Because a heating engineer came out and told me once but he never came back and then we just lived with it. But now the motorised zone valves need replacing. I’m just wondering what else needs doing.

jaybee · 2 Jan 2026 at 11:59

At that size and complexity it sounds like you need a heating engineer to come and do an assessment as to what you might need. There are some things you can try to do yourself if you like.

1. Fix all the motorised valves as they are clearly an issue. No point troubleshooting when there are issues in plain sight that need fixing.

2. Go round and bleed all the radiators starting on first floor finishing on top.

3. Ensure boiler has correct pressure on the dial or anywhere else you have a pressure gauge like airing cupboard near cylinder. Run the heating for a while and observe whether things are warmer. Check all the rads are warm not just at the top, but at the bottom as well. They will be less hot at the bottom but they should not have noticeably obvious cold differential at the bottom. If it does have cold spots like this at bottom, they could be full of sludge and sediment build up. In which case...

4. Take off bad radiators and blast them out with hose, then top up your system with inhibitor at a high point. If you have a towel rail on top floor this is ideal. Retest.

5. Also check any pumps you have in the system are set to full speed, especially one for underfloor.

radderfire · Monday at 23:11

First, work out what size of system your current boiler is designed for.

b0rn2sk8 · Monday at 23:41

The issue is not with the boiler or it not being powerful enough.

It’s 32kw which is absolutely massive for a ‘normal’ house. To put this into perspective, my house is slightly larger and it is heated more than adequately with a heat pump which as a maximum output of 6kw.

Combi boilers are sized for hot water, that’s why they are so large. Heating cold water from 10C to 50C at 15L/min takes a lot of power. Heating spaces, not so much.

As I said at the top of the post, your boiler is fine, the issue will be with everything which is connected to the boiler, how it’s been designed and the controls. It may be a basic balancing issue but the chances are the controls are poorly set up also.

You need to get someone in to correctly configure and balance the system if you can’t do this yourself. Balancing is an easy thing you can do yourself, YouTube is your friend here.

SpeedFreak · Tuesday at 06:37

I would say that the boiler size with poor modulation isn't great (only 7:1) but should in no way struggle to heat the house. Best and most modern approach would be to reduce the number of zones as the house is a good size but not ridiculous, ultimately the heat will flow upwards. Your base load should be via the U/F zone which should tick over at 23-24 degrees. I personally would have the middle and top floor on one zone and just balance the radiators accordingly. Get a competent heating engineer to inspect the system, check the manifolds for faults. I know it is a combi, but do you have a hot water tank?