Heat only boiler unvented cylinder, which new boiler?

[melliottuk]

I currently have a heat only boiler connected to a gledhill unvented cylinder. It is currently set up with external expansion vessel on the cylinder (white), various valves, external pump and a small header tank which I think is known as a open vented primary system, this keeps the heating and tank coil loop topped up.

This heat only boiler is now dead, my understanding is that I have a few options:

1. Replace the heat only boiler with another heat only boiler (keeping valves, pump, header)
2. Replace the heat only boiler with a system boiler, I think this means that the pump and small header tank can be removed and the boiler itself will provide a sealed primary system. This sounds good but will require my current system to be slightly reconfigured. The benefits being that the bits removed are old and might need replacing soon anyway.
3. Replace the lot with a good combi, the house is 4 bed 2 bathroom, with unvented cylinder feeding two showers (2 adults, 2 kids).

Any ideas on what to do, it feels like a have a good system but it's old and the world seems to have moved onto system boilers. I think the setup I have must be a very early unvented system.

It may be also important to note the location of all this stuff:
Boiler is in the garage
Unvented cylinder and header is in the loft
Pump is in the airing cupboard, in the location where the original hot water tank would have been when the house was built.

Thanks,

 

[muggles]

System boilers tend to have better modulation so are more efficient more of the time. They also tend to have stainless heat exchangers rather than aluminium ones, and as you say everything is in the box and covered by a long warranty. If you've got an unvented cylinder that's not taking up room I'd be inclined to keep it. Get a boiler that can do hot water priority for best results

 

[fixitflav]

This heat only boiler is now dead, my understanding is that I have a few options:

Another option is to bring the current one back to life. What makes you think it can't be fixed?

 

[melliottuk]

Thanks, I'm hoping that the old one can be fixed, I'm half expecting it to be beyond repair as it's 19 years old, a Baxi Suprima 80 HE.

 

[MNW67]

Any ideas on what to do, it feels like a have a good system

This is just a personal opinion. But I think that unless you are actually interested in boilers and setting them up, then you are not going to notice much difference either way. A system boiler might be slightly more efficient. A stainless steel heat exchanger might also be slightly more efficient, but that is disputed.

I believe the main developments over the past twenty years have been things like priority hot water, weather compensation and load compensation. These are all ways of trying to make the boiler a bit more efficient and also making the heating feel more comfortable, by having a flow temperature which varies automatically. I believe these things are sometimes easier with a system boiler. Worcester Bosch, for instance, don't let you do them on their heat only boilers. But every manufacturer is different. With some you need to use their own expensive controls. Others have the functions built in and you can use cheaper third party controls. People on here should be able to advise if you are interested.

Then there are developments in controlling the system. For instance setting the heating from your phone and having thermostat radiator valves which can be altered remotely.