Heating System Upgrade

[HavagoHarry]

I need to get our heating upgraded. It currently consists of two entirely separate open vent systems in the same property running off a Danesmoor 15/19 and a Trianco 15/19. Both are a bit ancient and the Danesmoor has been playing up for a while now. We use quite a bit of oil as you might expect. So I want to get both replaced with a single boiler (sized at 30Kw) and ideally join the two sides together.

My plan is to do it in stages:

1. Replace the utility Trianco with an external 30Kw. I want to go to a sealed system but would ideally do this after getting the external installed and working.

2. Next, remove the Danesmoor and join the two systems together.
3. Then convert the Danesmoor side to sealed.
4. Last, go to sealed for the domestic how water by removing the tanks and going to a single appropriate spec tank. I would do the rest myself but get someone in for this bit.

Also, I would of course look to get the new boiler commissioned by a specialist.

So I want to know:
Does this all sound reasonable?
Can I use a sealed system boiler on an open vent system for a while if I need to?
The potential for leaks is a concern with the pipe work being quite old. Should I let this put me off going for sealed?
Should I be concerned about going sealed with the existing hot water tanks albeit temporarily?
All other thoughts/comments and criticisms gratefully received.
Thanks...

 

[xr4x4]

Maybe wrong, but don't think I am... You won't be able to run two systems connected together on vented and sealed.

The sealed system will just fill the open tank up from the bottom until it overflows

 

[HavagoHarry]

Hi xr4x4, thanks for pointing that one out. I realise now the order is not quite right. I would, of course, have to convert the second side to sealed before joining them.

Was looking at the Grant website last night. Their external boiler can be fitted with a kit so I could buy the vented version and then convert the boiler itself later along with the pipework.
Cheers.