Central heating: sealed system vs open vented

[RockaLock]

Our boiler broke down on 23 Dec (no central heating or hot water since then, which has been fun...)

We are due to have a new boiler fitted this week - hurrah!

The plumber is recommending that at the same time, he switches our system from an open vented system to a sealed system. This should prevent sludge etc building up, which is what has killed the boiler this time around.

All sounds good. BUT I understand that this comes with the risk of leaks from our pipework, as a sealed system is under higher pressure. A lot of our pipe work is very hidden away and it would be an absolute nightmare and ££££ to resolve if this happened.

Does anyone have any experience, good or bad, from changing to a sealed system?

We changed. Ended up having to take up carpets and replace lots of microbore pipes and 3 radiators. That was all fine as we are renovating house this year anyway - and it's lovely having radiators that now work.

No leaks though.

If you currently have an open vented, do you not have a hot water tank in the airing cupboard with an electric immersion heater on it?
I'd keep it open vented but opinions differ.

Thanks, Blackdog. I'm glad it worked out for you!

We have a megaflo hot water tank, and as far as I know it hasn't got an immersion heater on it (it's in the loft, so I've never really had a good look at it). If I find out on Thursday that it does, and that we could have been washing properly for the last 2 weeks, I shall be seriously unamused!

We are definitely leaning towards leaving it open vented, though.

I've got sealed as it's more efficient but is dependent on use of course

I changed from open to sealed as the sludge killed the boiler and it’s much better

Our boiler also broke down on 23rd December! It is open vented. We have a hot water tank (inherited when we bought the house) and an immersion but it transpired it had never been wired up. So, over Christmas we shivered and washed in cold water.

We managed to get an electrician to wire it in on the 28th so we have at least had hot water since then. I asked the heating engineer whether we should take the opportunity to move over to a sealed combi boiler (I have only ever had this type before in other houses) and he said he has actively chosen a hot water tank system for the house he has just renovated as it does mean you don't lose hot water if the boiler breaks down.

So we are staying with the system we've got as up until 2 days before Christmas it had never given us any problems, whereas I've had many a problem with leaks and loss of water pressure in various combi boilers I've owned.

I hope you get sorted soon OP. Why do these things happen at the worst possible time?!

Prawn, I'm glad you got hot water fixed up quickly! We're mostly warm, thanks to lots of plug in radiators (not looking forward to the electricity bill, though...) but the lack of hot water has been hideous.

I hope you get your heating back on soon!

Eloise, when you changed, did you have any problems with pipe work springing leaks? Is your house relatively new? Ours is a mixture of 1930s + newish and so the risk of a joint giving way under the higher pressure is worrying me,

Our house is 1980 and we have had no probs but will need to change the boiler soon as it’s now running badly as it is damaged from the sludge - we will change to a heat pump

Hi OP.
Do you know this plumber?

Sounds like they’re angling for ££ by switching the system to closed.

Why not have a magnetic filter installed on the system you have now to catch the sludge.

www.screwfix.com/p/ideal-heating-system-filter-22mm/5931x

An example of a filter.
If you have a megaflo cylinder I’d have thought you already had one installed

We do know the plumber, he's ok. He's happy to leave the system as it is, if that's what we want - he won't push us in to changing it.

I'm fairly sure we do have a magnetic filter near the hot water tank already. Possibly it hasn't been emptied out for a while though, so whether that's an issue, I don't know.

I had a filter too, only worked to a certain extent