Upgrading from my Baxi Bermuda back boiler (!)

[v8pete]

Well, after 20 years of faithful service it's time to kick out our old Baxi Bermuda back boiler (!!) and donate it to the local museum! It was already probably 10 years old when we bought the house, but has only ever had one minor fault since we've been here. With gas prices rising, I'm looking at getting rid early next year and getting something a bit more modern. To that end, I'd be grateful for some advice if you think I'm on the right lines here ...

I don't want to rip out all the existing rads and plumbing as most of them I replaced only 3 years ago. The plumbing is the original installation, still in good order, but is a slightly odd setup in that it uses fairly large diameter copper for the main runs but has 8mm OD microbore tails to most of the rads. This doesn't overly bother me as the flow rate that we get with the current system seems fine. I'm keen to retain a hot water cylinder, as this allows us to keep the airing cupboard, and have an immersion heater as backup. Don't mind at all keeping header tanks in the loft space either..One thing also to note with our current system is that it does seem to let a bit of air into the rads now and again, which I'm thinking would be a major problem if I should try and convert to a sealed system combi boiler.

So, after a bit of Googling around, I think that my best bet, is to go for an open-vented condensing boiler, and it appears that something like the Viessmann Vitodens 100-W open vented would probably fit the bill best? From what I read, these have a good design of heat exchanger that's generally less prone to blocking when used with old plumbing/rads than some of the other makes. I've also heard that it's essential to fit a good filter too when reusing the old plumbing.


I'd be grateful for any advice and general comment on my plan and possible pitfalls and gotchas or any other stupid stuff I've blissfully overlooked! Many thanks for any input, Pete.

 

[wattsie1987]

I personnaly only fit w\b or vaillant so can't comment on the above boiler. Deff a decent filter and a good chemical clean as a minimum. Possible gas re run required. Ideally o/s wall for boiler will keep costs down and should be OK for condense route. Trv's required on rads and I'd fit a new pump and motorised valve/s. I'd get the feed and vent checked out too sounds like its sucking in air.

 

[kris]

A sealed system or combi is easier and cheaper to instal because you dont have to run vent pipes and cylinder coil pipes , the heating pipes would need to be run to boilers new position but depending on where the new one would be sited would depend best road to go,
Me i prefer pressurissed every time , boiler and cylinder however a standard system boiler re situated then tie into existing cylinder and do away with little tank in attic , or if you wanted a combi that would be just as feesible,
Best to get an engineer round to tell you of your options ,,

 

[kris]

Forgot to say welcome to the forum pete,

 

[townfanjon]

Go for the Viessmann , great boilers .

 

[townfanjon]

Pete, mega long shot, are you a member of the cobra forum, we have a v8pete on there.

 

[wattsie1987]

I prefer sealed too had some bad experiences with pressurised microbore tho. A decent combi in the airing cupboard and a small rad so you can still air clothes would be my preference.

 

[Ermintrude]

They are not good boilers. Also with open vent on microbore your going to be flushing every 5 years minimum. I wouldn't hesitate to fit a sealed system. We do a few a week. Micro Bore on open vent will over-pump and just suck in oxygen.

DO NOT FIT OPEN VENT COMBI.

Also fit one with a plate hex ans they are a lot easier and cheaper to swap when the boiler scales up.

 

[Reg Man]

What ever boiler you install, make it a sealed system, rip out the 8mm pipe and replace with 15mm. Power flush the system and add protection fluid. Upgrade the controls to meet current part L Building Regulations. Worth doing it properly whilst you are investing in a new boiler.

 

[v8pete]

Hi everyone,

Firstly very many thanks for all the great inputs! So, having read everyone's replies I'm trying to figure out what would be the best route for me to take. I really, really want to avoid ripping out the short runs of 8mm Microbore on most of the rads., as they've been fine to date, and this will entail a hell of a lot more work taking up floorboards and carpets in most rooms in the house.
As the cold water tank and heating header tank are in good condition and already there, surely it would be ok just to leave this setup as is, and just modify as necessary, assuming I clean it all out properly?
I'm not really trying to squeeze the last bit of efficiency out of my setup, but I do want to make sure that its totally reliable, so the open vented system seems like the least amount of upheaval and should be an improvement on the Baxi Bermuda, I hope! I thought that going the open vented route and opting for a boiler with a good type of heat exchanger design (allegedly the Veissmann is less prone to clogging and is made from stainless?) is my best bet for a reliable system?
I'm not at all trying to challenge the views of the professionals here, but for a novice like me it's difficult to understand why there are quite a few people advising not to fit an open vented boiler?

Cheers again, and many thanks for everyone's input and help!

 

[Mike Jackson]

Look at Intergas boilers. You could ride a bike through the heat exchanger on them.

 

[tamz]

^^^True ^^^

The copper you see are the waterways. Open or sealed, its the same boiler.

A properly designed open vent system won't give you any bother with drawing air or pumping over but a sealed system guarantees a numpty can fit it :wink:

 

[lame plumber]

Numpties rule

 

[Reg Man]

^^^True ^^^
View attachment 20143
The copper you see are the waterways. Open or sealed, its the same boiler.

A properly designed open vent system won't give you any bother with drawing air or pumping over but a sealed system guarantees a numpty can fit it :wink:

But the benefit to a sealed system Is, it is not open to atmosphere and contamination and degradation of water quality is minimalized.

 

[jtsplumbing]

Depending on what space you have to fit a new boiler , have you considered the New Baxi Back boiler unit (Condensing) only thing is it comes with an electric fire front.

 

[dopey]

Baxi duotec every time

 

[gbheatingtech]

Get a 3 local heating enginners to come by and measure up for doing the job. Have a chat with them and see what they recommend, as they are the pros! have a caht with them as well and see which ones know their onions and which ones just want to 'fit' boilers and be home by 5.

A few jobs Ive done similar to this will take a good 3 days with all the commissioning and flushing, also if you want to keep the o/v set up maybe get a price for changing cylinder as well, did one earlier in the year where cylinder coil had perished over time so un expected cost to customer wasnt very nice.

 

[v8pete]

Many thanks guys for all the great advice! Always helps to be well informed before making too many firm plans and setting about buying stuff. I'll pop back and update this thread when things have moved on a bit further

 

[townfanjon]

Pete, it's like this pal, we put rv8's, cleveland's,350 etc etc. in our cobras, they are all tried and tested good engines, nothing wrong with them . But an LS3 would be the ultimate and modem day engine. That's good analogy on a sealed or open vented heating system.

speak soon.