Changing from oil to gas - which combi boiler / microbore pipes

jenny-wren

We're changing our heating system from oil to gas and will be installing a Worcester Bosch combi boiler in the kitchen. We'll take away a kitchen cupboard to get the boiler installed but, in a couple of years time, we want to get a new kitchen and have the boiler housed within a cupboard.

It's a 3 bedroom house with 1 bathroom and 8 radiators. The boilers we are considering are the 30i, 30Si Compact and the 32CDi Compact.

There seems to be quite a difference in the quotes we have received between the different models although the boiler outputs are very similar. We want to make sure the system will be adequate for the lifespan of the boiler but obviously we don't want to have to pay more than we need to.

We have microbore piping running to the majority of the radiators from the central heating manifold. A couple of installers have strongly recommended that we replace the microbore pipes (at an additional cost of up to £1200!). Others haven't mentioned the pipes. One installer would replace pipes under the floorboards, another would run the pipes down the walls and box them in. We will be replacing the radiators as part of the installation. It's a 1950s house with no hard water issues.

Would the 30i be much more difficult to house in a kitchen cupboard as it is bigger than the other two?

Is it worth the extra expense to get either the 30si or the 32CDi?

Do we really need to replace the microbore piping?

Any opinions welcomed.

jenny-wren

Anyone got any suggestions? We need to make a decision as soon as possible. Thanks.

moneyistooshorttomention

Well - avoid the one that wants to run the pipes down the walls obviously.

Pipes are supposed to be under floorboards - and that's where most people expect them to be (ie out of sight).

With having concrete floors and concrete block walls in this house - I've had quite a job of it getting radiator pipes hidden as far as possible (eg by re-routing them inside cupboards). I've got one and a bit pipes that couldn't be hidden in the event (the "bit" being where I got the pipe going down wall moved to side of window - so I could at least hide all except the top 1' or so of it - by having floorlength curtains). Then there is one completely on show - and I really don't like the look of it.

When boxing-in pipes that shouldnt be on show - I found that the one beside the window had basically had the pipes bent a little out of true and the wrong size "box" put on top of it to hide the pipes as best possible. That resulted in the pipes "knocking" against the cover and making a noise and that cover had to be replaced. You would need a high-quality workman to ensure the job was done properly enough to avoid that.

By "microbore" pipes - I guess you mean the ones this house came with - ie ones that are very narrow in width. I wasn't pleased to find that's what the house had - but have left them at that size and the new bits of piping have had to be done in same narrow width. I don't think I've had any problems with them being too narrow - though I must say I'd only ever put in normal width pipes if I were starting from scratch:cool:. If money had been no object - then I would have had them all ripped out and totally new (normal width) pipes put in. But then, if money was no object, I would have bought a rather better house than this in the first place...

southcoastrgi

A lot of installers don't like microbore as it's difficult to flush & it's easy to damage/crease etc, if it's been working fine with your oil boiler then there is no reason it won't work with the new gas one, I'm not gonna comment on your choice of boiler because I don't like or fit Worcester

moneyistooshorttomention

Correct that microbore pipes are easy to "damage/crease". I've found that:(.

I was told they would be harder to "flush" if need be. Obviously - I'm crossing my fingers they won't ever need flushing. If they do - then I'll presumably find out at that point whether it is indeed harder to do.

Of course - part of the reason for sticking to these narrow pipes in the case of my particular house is precisely because I'm having problems hiding them anyway (that darn concrete floor) and thought it would be easier to hide them if they were narrower.

jenny-wren

We pulled up a floorboard or two and found a few bent microbore pipes so we've decided that, since we're replacing most of the flooring anyway, that we'll get the piping replaced. We figured that it's much better to upgrade it now than to have to worry about possible leaks once we've put down wooden flooring and it should be beneficial if and when we come to sell the house. The installer will guarantee his work for 8 years and the boiler guarantee is 10 years. Considering the quality of 'improvements' completed by previous owners of the house it seems like a sensible choice! Now we need to decide which boiler to get ... and dig out the heavy jumpers as we'll be without heat for a few days. Winter probably wasn't the best time to be getting the heating system replaced.

Owain_Moneysaver

moneyistooshorttomention wrote: »

I was told they would be harder to "flush" if need be. Obviously - I'm crossing my fingers they won't ever need flushing. If they do - then I'll presumably find out at that point whether it is indeed harder to do.

It is likely that the new boiler's warranty will require all existing pipes to be flushed with system cleaner before connecting the new boiler, or the manufacturer's warranty will be invalidated.

EssexExile

Our microbore heating has been working fine since the 70s, it seems daft to have all the disruption of changing it if it's working ok.

jenny-wren

EssexExile wrote: »

Our microbore heating has been working fine since the 70s, it seems daft to have all the disruption of changing it if it's working ok.

That was our original thought but we've discovered so many botched jobs in the house that it's probably not worth the risk. Changing to gas will increase the pressure in the pipes. Despite working apparently well with an oil-fired vented system, that might not be the case with gas. We've had burst water pipes before and I don't ever want to have to go through an experience like that again!

thescouselander

Microbore pipes shouldn't be a problem if they're working now. We have it in our house and it works fine with our WB 36 CDI Compact and we got a 10 year warrantee as we used a WB accredited installer.

jenny-wren

thescouselander wrote: »

Microbore pipes shouldn't be a problem if they're working now. We have it in our house and it works fine with our WB 36 CDI Compact and we got a 10 year warrantee as we used a WB accredited installer.

Hmm, maybe we need to have a rethink as it's going to add over £1k to the bill. The house was built in 1959 but I have a feeling that it may not have had central heating installed until later.

There is one obvious small compressed section of microbore pipe just below one of the radiators. I'm not sure if this can be fixed without taking the whole section of pipe out.

Are there any plumbers about that can give any advice or experience of the percentage of microbore systems that have caused problems with a combi boiler. If it's only 1 in 10 then we might take the risk (and put the money saved towards fixing something else on the list of things that need to be done).

We need to make final decisions by Monday. :shocked: