Switch oil to gas with microbore piping?

[DoNotUseFullName]

We just had someone out to advise on switching from oil heating to gas. He advised that microbore piping could cause issues with a gas boiler, and said if it was him he'd update the piping to standard size at the same time. We have solid floors so this is no small job breaking up concrete in the house. He even said himself that this was a big job he wouldn't take on himself, and suggested upgrading the oil system instead, as it's quite old.

What are people's thoughts on this?

 

[old duffer]

microbore was created by the devil....it is against the laws of humanity to use it

 

[cozzmic]

Nothing wrong if installed correctly. My system was put in about 1974 and works fine. Won't work for air source as too small but originally on an AGA fan flued gas boiler.

 

[ericmark]

My oil works very diffrent to gas, oil turns on/off, gas turns up/down, but up/down should work better than on/off. As the flow through each radiator is a lot slower.

 

[Madrab]

Nothing wrong with microbore if it's nice and clean and been well looked after and the system capacity isn't large. If it's even slightly dirty, or the system is a reasonable size with average or plus sized rads then I'd recommend to not take the chance and repipe.

 

[gas112]

if it works perfectly ok with oil then it should work perfectly ok with a gas boiler worked on thousands of microbore systems on gas that work perfectly ok

 

[fixitflav]

We just had someone out to advise on switching from oil heating to gas. He advised that microbore piping could cause issues with a gas boiler, and said if it was him he'd update the piping to standard size at the same time. We have solid floors so this is no small job breaking up concrete in the house. He even said himself that this was a big job he wouldn't take on himself, and suggested upgrading the oil system instead, as it's quite old.

What are people's thoughts on this?

I don't see how the pipework knows whether the boiler uses oil or gas.

 

[DoNotUseFullName]

I'm not sure how well the system has been maintained as we're not in property that long, but at the very least we haven't had any issues. All the rads get nice and hot, no cold spots. It looks like only the downstairs rads have the 10mm pipes too, upstairs seems to be standard sizes. There's only 7 rads in the house so capacity is not large.

I don't see how the pipework knows whether the boiler uses oil or gas.

:shrugs:

 

[Madrab]

The system pipe size is not a consideration as to whether a gas or oil boiler can used. So your original chap sounds like he trying to use tech speak to get a bigger job.

The only real issue you'll get into with mixed pipe sizes - sludge and crud not withstanding, will be balancing to make sure the rads all heat up at the same time, an experienced CH bod should deal with that without issue. If it's only 7 rads that'll why it was used, perfectly ok for that size of system as long at the rads fed by the 10mm, aren't huge ones.

 

[fixitflav]

:shrugs:

Shrug away

 

[Fred Blogs]

I live in a concrete floored bungalow built in 1982 and we have 8mm microbore. It works fine and we have a gas boiler that has been in for 17 years. I have changed all the rads in the house over a period of 3 years some for doubles rather the singles that were there. I don't particularly like our microbore as the pipes have been brought down from the loft manifolds down the walls in plastic square conduit so it doesn't look particularly nice. I have disguised most of it when I have papered various rooms. But the point is that it works and works well. We certainly haven't had any problems either with the pipes or the boiler and assume the previous occupants didn't either. We have 9 rads two of which are doubles. I have installed a Magnaclean filter and I have bunged a couple of bottles of cleaner in over the years. To change it to 22/15mm would be a major major upheaveling undertaking not to mention the crippling expense. There is absolutely no way that is going to happen whilst I am here and the same applies to heat pump heating which in my opinion doesn't work anyway.

 

[Johntheo5]

Pump head required may be 2 to 3M higher due to much greater gas boiler heat exchanger head loss but if existing (oil) system is running at ~ 3M head, like mine, then not a problem as system gas boiler pumps have a 7M pump head.

What boiler have you in mind, some, like Vaillant have a internal bypass that can only be set to a maximun of 4.5M.

 

[old duffer]

Nothing wrong if installed correctly. My system was put in about 1974 and works fine. Won't work for air source as too small but originally on an AGA fan flued gas boiler.

a sail ship still floats and is safe for passage. An aircraft is much quicker...they can both take you to a destination therefore sail ships are as good
aircraft

 

[Johntheo5]

10mm microbore is hardly being used for the main flow/return??, 15M of 10mm (8.6mm ID) flowing a fairly modest 15LPM would require a 36M (3.6BAR) circ pump, a 6M circ pump will circulate < 6.0LPM.

 

[Agile]

The radiator system does not know where the heat is coming from.

Nor does the boiler know where its heat is going.

Before making any changes it would be sensible to do a thermal survey of the heating using the existing oil boiler to see if a gas boiler is likely to be able to match the heating output.