We had our tank removed from the loft to a new WB Lifestyle 8000 40KW combi. Our pipework is microbore which the plumber obviously doesn't prefer but he didn't suggest replacing it all even though I know he was on the lookout for as much work as possible. Get alternative quotes ASAP. (edited)
If you are unhappy with your plumber before he has even started - get another.
Hi - I'm an assessor in plumbing. The new system does work at a higher pressure compared to your old one and you would have to manually fill the new system up if you have a leak of cause otherwise the boiler wont work at all! Currently you could have a leak (downstairs) and not know as it tops itself up.
You/He could pressure test the existing pipe work overnight at 3 to 4 bar and see if anything drops.
I would probably not swap the existing pipework and hope for the best. (edited)
The plumber is pulling a fast one. But have you checked your old radiator and pipework for debri ? As new combi boilers have lots of small parts and rubber seals. If there is any iron oxides ie rust - iron particles floating around these will sooner or later clog or cause leaks on the boiler. I would recommend a powerflush before getting a new combi fitted to a old system. Better to get this done from a company that does powerflushing then any old regular plumber.
I use to install a lot of combi changeovers in the past. On the heating side there isnt that much extra pressure on the heating side. But if you have a copper tank the hot water pipes will have a lot more water pressure in the pipes. This is the one you have to be more aware of as any bad joints ie compression or tap connection can start to leak if not tightened up in the first install. This was the most common issues I ever encountered. But rarely happens. I would get flush first then install the boiler and worry about any possible leaks afterwards as they unlikely to occur.
If it copper piping then he’s talking utter crap but then again I’m not a plumbing expert.
The green stuff might be old oxidised flux or signs of a leak?
Never have a single quote /opinion. Some plumbers only like certain boilers. New combi boiler, removal of hot tank etc cost me £3200 last month using 99% of old plumbing but was an old pressured system (edited)
We went from a hot + cold water tanks system with an ancient floor-standing boiler(tanks removed etc) to a Combi several years ago. There were some minor pipework changes around the boiler location - but nothing changed for the rest of the house.
We are about to replace a Storage Boiler (18 years old from the house being new) for a Intergas Xclusive 30KW - it is being done by a mate, and he will be doing the plumbing in a way that if we decide to put in a unvented cylinder - it won't need all the pipework redoing to meet this.
The Intergas can operate as a Combi or a System boiler just by changing a setting hence what has attracted us to this - it will be put in on X plan Priority Hot Water as we are hopefully getting 6kw solar installed with 10KW storage at some point. We have Microbore 10mm throughout for our heating and to replace it would mean ripping out hand plastered coving downstairs and ripping up flooring (tiles/laminate) upstairs so isn't really an option - at best we may put in a return leg for the hot water as this will be under the landing which is carpeted.
Regarding yours - you can do an air pressure test - look up Urban Plumbers on You Tube
when we bought our house, we had a hot water tank upstairs, which was fed by a boiler downstairs. we got the hot water tank removed and replaced with a new combi boiler. the combi boiler was located on the opposite wall to where the old boiler was situated. the plumber had to re-route a lot of the pipework as the old pipework could not be fully used because the way combi boilers are set up, the pipe work is not the same. so i am not surprised that he has told you he needs to do new pipework.
When we had combi boiler fitted some years ago didn't replace any of the radiator pipe work and didn't leak. Still the same pipe work now although we have since changed a couple of rads.
Baxi are highly thought of, we've had the same heating engineers service our house and the previous one for the last 10 years, and they won't fit anything else.
We went from a open vent combi (very unusual, but was an optional setup for the Worcester 24cdi back in the day) to a Baxi 40 Platinum. Other than having to do some thinking to re-route the replacement 22mm gas pipe (old was 15mm), and a bit of an incident when we all realised that some of the old TRVs in this house are one way, the rest of the existing 20+ year old piping was left in situ. No issues with the increase in pressure. (edited)
The radiators don't go up hugely in pressure, it's something that's adjusted from the boiler itself.
"The normal boiler pressure when the central heating system has cold water should be between 1 and 1.5 bar. Most manufacturers recommend an optimal system pressure of 1.3 bar" heatingforce.co.uk/blo…be/
When we had our gravity system changed to comb, the old copper pipes to radiators stayed. We did get them properly cleaned out though and added a muck trap into the circuit which gets cleaned out every year.
He is correct about the 1bar pipework. It is true that the system may leak at 3bar in places obvious or just a compression joint under the floorboards. But there is a way to test this via a pressure test prior to the install. Obviously you would have to pay for this & it would be over a couple of hours. So expect £120 minimum.
The pressure test would be done much higher than 3 bar. Maybe up to 10bar.
However, you are installing new pipework which is sensible without testing & it makes it easier to install new rads & valves but costs more because of the pipework.
The green on copper is usually caused by flux that has not been cleaned off & if is it covering a large area may indicate a leak of sorts. Flux is corrosive,so it could cause the problems he mentioned.
Of course he gets cashback on a boiler & your actions cost him a bit of money. If he knew you were going to buy the boiler then he probably would have put the price of the install up.
A little bit off subject, but have you done your homework before converting to a combi boiler? I did, and I went for an unvented cylinder - the reason being that I'm planning to have solar panels installed, and possibly replace the boiler with a heat pump. I'll use the excess power from the solar panels to heat the water in the cylinder, and a heat pump would need that cylinder (it wouldn't provide instant hot water like a combi does). Just a thought :/ (edited)
I wrote an essay of a reply for you but it got deleted by hukd and there’s no way of seeing what was wrong with my reply or getting what I said back to paste here 🏻
18 Comments
sorted byOur pipework is microbore which the plumber obviously doesn't prefer but he didn't suggest replacing it all even though I know he was on the lookout for as much work as possible.
Get alternative quotes ASAP. (edited)
You/He could pressure test the existing pipe work overnight at 3 to 4 bar and see if anything drops.
I would probably not swap the existing pipework and hope for the best. (edited)
But have you checked your old radiator and pipework for debri ? As new combi boilers have lots of small parts and rubber seals. If there is any iron oxides ie rust - iron particles floating around these will sooner or later clog or cause leaks on the boiler.
I would recommend a powerflush before getting a new combi fitted to a old system.
Better to get this done from a company that does powerflushing then any old regular plumber.
I use to install a lot of combi changeovers in the past. On the heating side there isnt that much extra pressure on the heating side. But if you have a copper tank the hot water pipes will have a lot more water pressure in the pipes. This is the one you have to be more aware of as any bad joints ie compression or tap connection can start to leak if not tightened up in the first install. This was the most common issues I ever encountered. But rarely happens.
I would get flush first then install the boiler and worry about any possible leaks afterwards as they unlikely to occur.
The green stuff might be old oxidised flux or signs of a leak?
The Intergas can operate as a Combi or a System boiler just by changing a setting hence what has attracted us to this - it will be put in on X plan Priority Hot Water as we are hopefully getting 6kw solar installed with 10KW storage at some point. We have Microbore 10mm throughout for our heating and to replace it would mean ripping out hand plastered coving downstairs and ripping up flooring (tiles/laminate) upstairs so isn't really an option - at best we may put in a return leg for the hot water as this will be under the landing which is carpeted.
Regarding yours - you can do an air pressure test - look up Urban Plumbers on You Tube
We went from a open vent combi (very unusual, but was an optional setup for the Worcester 24cdi back in the day) to a Baxi 40 Platinum. Other than having to do some thinking to re-route the replacement 22mm gas pipe (old was 15mm), and a bit of an incident when we all realised that some of the old TRVs in this house are one way, the rest of the existing 20+ year old piping was left in situ. No issues with the increase in pressure. (edited)
"The normal boiler pressure when the central heating system has cold water should be between 1 and 1.5 bar. Most manufacturers recommend an optimal system pressure of 1.3 bar"
heatingforce.co.uk/blo…be/
When we had our gravity system changed to comb, the old copper pipes to radiators stayed. We did get them properly cleaned out though and added a muck trap into the circuit which gets cleaned out every year.
The pressure test would be done much higher than 3 bar. Maybe up to 10bar.
However, you are installing new pipework which is sensible without testing & it makes it easier to install new rads & valves but costs more because of the pipework.
The green on copper is usually caused by flux that has not been cleaned off & if is it covering a large area may indicate a leak of sorts. Flux is corrosive,so it could cause the problems he mentioned.
Of course he gets cashback on a boiler & your actions cost him a bit of money. If he knew you were going to buy the boiler then he probably would have put the price of the install up.