Risk of leaks on a combi conversion?

[hunbahubba]

My regular boiler has packed up and I'm weighing up replacing with a new regular boiler vs converting over to a combi. I'd prefer to go for the combi but my only worry is the risk of leaks on pressurising the system.

Most of the pipework and radiators are from the 1960s. I've got nice tiled and wood flooring downstairs, so I'd be pretty guttered if I ended up having to rip up the downstairs floors to track and trace a leak or replace the central heating pipework.

Can anyone give me an idea of what the likelihood of an issue is on this age system? Am I opening a potential can of worms, or just being overly cautious?

 

[Madrab]

Any reputable installer should be able to pressure test the current system to see if it will handle moving to a sealed system. That being said, if it was me I would have to caveat the conversion as there could be no guarantees that something old might not fail further down the line.

 

[Murdochcat]

If you think you might install PV on your roof, you should keep the existing set up, then you can use a divertor to send excess energy to the immersion and get lots of free hot water

 

[hunbahubba]

Any reputable installer should be able to pressure test the current system to see if it will handle moving to a sealed system. That being said, if it was me I would have to caveat the conversion as there could be no guarantees that something old might not fail further down the line.

Thanks. In your experience what kind of risk am I running with a 60 year old system. Is the like a 50 50? 1 in 10? Once on a blue moon kind of thing?

 

[Emit]

Intergas do a combi that can still be used as open vent.

 

[Madrab]

Thanks. In your experience what kind of risk am I running with a 60 year old system. Is the like a 50 50? 1 in 10? Once on a blue moon kind of thing?

If it's pressure tested properly then the risk drops significantly but really hard to put a figure on it, each one is different and very reliant of site inspections, condition of the rads and fittings, system water condition etc, TBH that can only really be gauged by seeing it.

 

[Mottie]

Thanks. In your experience what kind of risk am I running with a 60 year old system. Is the like a 50 50? 1 in 10? Once on a blue moon kind of thing?

I had leaks when I converted to a sealed system but only pinholes on the 60 year old rads. I think I read on here recently that one of the plumbers carries out a pressure test before such a conversion but had only seen it once or twice in about 20 odd years.

 

[Jurassicspark]

As above, get someone to pressure test the current system. No ifs or buts.

 

[footprints]

I would certainly replace any old radiator valves, copper pipe will last many years assuming you have not had any problems with it so far.
There were some really dodgy pipes around after 1965 when Rhodesia declared UDI and cut off the supply of copper but by now they should have shown up if you have them. Any copper that pinholes or rusts is a big red flag!

 

[muggles]

The Intergas ECO RF will run open vented, as will a Navien NCB700 (with a bit of knowledgeable fiddling in the installer settings).

 

[JackK]

The Intergas ECO RF will run open vented, as will a Navien NCB700 (with a bit of knowledgeable fiddling in the installer settings).

I have steel 2 inch pipework and also very worried about this as well - Can pipiework irrespetive of copper or steel be pressure tested?

Would old school pegler TRVs also be able to handle 2 bar sealed pressure

I am told that open vent pressure is something like 0.1 bar so its 20 times as much - not great is it

 

[mcmoby69]

Intergas or separate the system and new boiler using a plate heat exchanger.

 

[sjmac]

Any reputable installer should be able to pressure test the current system to see if it will handle moving to a sealed system. That being said, if it was me I would have to caveat the conversion as there could be no guarantees that something old might not fail further down the line.

With the greatest of respect- if you pressure test and it leaks how are you any better off. In 25 years I've only had 2 maybe 3 significant issues. How many customers are going to pay you you to prove they have a leak prior - zero

 

[JackK]

With the greatest of respect- if you pressure test and it leaks how are you any better off. In 25 years I've only had 2 maybe 3 significant issues. How many customers are going to pay you you to prove they have a leak prior - zero

Thanks so what do you normally do? Move everyone to sealed and rely on the 2 / 3 problems over 20 years or something a bit more sceintific

 

[sjmac]

Balance of probability is it won't leak. If it does then you had a leak anyhow and the work has just highlighted the fact.

If it was a massive issue, trust me you would know. And if If was a massive issue Watchdog or the customer crusaders Martin Lewis or Allbright would let you know. Yep a risk albeit a minor one