Converting to a combi - how likely are leaks?

[gerbils]

Just about to get a new boiler - current one is 1985, same age as the house. However I am reading horror stories of pipes leaking due to increased pressure.

How likely is this on a 1980s property and is there anything I can do to mitigate this?

 

[Alec_t]

Compression joints might need nipping up. You might also want to have a good look at your rads if you're retaining those. Any rust spots could indicate potential weakness.

 

[Madrab]

Depends on whether the old system was sealed or open vent. If it was open vent then changing over to sealed can cause issues You would need to pressure test the system and leave it over a couple of days to see of any of the fittings leaks or not.

2 ways to do it -
1) use a pressure testing pump, seal the system and pump pressurise system and leave it and monitor the pressure over a day or 2.
2) seal the system , attach a mains filling loop and gauge and pressurise with the mains and seal off and again monitor pressure over a couple of days

 

[terryplumb]

Depends on the condition of existing installation. For you to have a " horror story" on your hands ,your plumbing would have to be in a very poor state to begin with.
Slight weeps on compression fittings are quite common.

 

[gerbils]

Depends on whether the old system was sealed or open vent. If it was open vent then changing over to sealed can cause issues You would need to pressure test the system and leave it over a couple of days to see of any of the fittings leaks or not.

2 ways to do it -
1) use a pressure testing pump, seal the system and pump pressurise system and leave it and monitor the pressure over a day or 2.
2) seal the system , attach a mains filling loop and gauge and pressurise with the mains and seal off and again monitor pressure over a couple of days

Yes it's open

 

[fixitflav]

Just about to get a new boiler - current one is 1985, same age as the house. However I am reading horror stories of pipes leaking due to increased pressure.

How likely is this on a 1980s property and is there anything I can do to mitigate this?

Any reason to go for a combi, other than the quoter pushing it? You could just replace with a modern heat-only boiler and you don't have the risk.

 

[gerbils]

Any reason to go for a combi, other than the quoter pushing it? You could just replace with a modern heat-only boiler and you don't have the risk.

More space and better water pressure for our showers - other than that, no reason.

 

[Murdochcat]

If you keep your existing set up and later get solar panels, you could fit an immersion divertor so your surplus energy heats hot water FOC

 

[Mottie]

We converted our open vented system to a sealed system and unvented hot water in 2017. We had pinhole leaks in two of the upstairs rads when the system was pressurised but then again, they were the only original rads left in a system that was fitted in the sixties so they were at least 50 years old! The rads that had been replaced in the nineties when we moved in were fine.

 

[sjmac]

In nearly 30 years doing the job I can only recall 2 serious issues when I've done conversions.

 

[BigSnoopy01]

Normally it's fine. If a rad fails it was going to fail very soon anyway. Better to fail whole there's a plumber about.
More Important is the system being flushed very very well. Avoid quotes from people who don't discuss the system being flushed and it taking a good amount of time.