New boiler, best system?

[RF Lighting]

Unfortunately my parents have finally let grittish bass get into their heads and have been scared into wanting a new boiler installing at their house.

They currently have a 36 year old glow worm space saver MKII boiler which has never missed a beat apart from an occasional replacement thermocouple which BG now refuse to service. Maybe it’s me being cynical, but is this a tactic to make sure the boiler breaks down so they can sell a new one?

The current setup is open vented with gravity hot water and an S plan heating system with 3 zones (upstairs, downstairs and garage) serving 13 rads.

They currently have a pumped shower from the indirect cylinder and would also like to retain an immersion heater incase the boiler packs up.

They’d obviously like to keep cost and disruption to a minimum. Is there any reason for them to ditch the open vented system, and if so what advantages would a sealed system offer?

 

[muggles]

Dump BG and all your/their problems will be solved. They can keep the Space Saver, save money on not paying the annual maintenance contract they're almost certainly on, and find a nice friendly local engineer to keep things going for them. That's the low-cost low-disruption option.

If they do go for a new boiler, then sealing the system has some advantages - much less chance of corrosion, easier to maintain - and the potential disadvantage of it exposing weaknesses in the old heating system, leading to the possibility of leaks. Rare for this to happen, but not impossible.

 

[vulcancontinental]

The only thing I'd add to muggles reply is to emphasis be wary if there is any pipework buried below screed and pressurising during conversion to a sealed system make any leaks difficult to find and fix.

Have they had many pump replacements? If not during 36 years there's not much wrong with the open system layout as is.

 

[bernardgreen]

Maybe it’s me being cynical, but is this a tactic to make sure the boiler breaks down so they can sell a new one?

Yes it almost certainly is. The profit from installing a new boiler is far more than the profit from replacing a thermocouple.

Changing the system will involve some minor changes in life style, taps with mains pressure water behave differently from the same tap on a gravity system. Young people will adapt quickly, older folks may not.

 

[ianmcd]

As @muggles says, ditch BG they are just a sales outfit, if the boiler is working fine get a relationship with someone that knows older systems to keep it going, hardly a hard job to swap the thermocouple out if needed

 

[RF Lighting]

As @muggles says, ditch BG they are just a sales outfit, if the boiler is working fine get a relationship with someone that knows older systems to keep it going, hardly a hard job to swap the thermocouple out if needed

I’ve already persuaded them to use a local independent fitter to install the new boiler, but unfortunately they have heard one too many scare sales stories are now convinced that the old boiler is going to break down and that replacing it is the only option. They are also saying that a new boiler will be more efficient, which of course it will, but don’t seem to understand that the increased efficiency is going to take an awful long time to offset the cost of the new boiler, and it might even be life expired before its paid for itself.

The only thing I'd add to muggles reply is to emphasis be wary if there is any pipework buried below screed and pressurising during conversion to a sealed system make any leaks difficult to find and fix.

Have they had many pump replacements? If not during 36 years there's not much wrong with the open system layout as is.

I re plumbed the upstairs heating about 5 years ago as it was a 1/2” one pipe system. I don’t think there would be any problem pressuring the system at all, but is there actually much benefit in doing so?

I replaced the pump 5 years ago purely because it used to be under the floorboards and I moved it to inside the boiler cupboard, but it was still working fine and not blocked. I think the system is pretty clean. It has a magnaclean and is properly dosed up with inhibitor.

 

[RF Lighting]

Changing the system will involve some minor changes in life style, taps with mains pressure water behave differently from the same tap on a gravity system. Young people will adapt quickly, older folks may not.

Why would the taps need to be mains pressure? Could the indirect cylinder not be retained even if they were to change to a sealed heating system?

 

[bernardgreen]

Could the indirect cylinder not be retained even if they were to change to a sealed heating system?

My apologies for not being clear. ( lazy typing )

Yes the indirect cylinder fed from a cold water cistern can be retained, I should have made that clear.

They are also saying that a new boiler will be more efficient, which of course it will,

It might not be much more efficient, most boiler efficiency values advertised are for the boiler when operate in condensing mode.

The boiler can only operate in condensing mode when the water returning to the boiler from the radiators is below the dew point temperature.

Only if radiators are large enough to heat the rooms adequately with the water returning to the boiler below the dew point temperature can the boiler operate in condensing mode.