Boiler advice needed please

NRGMAN

https://forums.moneysavingexpert.com/discussion/comment/82050199#Comment_82050199

Thank you. Yes, it's the 25 kW one.

ComicGeek

https://forums.moneysavingexpert.com/discussion/comment/82049614#Comment_82049614

Rather than an air-to-water heat pump, which is likely to need modifications to pipework and radiators to run efficiently, I would install air con units. One indoor unit in the bedroom, one in the living - multi split externally. Or condenserless heat pumps from Powrmatic or similar if no external space for the condenser.

Much higher heating efficiencies, much quicker response time, much cheaper installation, and you also get cooling in the summer if you want it. Once the shower hot water usage is taken out of the equation, air-to-water heat pumps don't really make sense.

But I would probably just install a replacement gas fired combi boiler at this stage, and wait a while before making any major changes.

Jumblebumble

https://forums.moneysavingexpert.com/discussion/6673917/boiler-advice-needed-please

My gas guy says that WB are the least troublesome of all the boilers he repairs

He says go for 2000 at a minimum as it has an aluminium heat exchanger depending on how big your place is

NRGMAN

https://forums.moneysavingexpert.com/discussion/comment/82053168#Comment_82053168

Thank you. Yes, they certainly seem to have a good reputation. I think my mind is pretty much made up now.

Albermarle

https://forums.moneysavingexpert.com/discussion/comment/82053168#Comment_82053168

If you ask 10 gas safe engineers which is the best/most reliable boiler they work on, you will get 10 different answers. They all have their favourites.

NRGMAN

Reporting back here after quite some time, just a few days before, what was to be, my installation date. This has now been cancelled, unfortunately since it has been identified (somewhat late in the day) that my current gas pipe is only 15 mm in diameter. Modern boilers (the majority, anyway) would require a 22 mm pipe minimum to prevent pressure drop. When I had my boiler installed, way back in 1997, the pressure was not pre-set and instead determined by the engineer in accordance with this pipe. Seems that can't be done now so it's bye-bye WB Greenstar 4000.

Anyway, I have explained the situation to another gas engineer who is visiting me this coming Monday to discuss options. Whatever those will be. I've informed him that I am not prepared to start ripping my house apart to upgrade the gas pipe and he completely understands that. Not sure if external piping around the building would be an option as I have neighbours to consider, so I am thinking that the only solution for me would be to go for a heat-only boiler with a hot water cylinder. I am hoping that needing gas for only the boiler (I have an electric shower, no gas hob), living on my own in a one bedroom ground level flat with six radiators will go in my favour.

Has anyone else been in this or a similar situation? What was the outcome? Thanks.

Albermarle

AIUI, the critical issue is the pressure drop from the meter to the boiler should be less than 1mBar.

If you are not changing to a more powerful boiler than you have now, then if the pressure drop is less than that, you should in theory at least be OK.

However some boiler manufacturers and installers may well just say it has to be 22mm to be on the safe side.

I am not a Gas safe person, so these are only layman's comments and others may well disagree.

NRGMAN

https://forums.moneysavingexpert.com/discussion/comment/82111496#Comment_82111496

Thanks. I am no boiler expert either but hopefully this gas engineer I am seeing Monday will have it all figured out. He seems a genuine guy and has more than 20 years experience and I did find his positivity reassuring when I spoke to him on the phone. I reckon he will most likely suggest the heat-only boiler under the circumstances.

Albermarle

https://forums.moneysavingexpert.com/discussion/comment/82111686#Comment_82111686

With only 6 radiators in a small house, and needing hot water for only one, you should be fine with a 12 KW boiler, so half the power that the combi would have been.

FreeBear

https://forums.moneysavingexpert.com/discussion/comment/82111496#Comment_82111496

There are calculations that can be done based on distance & maximum boiler rating to determine what size pipe is required. 15mm can be used for a short distance, and indeed, most boilers come with a 15mm fitting for the gas supply.

When I was going through the initial thoughts on boiler location, routing of the gas supply was one of the main considerations. Could have installed the boiler in a utility room at the back of the house. But routing a 22/28mm pipe from the gas meter at the front would mean lifting floorboards, ripping out kitchen units, and a whole bunch of other work. In the end, ran a 22mm across the outside front of the house and installed the boiler just inside the front door. According to my calculations, an ~8m run should have been 28mm for most of the distance. But pressure drop was measured at just under 1mb - BUT the test was only ever done with the boiler running at 50% capacity.

Whilst I would normally suggest a heat pump as a viable alternative to a gas boiler, being in a flat adds a whole raft of additional problems to an installation. Shame really, as a HP has the potential of being cheaper to run over the course of a year.