Central Heating Boilers:
 

My daughter needs a new gas combi boiler in her flat in London. Are they any particular makes to avoid? One plumber recommended an Instagas Boiler. I have never seen these advertised in the Trade mags. but Plumbase sell them. He said they are really well built and reliable? Are Biasi any good? Any help with this would be gratefully appreciated.

Re: Central Heating Boilers:
 

I was recommended to get a Worcester (owned by Bosch) and they seem to get good reviews. 5 years old and, touch wood, no problems.

Re: Central Heating Boilers:
 

Worcester Bosch are a good boiler and made in UK ( In Worcester of all places !). Vaillant make good boilers but charge like a wounded bull for them ( and read experiences below).

The older cast iron boilers were not so efficient as modern condensing boilers but they used to last centuries without problems. Modern boilers are only designed for a service life of 6 to 7 years. I read an article once to tell people not to go for a new boiler under the government scheme if they had a good old boiler that was still working because it did not make economic sense to trade in a boiler that would last forever and was 85% efficient for a new boiler that was 90% efficient and that will be 2 grand thank you and will only last less than 10 years. We have a Vaillant condensing boiler (the dogs dangly bits of boilers and priced to suit) fitted to our house when we moved in 20 years ago, still working but it is a bit like triggers broom, 3 new fans ( £180 a time ), 2 new pressure switches ( £90 a time ), one new water pump (£200), one new main printed circuit control board ( £300) and a new heat exchanger ( £400 ). The problems with the fans was mainly caused by the original installer sloping the horizontal balanced flue pipe back towards the boiler instead of away from it - this meant that condensate from the flue drained back into boiler onto the hot heat exchanger casing, flashed into steam and turned the normally dry area where the fan sits into the equivalent of a steam room, this corroded the (unsealed) fan bearings and the PCB (despite ACF-50 and WD-40 on the board and connectors). You can buy bearings from Cromwell or RS for a few quid but have to destroy the fan to get to bearings as plastic fan impeller is glued on and the rotor of the variable speed motor is welded on to the other end of shaft).

In our older house we had a Potterton back boiler that was fitted before WW2 and still working fine 50 years on.

No matter how 'efficient' an expensive new condensing boiler is compared to an older one it will take longer than the new boiler is gonna last to get your money back, then you have to get another new one, and prepare for some hefty repair bills on you new flimsy model.

Re: Central Heating Boilers:
 

I'm on my second Vaillant boiler. To be fair I did move house.
Both properties had a prehistoric boiler when we moved in. The house we are in now had one that was part of the worktop in the kitchen. WTF. It was practically condemned on our survey.


Anyhow I digress.
First house we were there nearly 5 years. No issues whatsoever.
Second house been there just over 3 years. No issues whatsoever.


Had one of these fitted in both. Vaillant ecoTEC Plus 835 Combi Boiler.

Re: Central Heating Boilers:
 

baxi back boiler installed some time in the 80's, serviced once a year and had only one water pump replacement and one thermostat. i'm looking to get a combi installed but only for the space saving. otherwise i'm happy with the baxi.

my father was a plumber and always said to get a Worcester combi as the flow rates were better than the cheeper ones.

if you have a household that is continually using hot water then it might be best to get a proper boiler and hot water tank otherwise your combi will always be switching on/off which causes quicker failure. same goes if your central heating is on all the time then with a back boiler you always have hot water rather than making the combi work twice as hard.

personally its the space saving that i want as the hot water tank takes up a large corner of my kitchen.

Re: Central Heating Boilers:
 

Beware of plumbers who condemn old cast iron boilers. They may well be after your money to replace then with a shiny new one out of greed or laziness. Happened to us - elderly Potterton floor-standing job in the house when we moved in, we played Russian Roulette with Yellow Pages after finding the kitchen full of carbon monoxide one morning and the guy took one look and said it had to be condemned* as it was unserviceable. Had a second opinion (thankfully) and this guy rolled up his sleeves and got filthy vacuuming out all of the soot that had built up. Once done it was fine!

When we remodelled the house we did replace the boiler but only because the output was not up to the new layout. Shame. The new Potterton we have now has had new fans, PCBs, heat exchangers, etc. too because the builders installed it wrong. Now fixed and, touch wood, it's been fine for over five years with minimal annual servicing costs. It's eleven years old now so I dare say it may be on borrowed time...


*oddly, despite being Corgi registered (it was a few years ago) the idiot that condemned the old boiler did not actually condemn it. He left it going... Something the second opinion guy was disgusted at and said he would complain about. However, the same a-hole did some shoddy work for my neighbour a few years later (I recognised the van) as a subbie on their extension. They were not happy either.

Re: Central Heating Boilers:
 

Combi boiler pretty much twice as complicated as a normal boiler. Has separate heat exchangers for CH and HW with the added problem of the pressure switch that is supposed to sense when a tap or shower is turned on and fire up the burner, but can be very temperamental. Combi also only good with smaller properties with only a few possible hot water outlets. I replaced our 20 year old pressurised Vaillant mild steel glass lined hot water tank last year with a Sadia- Heatrae stainless tank. Got fed up of replacing the sacrificial anode at £50 a pop, and worrying when tank was going to corrode and flood the house. Had a glass lined mild steel tank fail in one house and it made an awful mess, never trusted them since. Mind you the tank failed in a soft water ( acidic) area, hard water is much less corrosive, even copper pipes do not survive as long as they should in soft water and develop pin-holes - not good news. Good news is that we now live in hard water area.

Re: Central Heating Boilers:
 

hard and soft water is not dictated by the acidity of it but both often go together. soft water has less salts than hard water.

for domestic tap water to corrode copper piping the acidity would have to be constantly under a pH of 2 which you would notice straight away if you drink it.

living in a hard water area is bad as it has a higher content of salts which build up in pipework etc.etc. soft water areas have no such problem.

Re: Central Heating Boilers:
 

We have a Worcester,at two years old. The plastic pipes were dripping, service tech tried to tighten them and the joint disintegrated. A few years later it starts to act up. Because the control board had water damage we could not get British gas who then had the contract to replace the board. the boiler worked but when hot water on would keep switching off the burners until the hot water ran cold and then turn them back on. The only way to fill the tub was to turn the tap 30% open.


Different fault and the young British gas tech had a water disaster and blew the control board. Yippee in goes a new one and the fault fixed.


Worcester boilers.....Supposed to be good, Ours must have been a friday job. Leaky pipework. 3 diverter valves in 10 years, Even though the control board is fixed and the burners stay on. It cannot heat the hot water for the tub at full flow.

Re: Central Heating Boilers:
 

The generally accepted definition of hard water is water containing dissolved calcium from limestone areas. Soft water is pure water with fewer dissolved solids.

Water with ph less than 6.5 can cause corrosion, hard water coats the inside of the pipes (that is the bad news) the good news is that the calcium coating prevents corrosion of the pipes. acidic water ph<7 continually tries to remove the protective oxide coating from metal pipes, hard water covers the oxide coating with a protective layer. Lead pipes in water supplies were not really a problem in hard water areas because inside of pipe was protected by limescale, in soft water areas though they water dissolved the lead and people were drinking it. My brother used to work for a water purification company who supplied treatment equipment to water suppliers like Severn Trent, Yorkshire water etc. They preferred Hard water to soft as it was easier on their equipment as it reduced corrosion problems. If your boiler or heating system has any aluminium in it you should not use soft water, if you have a water softener fitted to your house you should take off the water for heating system ( filling loop ) before the softener. The anti-corrosion heating system additives like Fernox raise the ph of water to protect pipework and boilers.

http://www.kamco.co.uk/GuidanceNotes...structions.pdf

https://www.combimate.co.uk/sof****er-corrosion.html


https://www.water-research.net/index...-zinc-and-more