Replace Combi Boiler or repair?

Blueruby

To give a bit of background, we have a Glowworm 30cxi boiler installed in 2005 approx that has developed faults. Central heating works fine however there is no hot water. The diagnosis is that the diverter valve + motor needs replacing. Theres also a leak in a pipe inside the boiler. The cost of the repairs is in the region of £500. Couple of the boiler engineers suggest changing the boiler rather than spending that much money on repairs as other parts could spring up issues later on. All the tradesmen have come recommended by friends/ neighbours.
This will be a rental property so I don't want the hassle of a boiler breakdown when its occupied by tenants. So have decided to go with the advice of replacing the boiler.

Have been suggested a Baxi 600/30kw (7 year warranty), Magna clean sludge filter, Salus RF control, 7 new radiator thermostatic valves (some of the valves are damaged, plumber suggests changing all of the old ones to new). Total cost quoted is £1760. Is this boiler a good choice and does this quote seem reasonable?
Any other boilers to consider?

The property is a detached house with 5 bedrooms, 1 bathroom (with bath + walk in shower both mains fed), 1 shower room (with electric shower), 1 downstairs WC. Number of radiators in the house 5 single panel, 5 double panel, 2 towel rails. Is a 30kw boiler sufficient for the property?

In case I do up the loft or add a conservatory few years down, will this boiler still be good enough?

When I asked the plumber about getting a higher capacity boiler he said the gas pipe might not be wide enough and may need changing. He's coming to have a look today to be sure though. Shall update on that when I have more info.

Kindly let me know your suggestions please. Thanks.

[Deleted User]

I m no expert but I managed to replace my motorised diverter valve myself, for free because I was given a new valve. Before I replaced it , I could lock the valve in the open position so hot water and heating water going to the rads stayed on all the time, so in summer the rads were all turned off.
It was not a difficult job , no harder than wiring a plug. There was a small slider on my old diverter valve which allowed me to manually lock the valve in either off or on. Youtube is your money saving friend if you want to understand this
Draining the system was the fiddliest part but there are excellent instruction videos on Youtube covering the different central heating systems.
I did call a central heating plumber out who tried to con me in fitting a complete new boiler. I have little faith in many plumbers .

Cardew

This is a current thread on recommended combis https://forums.moneysavingexpert.com/discussion/5990445/advice-on-new-combi-boiler


It is unusual for a 5 bed detached house to have a combi, but as you only have one bathroom using water from the boiler, a 30kW combi should cope with the HW load.


When you discuss getting a higher capacity boiler, bear in mind that the maximum quoted output is usually for HW and it is less for CH water. For instance on the ATG combis - discussed in the thread above https://atagheating.co.uk/wp-content/uploads/2019/02/ATAG_Consumer_Brochure_s18_2019_v4.pdf the quoted outputs for various models are up to 41kW but the maximum output to CH is 31.2kW.

Blueruby

Thanks for your reply Houbara.
I don't feel confident enough to replace the diverter valve myself. Even if I did, theres the leak inside the boiler that needs fixing as well. As the property is going to be let to tenants, I dont want to take chances & would rather have a reputable gas engineer do the job although finding the one seems to be the hardest part.

Blueruby

Cardew wrote: »

This is a current thread on recommended boilers.


It is unusual for a 5 bed detached house to have a combi, but as you only have one bathroom using water from the boiler, a 30kW combi should cope with the HW load.

Oh is it? Didnt know that. The current boiler was already in situ when we bought the property.
What would be a better suited boiler for such a property if not a Combi?

When you discuss getting a higher capacity boiler, bear in mind that the maximum quoted output is usually for HW and it is less for CH water. For instance on the ATG combis - discussed in the thread above the quoted outputs for various models are up to 41kW but the maximum output to CH is 31.2kW.

Got that.
Thanks for explaining it in simple terms Cardew.
/QUOTE]

Blueruby

Plumber has had a look at the gas pipe & they are 22mm. To put in a boiler of bigger capacity, he suggests upgrading the pipe from the gas meter in the garage till the point where it can be easily accessed under floorboards on the first floor. Theres tiling on the bathroom floor & boiler is in a cupboard in the bathroom, so we can't change the gas pipe running below the bathroom floor without removing the tiles. He said theres not much labour charges for this only about £20 or so for the materials. He said this will give a boost to the boiler & as the kitchen has a gas hob, there won't be any fall in gas supply when both appliances are working to full capacity.
Is this all correct or am I being given stories?

He's suggested going for the Baxi 636 36kw combi. The cost of all materials and labour quoted is £1995. This includes fitting a magna clean filter and a Salus thermostat & replacing about 7 trvs on the radiators as well. If I wish to go with Baxi 630 30kw combi then the price would be £1760. Both have 7 year warranty. Are these boilers good & Is this quote reasonable?
Also are these compact Baxi boilers the latest in their range? Was told that the DuoTec & EcoBlue are older models & will be phased out soon. Is this true?
Appreciate your responses. Thanks.

Cardew

I can't see the point of running a larger bore gas pipe to a point on the first floor, when it still cannot be connected to a larger capacity boiler



The ‘Achilles heel’ of any Combi is supplying an adequate flow of hot water to a shower – particularly in winter – when hot water is being demanded elsewhere in the house – sinks, bath. As your second shower is electric, that is less of a problem.


I would get a couple more estimates.

Blueruby

Few other estimates that I could obtain

Plumber 1: Baxi DuoTec 40kw with magnetic filter £1900

Plumber 2:
Glowworm ultimate 30 C 30KW
7 year warranty
Supplied & fitted £1450

Vaillant
30KW Eco Fit 7 year warranty
Supplied & fitted £1600

Eco tec 7 year warranty
Supplied & fitted £1750

Eco tec pro 32KW 7 year warranty
Supplied & fitted £1850*

All require a system filter at £150 for the warranty but the 32KW pro needs a special filter (£230) to get its 10 year warranty


Are any of the above boilers good & does the quote seem reasonable?

Owain_Moneysaver

Houbara wrote: »

I m no expert but I managed to replace my motorised diverter valve myself, for free because I was given a new valve.

That's fine if it's a separate valve on a system with a separate hot water cylinder, but this is a combi boiler and the diverter is an integral and specific part of the boiler. Parts availability and Gas Safety regulations rule out DIY of this job!

Brewer20

I'm fortunate to have a local boiler installer close by, he's done work for other members of my family and friends. He has rental properties of his own and maintains local authority properties too. He always fits Worcester Bosch boilers and has very little if any trouble from them. Mine's warranted for 6 years with a filter fitted although I think the standard warranty is 5 years.

Still early days at 3 yrs in but it's been 100% reliable. Straight swap over, Salus control, two replacement radiators, new valves £2200, my son had his replaced came in at £1850 just the boiler swap with Salus control, both for 3 bed semis.


In both cases my old boiler was past it's best at 22 yrs old and my sons only 10 yrs old. My sons should have last longer but was told he could throw parts and money at it (was quoted £300 to fix a new control panel and new valve) but what next to go wrong?