Boiler broken, new build around the corner. What to do?

[Goodremy]

We're at a fix; any help will be welcome. Regular boiler has been condemned because of hole in casing but it was in good working condition. Currently we have 3 massive feeder tanks in the loft in opposite sides of the house; everything in this house is in twos as it was extended by previous owners and nothing was consolidated. We are planning a big renovation in 18 months and will be moving out while this is done. We were looking to install a system boiler then; we are a family of 6. Right now we don't have heating and hot water. The question is what boiler do we get? Having a system now will  cost £4300 and a regular will cost £2500. If we got the system boiler now, all pipework will need upgrading including the external mains. On the other hand a new regular boiler would use the current setup but we'll be using it for only a short time until we renovate. If we got the system boiler now, can it be disconnected (when we evacuate the house) for a year while the house is being built? Also what about storage? Will the inside mould? Our current cylinder is very old and doesn't make the most of our solar so we were looking to invest in a twin coil solar one. The two showers we have right now run on two separate pumps that keep breaking and drawing too much hot water that the hot water is finished only after two people have been in. We always hoped this current boiler would function until the big build. 

Edited December 5, 2022 by Goodremy
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[PeterW]

Not sure why you have such a disparity in pricing - what is the current boiler ..??

[Goodremy]

The current boiler is a regular boiler and the price is for replacing like with like. The higher price is for a system boilet. This includes boiler, invented cylinder, removing cold water tank from loft, upgrading pipes.

[Redbeard]

What do you mean by a 'regular boiler'? You refer to a difference between a 'regular boiler' and a system boiler, so I think by 'regular' you must mean a combi (instant HW; no cylinder). 

 

As a lot of solar-water-heating exponents found in the past you can 'de-combify' a combi, effectively by telling it that the cylinder which you install at a later date is another radiator. As long as the sizing will be right I would, in your position, install another combi now (if I am right that it's a combi you have now) and use it as a system boiler if you want a HWC when you have refurbed.

[ProDave]

1 hour ago, Goodremy said:

Regular boiler has been condemned because of hole in casing but it was in good working condition.

This sounds like a case of "it wasn't broke why did you mess with it"

 

What part of the casing?  Is it really a serious fault (gas or combustion products leaking) or just an outer case?

 

I would seriously look at getting it welded to patch it up if it does not have to last long.

[tuftythesquirrel]

22 hours ago, Redbeard said:

What do you mean by a 'regular boiler'? You refer to a difference between a 'regular boiler' and a system boiler, so I think by 'regular' you must mean a combi (instant HW; no cylinder). 

 

@Redbeard I believe that a regular boiler is also referred to as a heat only boiler, so I don't think is a combi and would need a hot water tank of some description.

[ProDave]

16 minutes ago, tuftythesquirrel said:

 

@Redbeard I believe that a regular boiler is also referred to as a heat only boiler, so I don't think is a combi and would need a hot water tank of some description.

Which is referred to as a system boiler, but you made a diferentiation between a system boiler and regular boiler, which is what we don't understand. 

[Radian]

2 minutes ago, ProDave said:

Which is referred to as a system boiler, but you made a diferentiation between a system boiler and regular boiler, which is what we don't understand. 

System boiler means unvented whereas regular (heat only) means vented which is what they have now.

 

On 05/12/2022 at 13:30, Goodremy said:

Our current cylinder is very old

So does the higher price for the system boiler include the unvented cylinder that you need to have to go with it?

 

 

Edited December 6, 2022 by Radian

[MJNewton]

21 minutes ago, Radian said:

24 minutes ago, ProDave said:

Which is referred to as a system boiler, but you made a diferentiation between a system boiler and regular boiler, which is what we don't understand. 

System boiler means unvented whereas regular (heat only) means vented which is what they have now.

 

Not necessarilly. We've hot a heat-only boiler with an unvented cylinder and CH system.

 

A heat-only boiler - as the name implies - just provides heat and so you need external components (pump at a minimum but also valves if more than one circuit) to incorporate it into the wider system. In addition to gas and (if a condensing boiler) condensate drain, it has a single a flow and return.

 

A system boiler has the pump built-in and separate flow and returns for CH and HW.

 

Vented vs unvented is an orthogonal issue not tied to heat-only vs system boiler type, but specific boilers may be designed to only work with one or the other.

Edited December 6, 2022 by MJNewton

[Radian]

1 minute ago, MJNewton said:

No necessarilly.

Quite right, but that was my take on the OP's particular situation. I should have phrased it differently. Indeed my own boiler is heat-only but it says it's suitable for use in both vented and unvented systems.

[SimonD]

My first question is why not get a replacement casing? Has the person condeming the boiler checked availability and pricing as an option?

 

On 05/12/2022 at 14:57, ProDave said:

Is it really a serious fault (gas or combustion products leaking) or just an outer case?

 

On most boilers nowadays (at least 15-20 years) the casing is classed as part of the flue system and if there's a hole it means the boiler ain't room sealed any more, thus dangerous.

 

2 hours ago, Radian said:

Indeed my own boiler is heat-only but it says it's suitable for use in both vented and unvented systems.

 

I think there's generally some confusion about boilers types and systems here. Perhaps it's easier to think of the boiler as just the heat source and then separate the systems that use the heat. One system is the central heating, the other is domestic hot water and with domestic hot water there are two sides to the system - the heat input and the heat output.

 

Both system and heat only boilers heat a defined body of water contained within a set of pipes that provide the heat input to the radiators and hot water cylinder. This heat input circuit can either be open vented or sealed. A heat only boiler is usually found on an open-vented system, but, using an external expansion vessel, can be sealed under some circumstances if deemed okay by the manufacturer. A system boiler is sealed as the system boiler has a built in expansion chamber. This circuit of water is, through diverter valves pump through either the hot water cylinder or the heat circuit, or both. The difference between the boiler types is due to what is included in the boiler and as correctly pointed out above a system boiler has pump and expansion valve, some have the automatic bypass fitted and so forth, so there's less additional stuff needed. With heat only you need to install a pump and bypass etc. separately.

 

You then have the heat output of the hot water cylinder. On either of these boilers, there can be an unvented cylinder, which simply refers to the fact that the hot water is stored within the cylinder under mains pressure and is not vented to a F & E tank in the loft. This has no effect on the heating circuit of the boiler as it's kept entirely separate by using an 'indirect' cylinder.

 

So overall, either/both the systems can be open-vented or unvented so it's important to differentiate between which particular side of the system is being referred to.

 

On 05/12/2022 at 13:30, Goodremy said:

If we got the system boiler now, all pipework will need upgrading including the external mains. On the other hand a new regular boiler would use the current setup but we'll be using it for only a short time until we renovate.

 

Not necessarily. The external mains upgrade is required for the unvented cylinder to work as designed. You could actually install a system boiler and just remove the heating F & E and at the same time retain the gravity fed open vented hot water cylinder until you have the work done. Your minor risk with this is that the pressure within the heating system of the new system boiler might cause leaks in the old system - but I think that risk is probably fairly minor.

 

[Goodremy]

On 05/12/2022 at 14:57, ProDave said:

This sounds like a case of "it wasn't broke why did you mess with it"

 

What part of the casing?  Is it really a serious fault (gas or combustion products leaking) or just an outer case?

 

I would seriously look at getting it welded to patch it up if it does not have to last long.

Thanks everyone for replying to the post. I have been busy chasing quotes the whole day.

This condemned boiler, here's the story: so, we have had British gas (BG)Homecare contract for over 4 years which includes among other things, central heating and boiler service. On 2/11/22, the BG engineer came to service the boiler which was working perfectly ( 22 rads, loads of hot water). About 3 mins into the service, he called out alarmed, asking if the boiler had ever been serviced. I was confused. I told him it's been serviced annually by BG! He showed me a hole in the casing and pointed to a horrible looking yellowish crusty weepy joint on top of the boiler; apparently it had been leaking over a long time and it had caused corrosion on the case. On close examination, the whole area behind the flue is rusted. This is a room sealed boiler and so it's an integral part of the boiler. The leaky joint is clearly visible when the front cover is off - it appears prior BG engineers couldn't be bothered to fix it while certifying the boiler as safe. Might I add that the carbon monoxide alarm present has never detected any gases. British gas denied responsibility for negligence and say that the boiler was old anyway but as a Matter of "goodwill" they've offered to refund 2 years worth of boiler service fees we paid and also one central heating cover totalling - which is still somewhere in the post.

Now we've got about 5 local plumbers in but all of them say it's unsafe and only quote for a new boiler. 

I think we are now tending towards a system boiler as the hot water was so slow to get to the tap and we have two showers with 2 pumps - like I said we have 2 separate plumbing systems (original house and extension. Well get it combined. We'll be renovating but with high prices we'll wait So perhaps in 2 years time. For now we'll upgrade the mains - we'd thought we'd do it with the renovation but it is what it is. 

[ProDave]

So it's had this leak for some time, but it has continued to work and has not set off the CO alarm.

 

If it were me, I would probably buy a new CO alarm, just in case the old one was faulty, and carry on using it.

 

Of course this is not advice.

[SimonD]

1 hour ago, Goodremy said:

He showed me a hole in the casing and pointed to a horrible looking yellowish crusty weepy joint on top of the boiler; apparently it had been leaking over a long time and it had caused corrosion on the case. On close examination, the whole area behind the flue is rusted.

 

1 hour ago, Goodremy said:

British gas denied responsibility for negligence

I would tell them that you're going to put in a call to Gas Safe and ask an inspector to come out and have a look.

[Goodremy]

Yeah, I'll try to that; the problem is they all say BG knows what it's doing. Here's a pic. 

 

Again it wasn't the gas pipe leaking; I think it's probably central heating water.

[Goodremy]

2 hours ago, ProDave said:

So it's had this leak for some time, but it has continued to work and has not set off the CO alarm.

 

If it were me, I would probably buy a new CO alarm, just in case the old one was faulty, and carry on using it.

 

Of course this is not advice.

Sorry it was leaking radiator water not gas. The liquid caused the corrosion. 

 

The CO detector works perfect; we regularly check it's functioning 

[PeterW]

2 hours ago, Goodremy said:

This condemned boiler, here's the story: so, we have had British gas (BG)Homecare contract for over 4 years which includes among other things, central heating and boiler service. On 2/11/22, the BG engineer came to service the boiler which was working perfectly ( 22 rads, loads of hot water). About 3 mins into the service, he called out alarmed, asking if the boiler had ever been serviced. I was confused. I told him it's been serviced annually by BG!

Standard BG sales ploy - sorry but save your money in future and get an independent to service it

 

2 hours ago, Goodremy said:

On close examination, the whole area behind the flue is rusted. This is a room sealed boiler and so it's an integral part of the boiler.

Thats bollocks - room sealed means the intake and exhaust are both from the outside air. Does it have a concentric flue or an old cage flue..? Most will happily run with no external casing so that needs properly checking. Are the indies also saying it’s not ok ..? Or are they just reading the BG condemned notice ..?

 

2 hours ago, Goodremy said:

think we are now tending towards a system boiler as the hot water was so slow to get to the tap and we have two showers with 2 pumps - like I said we have 2 separate plumbing systems (original house and extension.

 

This makes no sense - if you have to go system then you need an unvented or mains pressure tank to get better pressure. This isn’t that difficult .! You can put a system boiler on a standard tank but the pressure and flow will be lower.
 

[ProDave]

10 hours ago, Goodremy said:

Yeah, I'll try to that; the problem is they all say BG knows what it's doing. Here's a pic. 

 

Again it wasn't the gas pipe leaking; I think it's probably central heating water.

So that is the outer layer of the flue rusted.

 

Post a picture of the flue from the outside.  But usually the outside bit the air intake and the flue gasses are a separate pipe inside that.

 

If that is the case, that will also be running cold at the point it has rusted (run the boiler for half an hour, then get up there and see.)

 

Again not advice, but if it were me and I knew this was only short term, having confirmed it is the intake part of the flue that has corroded and confirmed it runs cold at that point, I would patch it up with car body filler for now.