Advice / opinions on electric combi boilers

[Lili]

Hello all
I hope it's okay to seek some advice on this forum.
A bit of background first: I live in a flat, built around 2000, originally came with PowerMax boiler, this was replaced with a combi Glow Worm end of 2012. End of 2015 had a leak from the flue, it was decided that it was due to poor installation, not following manufacturers specs re: flue drop (the boiler is quite far from outside wall, the total length of flue is close to 5m so the drop needed to be quite significant). What seemed to be a serious company replaced the flue, dropped the boiler so that the flue drop was maintained as per specs. Happy days.

Except yesterday boiler packed up (won't ignite), and engineer who just visited said it was due to combustion from the flue going back into boiler. He said it's a problem waiting to happen again, even if the flue is re-done again.
He recommended replacing it with electric combi boiler Elnur. I have to say that I am seriously considering going electric - even though I know running costs will go up. However, the flat is not big, it keeps heat well (we only really need to turn on heating when it's really cold, for about an hour or two in the morning and evening). As long as I don't have to keep a tank of hot water for washing etc., I think it won't be too bad. Just to note, we do like our baths (rarely shower).
Elnur is a brand I've never heard of, and I am a bit worried about going with them - what if another 2-3 years time the boiler breaks down, by then the manufacturer went bust, no replacement parts... I'll be back to square one, having to replace the boiler - AGAIN.
My other concerns / requirements:
- I really, really would love to avoid tank + electric heater combo, due to 2 reasons, one is space (very precious in this tiny apartment), and two, I've gone through this in one of apartments before and the running costs were astronomical - I hope a combi would not be so bad.
- I want to be able to forget I have a boiler for at least next 5 years. If I have to fix or replace a boiler AGAIN I think I'll just go mad (this is a third time in this apartment, and twice before in rented - all in a space of 10 years!)

Any recommendations re: other electric boilers that do not require a massive tank / don't take much space, are reliable, and don't cost a little fortune to run? Any things I should be aware of in terms of how hot the water can get, how electric affects water pressure or anything else?
Any other options I have?

Thanks a lot
Liliana

 

[Littlespark]

I put an electric boiler into a property I have that I rent out. It was to replace a wood burning stove that had seen better days. The reason I chose electric was 4 things...
1. No mains gas, I would have to have an outside tank or cylinders.
2. It's one less legislation for me to handle as I rent it out.
3. I didn't want to drill a hole through 2 feet of stone to put in the flue
4. I'm an electrician. I installed it myself.

The boiler is in fact just a water tank. There are 3 immersions heaters that heat the water in the tank using off-peak electric overnight. This tankful of water is used to heat the radiators when its needed.
The hot water is heated as it passes through a coil inside this tank.

Spacewise, it fits in the same space as the hot water tank I took out.

cons:
You need to get an E7 or other off peak meter put in.
The property is only a 2 bedroom with a bath. Any bigger, I don't think it would handle the demand.
I don't know how economical it is, as i'm not personally using it, but I would guess gas is cheaper running costs.
The boiler is made by MacDonald Engineers in Scotland, a well known copper tank manufacturer. The control panel that comes with it isn't very easy to understand.



Is it possible to extend the pipes and relocate a new boiler closer to an outside wall?

Pay the money and get British Gas to install a Worcester. Take out their maintenance contract, and they'll fix it for free under contract.

 

[Gasmk1]

all electric boilers will have a hot water cylinder as they cant work like combis.

 

[ShaunCorbs]

I put an electric boiler into a property I have that I rent out. It was to replace a wood burning stove that had seen better days. The reason I chose electric was 4 things...
1. No mains gas, I would have to have an outside tank or cylinders.
2. It's one less legislation for me to handle as I rent it out.
3. I didn't want to drill a hole through 2 feet of stone to put in the flue
4. I'm an electrician. I installed it myself.

The boiler is in fact just a water tank. There are 3 immersions heaters that heat the water in the tank using off-peak electric overnight. This tankful of water is used to heat the radiators when its needed.
The hot water is heated as it passes through a coil inside this tank.

Spacewise, it fits in the same space as the hot water tank I took out.

cons:
You need to get an E7 or other off peak meter put in.
The property is only a 2 bedroom with a bath. Any bigger, I don't think it would handle the demand.
I don't know how economical it is, as i'm not personally using it, but I would guess gas is cheaper running costs.
The boiler is made by MacDonald Engineers in Scotland, a well known copper tank manufacturer. The control panel that comes with it isn't very easy to understand.



Is it possible to extend the pipes and relocate a new boiler closer to an outside wall?

Pay the money and get British Gas to install a Worcester. Take out their maintenance contract, and they'll fix it for free under contract.

Or a much better idea get a local gas safe engy to do the work instead of bg

 

[Lili]

@Littlespark Take it to outside wall not really an option - it would fall within our bedroom (noise),+ awful lot of piping (gas and water) to go through bedroom and bathroom. That was the reason why it was done with that really long flue to begin with. With the different tarifs, not sure that will be an option - I've set a new fixed-price contract with EDF not long ago, so no idea if I'll be able to switch / how costly would it be. The biggest con for me in any case is space... I'd have to see how much space it would take, but the one I've had in that rented place was absolutely massive, and it was just a 2 bed flat (mine is 1bed).

@Gasmk1 Well, that was my understanding so far too, but according to this guy now there are a few electric boilers that work like gas combi - i.e. no tanks. I was wondering if any members here have any experience with them.

 

[Lili]

@ShaunCorbs TBH, I don't think gas is an option anymore, even though I'd love it to be the case. Even last time when I was fixing that botched installation I had problems finding someone who would take this on (a lot of engineers said - put in electric, now I wish I listened!). According to all my knowledge, it was installed as well as it could be - yet still broke down 2 years later. I'm not really keen to spend another pile of money, only to have another 2 weeks with no hot water 2 years down the line...
The only real question here is: can I/ should I go with that electric combi, or am I asking for trouble doing this, and should stick to tank+heaters, even though it basically eliminates any storage space I have :/

 

[ShaunCorbs]

Any chance you could take a pic of your fuse board ?

 

[Lili]

Sure, let me know if that helps.

 

[ShaunCorbs]

Spot on

Problem is with electric combis they need either a 10 or 16mm service so you need to get from your fuse board to the location with a wire as wide as 2 big fingers

 

[Lili]

@ShaunCorbs Not sure I understand. Do you mean my electric supply would not be capable of dealing with an electric combi, or simply that a big cable will need to be laid there between the two? If just the latter, that shouldn't (I think?) be a problem, as the fuse board is probably not even a meter away from where my current boiler is (and where, I hope, the new one would be). It's in a cupboard - so I don't really care how it looks. So if it's just a matter of putting an extra cable, I think that's fine. If it's more problematic - can you please explain?

 

[ShaunCorbs]

Wire would need to be installed if your happy could go in trunking

 

[SimonG]

all electric boilers will have a hot water cylinder as they cant work like combis.

Not correct with the Elnur. No cylinder in that one. Fitted one about 4 or 5 years ago. Expensive to run but does the job rather well.

 

[Chalked]

I would recommend you buy a new gas boiler and try to relocate it.
Electric combination boilers are not cheap! They are usually fitted where it's near impossible to get gas to the property.

And for the running costs. Expect to pay double.
Far cheaper in the Long run to stick with gas.

 

[Lili]

@SimonG Could you tell me more about this installation? When you say "expensive to run", do you have some numbers on what the gas kWh usage was before the switch and what the electricity usage is (not really asking cost as this will depend hugely on tariffs). What kind of property was that in?

@Chalked I went through all these options last time when it broke. Unfortunately my flat has only a single externally facing wall, and that is my bedroom or living room. Living room has a huge balcony window and little space apart from that, plus dragging the gas/water pipes there would be at least 10-15 meters long (it's exactly opposite side and across from the boiler room). And for my bedroom, as said, don't fancy the noise of the boiler where I sleep, not to mention it would look horrendous, with all the pipes having to be dragged to it from the opposite side of the flat. There was a reason why all engineers visiting so far considered that long flue run or electric the only feasible options. Pains me and sucks but that's the sad thing about this flat's layout I guess it's what you call "near impossible to get gas" - at least with current type of boilers where flue needs to be short.
As for "cheaper to run gas in the long run" argument - I've had it with myself when I first installed this boiler as a replacement. What I had to spend so far in installing and then fixing it (and it's still not finished!) would probably get me running on electricity for 10 years - perhaps at some point it's time to cut the losses...

 

[SimonG]

@Lili
The installation was in a 3 bed 1 bathroom cottage. Replaced an old oil boiler and rotten steel tank.
Installed in what was the old airing cupboard. No different to a gas combi. Ran off a 10mm electric cable and the boiler can be set to a specified kw rating in groups of 3kw. As for running costs I have no idea. Customer sold house 18 months after install. Been back once to replace an automatic air vent. House been sold again since.

The internal filling loop didn't meet wras water regs as there was no double check valve.

 

[Littlespark]

As others have said you'll need a 10 or 16mm cable run from consumer unit to an electric boiler via an isolator. 32 or 40A mcb added in the C.U to power the boiler, depends on power rating of the boiler. An installer will advise you on that.

The C.U itself is currently in a potentially dangerous state. You need to clip a shield over the gap between the RCD mainswitch and the smoke detector MCB. They're pretty standard size and shape, and easy to buy from local hardware or Homebase/B&Q whatever. Just TURN THE POWER OFF before you put your fingers anywhere near that gap!!
It would fail an electrical inspection with that gap.

 

[DevsAd]

Hi Lili.

I'm confused by some - well, a lot - of what you've said in your first post.

The GlowWorm was installed in 2012 (so it's only 5 years old) and it initially went faulty - due to an incorrect installation - in 2015?

Why wasn't the original installer taken to task about this? You had a 'leak from the flue'? What, combustion gases? And the installer wasn't made aware of their error?

At, I'm sure, significant additional cost you had the incorrect installation rectified by someone else which involved lowering the boiler in order to achieve the correct 'fall' in the flue? This was in 2015, and initially worked - as it surely should have. I mean, they presumably made the install follow the required guidelines, so it should have worked; either that length of flue run is 'ok' in which case it should continue to work, or else that length of flue run is excessive, always has been, should never have been entertained in the first place, and has never conformed to the manufacturer's installation instructions. In which case it should never have been done.

Either way, you are a 'layman' here, and you paid for a working boiler installation which you do not have, through no fault of yours. I do not understand why you are still having to fork out considerable sums of money in order to sort out other people's problems.

That's one issue!

The other issue is, how on earth is exhaust gas getting back in to the boiler air inlet to cause this current fault? Surely it cannot be a leak within the twin-walled flue run? If it is, then that's again down to either faulty components or a faulty install. Ergo, nothing to do with you, and not for you to pay to fix.

The only other way I can see this problem happening is if the external flue terminal is not ejecting the combustion gases far enough away from the surrounding air inlet (possibly down to too much flow friction due to the length of flue run), so some of it's being drawn back in via the surrounding air inlet? If so, surely an adaptation of a plume kit - ie extending the exhaust pipe further out/up so that the gases are blown nicely away from the inlet, would be a solution?

Or am I missing something?

 

[Lili]

@DevsAd - that's correct. Installed in 2012, leak was detected during British Gas annual check (part of cover) in 2015, they switched off boiler and left saying flue isn't covered. What exactly was leaking I'm not sure, but it was leaving rust around the flue joints (long run, so it wasn't one long pipe). Original installer by then disappeared from the market (company dissolved, not answering emails or phone calls) so I had to find someone else. Funnily enough, even though I went for what seemed like a more reputable company (quite a few employees, proper website, calling system and what not), according to companies house records they literally just filled for being dissolved in October, and I cannot reach them on any of the phone numbers (all disconnected). I honestly don't know what I can do to reach them to try and make them sort this mess out.

As you say, I am not a gas engineer, I explained to myself that the fact that it is such a long run, and thus is composed of multiple flue parts, makes it leak. The boiler in question is GlowWorm ultracom2 cxi30. I did check in the manual. The length of the flue is not longer than allowed - but it is quite close to the limit. You might be onto something with the exhaust not going far enough - also, we live in a very windy area so it's possible that the combustion gases are literally blown back in. But it's something I'd expect from the people doing in 2015 to know and do if required, given they were fixing exactly this problem.

As to your other point, it is *extremely* frustrating to have to keep paying for what is not my fault and should have been done correctly to begin with. Seems I am unlucky with going for people who disappear before the thing breaks. And no, not because I go for cheapest - in fact the company that did it in 2015 was significantly more expensive than some other quotes, but I thought I was going for quality and stability. Ha-ha... I would have gone with British Gas or similar but they only like easy jobs and simply refuse to even look at such an installation. They'd be happy to install a boiler if all the pipes were ready there for them, and the boiler hung on external wall - which is not an option in this apartment. Anything more complicated and they wash their hands.

In any case, I'm so sick and tired of this happening, and being with no hot water and heating for weeks, and as you say, forking out money for what is not my fault, I just want to get it done and forget about it. I can't go with a company that I'm sure will be there in another 2-3 years time to sort it out if it breaks, so it would be going with "one-man-shop" again which I simply can't face doing again. If that means electricity and higher ongoing bills then be it, I'm sure it will still be cheaper than paying a little fortune for fixing the flue.

 

[DevsAd]

What a nightmare :-(

You have confirmed yourself that the flue run isn't excessive, so I'm still flummoxed as to why the issue "is a problem waiting to happen" even if the flue were redone.

I just don;t get that - it doesn't make sense to me.

It doesn't matter how many joints there are in a flue, provided - of course - each is done up correctly and the flue is supported as required (and the max length isn't exceeded).

If it is done properly, then it should work. There should be no issues. And if it works when installed, then it should continue to work - nothing should change!

It shouldn't rust - it's made from aluminium and plastic.

I don't get it.

I would love to know how these exhaust gases are getting back in to the boiler intake to cause this problem.

Personally I would look for another opinion - a local company who has been around for a few years, and hopefully has decent reviews. You shouldn't be short of recommendations.

What is the access to your flue like - how much disruption would it cause to redo?

 

[ShaunCorbs]

Not all dev some are metal

Also probably a flue seal had gone and started leaking condense liquid

 

[Lili]

@DevsAd Well, at least this time I was smarter and asked them do it in a screw-on boxing so theoretically it should be possible to take boxing off, and put in a new flue. But I'm really worried there is something wicked in the layout of this flat that makes it impossible to do it well. There are some pipes going down between boiler room and bathroom that somewhat limit the position of the flue (it didn't seem like it was in the way but... who knows). I really tried to check everything (according to my very limited layman's knowledge, of course) - so I double checked their drop calculations, and I know they installed quite a few support points. Whilst the first guy cut corners, with these guys I had a feeling they really tried to make it right.

The company that came today to give me quote for electric said they could do a new gas installation (well, technically they said they could fix the flue on this one, but then it would only be 1 year warranty, which, if it breaks at speed so far, will not be long enough to see if it's done well).
Is it possible that the problem was caused by a boiler that was not good enough for this length of flue (despite what manufacturer says)? Could replacing it with a new one potentially make it better, or is it just them trying to make more money? In any case, with all the leaks that were happening I suspect this boiler might be on its last legs anyway...
I'm really torn. I would much, much rather stay on gas for obvious reasons but I'm really scared I'll face this issue again (and even if this time they paid for fixing, that does not compensate for being weeks without hot water/heating!)...
Sigh.

 

[Chalked]

Which boiler ar they recommending?

 

[Lili]

@Chalked Vaillant. Not sure which model yet, I'm supposed to get the quote tomorrow.

 

[Lili]

Since you people here are so very helpful (thank you!) can you take a look here and tell me if that looks like a good job, and if so - why would it leak? Or if not - what's the problem? (The marks on top of the boiler are from previous leak, that one was evidently wrong in a number of ways...)

 

[ShaunCorbs]

not bad, cant tell the fall but looks close

vaillants like to eat flue seals or rain waters getting in

whys the case of the boiler off?