Replacement boiler - financial options and general advice?

Bendy_House

Onto today's quote:

• Completely different direction again - he suggested he could do a like-for-like replacement and leave the open-vented system.
  
  
• Fully recommended a Combi boiler with a Powerflush. When questioned about getting a sealed setup, he said "Sealed system is a Combi system" - eh? Ah! A smartassed twit? Cool. Yes, combis are 'sealed' systems, and so are system boilers. So what's his point? None.
  
  
• Reason for Powerflush - "Build up of sludge would likely void the boiler warranty and mean we pay for boiler repairs as it would be down to system" - makes sense! Yes. Combi boilers, in particular, are susceptible to being sludged up as they have much finer water channels within them - I should know... But even a normal boiler ain't going to thank you for sludge. Most installation instructions say that the system must be cleaned to a certain BS standard, and leave that up to the installer; they don't INSIST on a PF. BUT, you can bet your bottom dollar that if your boiler goes faulty after a few years and 'sludge' can be shown to be the issue, they won't cover it with their warranty - and rightly so, as it isn't a 'boiler' fault.
  
  
• Reason for suggesting a Combi boiler - "20+ components left in the system could go wrong, so changing everything would give peace of mind". "We've had customers where they've done this and then had to replace parts for £250.00 or so". Hmm, I smell BS. Yes, a combi boiler will contain inside it all the extra bits you currently see out in front of you - diverter valves, pumps, frost stats, thingies and whatsits. But that just makes these parts smaller, more costly to replace, and more susceptible to going wrong. So his 'argument' is moot. Combis are known to be less reliable, simply because they contain more moving parts inside.
  
  
• 7-year warranty Cool.
  
  
• Gas run from meter - keen to keep it neat as possible (additional work and materials) but was open to the idea of running it on the surface (I mainly suggested this to save money), especially when he suggested that a length of copper pipe is £15-20.00 at the moment. A change to a combi will REQUIRE a new gas pipe, as combis consume a lot of gas when heating water instantly. A system/heat-only boiler will likely NOT need the gas pipe replaced.
  
  
• Quote will be provided for a like-for-like and a Combi setup. Good, both options.
  
  
• Pointed out that a full test hadn't been carried out by the test engineer for the annual service (we'll question this with Your Repair)
  
  
• Very much a "rip it all out and start again" approach. Didn't seem overly keen on the like-for-like or sealed system ("half-way house") More BS. He seems fixated on combis. A system boiler isn't half-way in any sense; it sounds more like he's a half-wit.
  
  
• General thought about current setup is that we're wasting money heating up the water in the cylinder, only to use a small percentage of it, whereas Combi would only fire up as needed and be on-demand. This is true, but if your hot tank is well insulated, it should lose that much heat. I guess it depends on how much hot water you use - if it really is small, then a combi 'might' make sense, but for most folk the added extra cost of a combi isn't justified. You could always replace your hot cylinder with a smaller capacity one! But I wouldn't bother. Just make sure it's well insulated.
  
  
• Ballpark figures (detailed quote to come) - £2,300 + VAT for like-for-like, plus £500.00 for Powerflush on top. Combi setup would be in the region of £4,500.00 but apparently we'd make our money back in no time? Only if you live on planet Zorg. The savings will likely be marginal, and the extra outlay more than £2k. It will take years to potentially break even, by which time the combi will likely be developing costly faults. Treat his comment there with extreme caution...
  
  
• RF-based thermostat would replace our current thermostat to allow us to be portable (seems a little pointless?). Current thermostat would be disconnected and removed. If it ain't broke, don't whatsit. If you are happy enough with a manual room stat, then there's no need to change it. Having said that, a Prog Stat really is a good idea for most folk. But, if you are fully on the case - fingers always ready to twiddle the knob as required - you are effectively a Prog Stat... :-)
  
  
• As the thermostat would no longer be fixed, TRVs would be fitted in all rooms except the bathroom (as per the first quote we received). Whatevs. But, if the 'stat is fixed, then that room shouldn't have a TRV. In reality, you can make any TRV a non-TRV valve simply by opening it up fully to '5'. Jobbie jobbed. Personally, I would have the 'stat in the room where you spend most time, provided that room doesn't have a secondary form of heating such as a fire/stove.
  
  
• Didn't ask to see soil stack or even explain where the condense pipe would go? As he was so focused on the Combi setup maybe a condense pipe isn't needed in that case? Yes, it is. So he's a lackadaisical twit. He overlooked this pretty important point.
  
  
• Generally very pushy and sales-driven approach which I sensed as soon as he disregarded what I asked about and didn't give much time at all for questions. About what we expected as this is the first larger company we've had to do a quote (there are only 2 purely for the reason of giving a balance but not too many as we've been here before with other trades). He wants to sell you a combi - end of. And, looking at the quote, I think I can sense why...
  
  
• His general attitude also seemed to be "this isn't very good is it, we could sort that out for you". Even commenting on how sellotape had been used on one of the flue connections (presumably from when it was first installed - I hadn't noticed it until he pointed it out) Ooh, spotted some sellotape? But not a route for the cond. (I bet that sellotape had nothing to do with the actual integrity of the flue in any case, but was just part of the original packaging.)
  

Thoughts - does any of what he said make sense?

BUFF

Bendy_House said:

• RF-based thermostat would replace our current thermostat to allow us to be portable (seems a little pointless?). Current thermostat would be disconnected and removed. If it ain't broke, don't whatsit. If you are happy enough with a manual room stat, then there's no need to change it. Having said that, a Prog Stat really is a good idea for most folk. But, if you are fully on the case - fingers always ready to twiddle the knob as required - you are effectively a Prog Stat... :-)
  

On the whole I agree with the general gist of what B_H says. Today's guy want to sell you the most profitable/least effort system for him.
If you were starting from scratch then a combi would probably make sense. But you aren't starting from scratch so a combi adds extra cost for you by having to remove existing & repipe etc.
If you want a stronger shower (usually less head to the outlet than a bath & more restrictions) then a combi or unvented dhw tank can make sense.

The one area that I would differ in slightly from B_H is controls. I am a firm believer in the ability of advanced (load and weather compensating) controls, used properly, to save you gas consumption & therefore also money - they will pay for themselves over the typical lifespan of a boiler. They can also give your system an easier life & therefore a more reliable/extended life.
You can do most of what they do manually but it's just simpler/more efficient to have them & let them do their thing. Minimum that you want is a programmer & room stat. (ideally that can let you set different temps. for different times of day/night) plus your TRVs.

RF controls are convenient if you do regularly move between rooms or again if you were starting from scratch & didn't want to chase walls for a cable. But you aren't starting from scratch plus you have to watch out that they will give a reliable connection over the distance used - walls etc. inbetween can cause issues.

You also might want to ask your installers about flow & return temperatures (from 15 June 2022 under part L they will be mandated  on new installs to 55C or lower flow temp - yours as an existing/replacement install can escape this but it's probably a good thing to aim for). The lower flow temp means that the boiler will condense more of the time, give your system an easier life etc. - it does mean that some/all of your existing radiators may be undersized for output at those temps though.
Again, good controls will help ameliorate this as if that's the case they'll either run the system hotter to start with then drop flow temps down one they can or they will bring the boiler on earlier at the lower flow temps to reach the required temp at the required time (this is sometimes called optimum start).

Bendy_House

Wow, a 55oC FLOW temp is going to be mandated? I guess it does make sense right enough, and should be fully achievable in a modern build.

Good point about weather-compensation, which none of the installers has seemingly mentioned, and never occurred to me. In the OP's case, this could be the easiest addition ever, as the loft is practically 'outside'! It would almost certainly enable that very efficient low flow temp at least for a good part of the year when it's chilly/cold, but not freezing.

Do all current boilers have the ability for this feature built in? If so, all it needs is what should be a cheap temp sensor added in a suitable place. OP, this would automatically turn the boiler's flow temp down when the weather isn't cold enough to justify 'piping hot' rads, so the boiler will be running as efficiently as possible when it can. It'll be noticed by the rads being 'cooler' than usual, and probably running for longer like that, instead of going 'hot' and then shutting off for periods.

On a system/heat-only boiler, I presume it would know to do this for CH, and not DHW?

BUFF

Tbh I don't know if heat only boilers have the modulating abilities of a modern combi (I would imagine that all combis available for sale in the UK will have the ability under Boiler Plus). Best to check with the individual manufacturers.
n.b. some boiler manufacturers e.g. Vaillant, Viessmann & Worcester have proprietary control buses which means that whilst they will work with 3rd party manufacturers controls they may only achieve maximum efficiency with their own-branded controls (we are only perhaps talking an extra few % efficiency though). Others may use a cross-platform bus known as OpenTherm which was designed in principle to allow cross manufacturer use (but even then apparently some manufacturers use flexibility in the OpenTherm spec. to include manufacturer-only features) 

Some controls don't need an external sensor for weather compensation but can use weather information from the internet  - this does have the advantage in that it can predict ahead & act accordingly but it also means that if you are in a different microclimate than your local weather station it may not be quite the right information for your house.

Again, I don't know as I haven't needed to look into it as I have had a combi for ~30 years - check with manufacturer.

Shoxt3r

Thanks again all for the replies.

The quotes have been coming in thick and fast over the Bank Holiday weekend, including 1 quote which was only talked about on Thursday.

Suffice to say, the company recommending a combi boiler setup has come out as one of the most expensive. 

Standard boiler setup
Boiler Installation swap
Remove existing boiler
Supply and install:
Alpha heat only 15kw boiler
Vertical flue
Lead flashing kit
1 x addy system filter
1 x programmer and stat

Test and commission
£2,450.00 + Powerflush (highly recommended option) at £580.00 = £3,636.00 inc. VAT

Combi setup
Boiler Installation swap
Option 1
Boiler conversion from gravity to combi
Remove existing boiler and any unused pipework
Supply and install:
Alpha Evoke 33kw with 7 year warranty
Vertical flue
Lead flashing kit
3 amp fuse spare with back box
Climatic RF controls
Shock arrestor and tee
Scale reducer
Adey system filter
28mm slotted meter union
Condensate neutraliser

Install new gas run
Test and commission
£3,190.00 + Powerflush (highly recommended option) at £580.00 = £4,524.00 inc. VAT

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Following on from this visit we then had two additional options on Thursday & Friday, both of which recommended a like-for-like replacement with a heat-only boiler. Both were recommending Baxi brand (one also does many others including Ideal and Worcester) as well as a Powerflush.

However, only one of these recommended a change of the gas run to "bring it up to standard". Funnily enough, one of them used to live a few doors up and so knew the pipework and general layout very well and said that we should not look into any other boiler setup due to the age of the system/pipework.

We've only had a quote from one of them which was pretty detailed but by far was the most expensive (bearing in mind it doesn't include a gas run replacement) - £3689.00 + Powerflush at £350.00, both plus VAT = £4039.00 (£4846.80 inc. VAT)

Both of them did say that we would need scaffolding to safely swap the flue because of the narrow frontage we have at the house and this has been included in the cost (waiting on a quote from the second visitor).

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In addition to this, the "risk-averse" guy has come back with a quote, despite a couple of phone calls related to the safety of the work (again, discussed scaffolding but also how we feel about slate roof tiles being damaged whether a roof ladder or scaffolding is used, to which I said "well we'd rather you didn't damage our roof!").

However, he has come in by far the lowest quote so far:

"I was looking for what I believe to the best value boiler for you that has a stainless steel heat exchanger and the longest warranty. I was a little adrift regarding warranty on baxi boilers. It’s only there system boiler you get a longer  warranty and their regular boiler doesn’t have a stainless heat exchanger. So what I come up with is an Alpha  E Tec 15R . This has an 8 year warranty along with a stainless heat exchanger. Using this boiler and all associated components, magnacleanse the system and using a scaffold to access the roof I can do for £2,570.00."

Just over £2.5k seems ridiculously cheap for a job of this size, particularly as he's not going to do a Powerflush of the system, and admits he could also damage our tiles while doing the work...

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Lastly, we've gone back to one of the original quoters (the one which said he couldn't source Baxi or Worcester due to supply issues) and asked him to try again with the quote and include Powerflush, a like-for-like Ideal & Baxi boiler and whether we also need to consider scaffolding (his idea was that he'd swap it internally I believe).

I'm also looking into the annual service that took place as a number of installers have stated now that the service wasn't carried out properly and a pressure test should have been entirely possible without even touching the gas valves!

Bendy_House

Does your current boiler actually work? If so, why don't they carry out a gas pressure test on it? Yes, boilers can vary a bit, but one 15kW boiler should be consuming pretty much the same amount of gas as another. So, they take a static pressure test at the boiler's gas valve (just before the burner), check it's ok, then fire up the boiler to max. See how far the pressure drops. If it's still within spec, then the existing gas pipe should be fine. Am I missing something? Why is the gas pipe such an issue for these guys?

Anyhoo, you only fit a combi if you either WANT one or NEED one (eg to save space). Other than that, you should stick with what you have, provided it's working fine.

I'm personally not impressed by the reasoning for not changing the type of system - ie from vented to unvented. I understand it - they are worried about weaknesses in your system, rads or pipe joints which could be revealed by the larger pressure of a sealed system. And they might feel responsible for sorting this - tho' a disclaimer should cover that. 'Sealed' systems are just better all 'round. Fully isolated from the air. A limited, contained amount of water - so no endless floods if a pipe bursts. No ballvalves to stick and overflow, wasting water. A pressure gauge needle on the boiler to monitor the system's integrity.

It strikes me as tho' these plumbers are going, "S***! This is an old system! Ok, lads - gently does it... Like-for-like, check it's running fine, and then back off slowly before she blows..."

Bendy_House

Hard to say anything about the quotes, other than (a) I don't know of any way to fit a flue from the inside, other than they are possibly hoping they can simply push the new flue through the existing rubber collar, and leave it like that. That's a risk. And (b) any quote over £3k for a heat-only boiler swap just seems extortionate to me.