I'm just thinking about the cost etc of replacing our old wall hung Baxi boiler. No urgent requirement for it to be replace, and therefore no real plan - mainly just thinking about the sort of cost we may have to expect should we need to do this sometime.
Currently we have a balanced flue (boiler on external wall in kitchen) with feed/return and gas pipe coming down through the ceiling above (its a 3 bed
1930's semi).
What are the pros/cons of condensing boilers? Smelly flue gasses and mist, along with higher efficiency.
To be honest, I don't like the ideas of newer boilers (fanned flues etc) as all I seem to hear is "My PCB's blown again for the 3rd time, and at £150 to replace its expensive" or "The fan's gone". Please convince me that new boilers don't stop working after a few years, and have expensive maintenance. I just seem to think that an old boiler will last longer than a new boiler - and therefore I don't like them!
So - potentially could I purchase the boiler of my choice (and at my price!) and get a fitter to fit it? Or am I best specifying to the fitter the boiler I want, and getting him to get it with his discount?
Any recommendations for boilers (including condensing, but excluding combi's) and their approximate cost. Excluding the cost of the boiler itself, what sort of cost should I expect to have the boiler fitted.
Are there any issues with getting a boiler to work with the controls I already have? I've got an old Potterton EP2001 and a new Solwise programmable thermostat which I would very much like to keep (they do an excellent job for what I want from the heating).
Basically, the boiler is old and I want an idea of the sort of cost I should expect to replace it (boiler and installation), and a recommedation for some good (reliable and efficient) boilers.
The fumes don't smell. The mist can be a problem. If not then fine.
These people have tended to buy the troublesome boilers. Fan flues have been around for 30 years or more, and are virtually standard in all boilers over the past 20 years. There are Lada's and RRs of the boiler world too. On this forum you don't hear of the boilers that have gone along faultlessly for 10-15 years, only the problem boilers. The nature of the group.
Older boilrs had little inside them. The point is "new" boilers. "All" have pcbs inside.
Specify the boiler you are happy with. There are simple basic heating boilers around. The new Wickes light cast-iron boilers (Halstead) are simple, not modulating burners, but you still require pumps and zone valves outside of it.
Non-condensing:
- Heating boiler - Wickes light cast-iron (fanned flue & efficiency of around 78-79% ) £399 40,000 BTU/h. This is a basic "heating" boiler. 2 yr guarantee. Can be pressurised.
- System Boiler - The Vaillant Thermocompact RSF 615EH 22.3 - 51.200 Btu/h. Price £446.50 Including VAT. Efficiency of
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is a "system" boiler with built-in pressure vessel, pump, etc, with an efficiency of around 80%. 2 yr guarantee on this the last time I looked
Condensing:
- Fully modulating System Boiler - Keston Celsius (fully modulating with load compensation control) Expensive, but you get what you pay for. Many happy owners on this ng.
- Fully modulating System Boiler - The Baxi condensing boiler is not bad either.
- Fully modulating System Boiler - Any Vaillant, but expensive. So a few hindered quid over, is that such a big deal?
- Non modulating Heating Boilers - There is only the Ravenheat CSI Primary to my knowledge, there may be more. Can be pressurised or open vented. A direct swap for many boilers. There may be others. Malvern do a non-modulating condenser.
The Ideal condensers are having a bad time as they are having a lot of call backs in the 1st year with BG. BG has stopped specifying them, although still on their list. Those I have come across have been v good, so it may be they are doing something wrong with the installation.
Fully modulating condensing system boilers are the better option.
Well I think we've done that one to death in numerous posts. They certainly can make the cost savings suggested on the SEDBUK site. I am saving something between 25 and 30% of gas consumption, and have actually added about 10% of heat output to warm my workshop for part of the day.
Some types with premix burners (where the gas and air is mixed before the burner) do release a little unburnt gas when igniting, but this is seldom noticable. From the chemical perspective, the emissions of NOx gases are way down on older boilers. Other than that the output is water vapour. Depending on the boiler and operating conditions, a condensing boiler will give a plume of water vapour at the outlet. However, since they modulate down in output, most of the time this is not substantial and with a well designed product, most of the water vapour doesn't leave the boiler though the flue but is collected by the drain.
At the present time there is a minimum SEDBUK efficiency of 78% as a requirement for new boilers as part L1 of the Building Regulations.
There is a proposal (which you can find on the ODPM web site), to raise this limit to 86% from April 2005. This will effectively take all non-condensing boilers off the market unless there is some technology miracle, because the highest is currently 82%, whereas condensing technology achieves 90%+.
A lot of this depends on the individual product and manufacturer. For example, you will see Potterton regularly mentioned in dispatches with certain products having a poor reliability in this regard. However, keep in mind that some of the manufacturers like this have changed hands sometimes numerous times over the last few years and often the purchase has been for the brand name rather than the products. 20 years ago, Potterton had a good name for reliability, but this slipped more recently. Keep in mind also that some manufacturers have much larger installed bases than others for a variety of reasons. Inevitably you will read of more failures of these.
Like anything else you do get what you pay for. If your objective is to go for minimum initial outlay then you are not going to get the best quality or longevity. The famous quote of John Ruskin, the victorian philosopher certainly applies:
"It's unwise to pay too much, but it's worse to pay too little. When you pay too much you lose a little money - that is all. When you pay too little, you sometimes lose everything, because the thing you bought was incapable of of doing the thing it was bought to do.
The common law of business balance prohibits paying a little and getting a lot - it can't be done. If you deal with the lowest bidder, it is well to add something for the risk you run. And if you do that, you will have enough to pay for something better."
I generally adopt the latter philosophy because I would rather do something once and well and move on to the next thing rather than messing around.
You can buy a really cheap basic boiler, for £400 or so, but it is not going to be great; you can go for a good condensing product like a Keston, Vaillant or Ideal for £700-900, or a high end like a Micromat. I did the last of these and the cost is north of £1k, but it's as solidly engineered as a tank and came with a 5 yr parts and labour warranty.
Well you could buy yourself at a good price, but remember that the fitter wants, quite reasonably to make a margin. The discount that the fitter can get, or part of it will factor into it. You could try getting two quotes of supply and fit or fit only, but don't be surprised if the difference is not what you you think or if there is a lack of interest in fit only.
The fumes don't smell. In fact, the flue gases are much cleaner than a traditional boiler. The only difference is that the condensing boiler fumes are visible simply due to the water, whilst the traditional fumes stink because they are so environmentally dirty. There are far fewer nasties in condensing plumes.
20-30% greater efficiency pays for a lot of PCBs. Choose a decent make and you won't get these problems. Don't choose a make based on what cast iron dinosaurs the companies made in 1965. Modern condensing boilers are almost identical to other modern boilers in terms of complexity. The only differences are in the heat exchanger, condensate drainage and slightly more complicated internal programming.
Around 1200 +/- 200 quid for a reputable local installer (but may be difficult to find one able to do it). Around 2500 for BG or other national.
Worcester Bosch Greenstar 28HE System Keston Celcius 25
In any case, the boiler MUST have a downward firing burner onto a single heat exchanger. Anything less will give you grief.
Hmm, our old neighbours one smelled distinctively of gas (well, faintly of gas, but enough to notice), and when I read about it on here
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I just guessed it must have been a condensing one.
I guess I like the idea of something that's easy to diagnose myself when things go wrong, and I won't be fleeced by a Corgi taking a deep breath in and picking a large number out the air for fixing. With new boilers, lots of things I guess are computer controlled with more wizardry under the hood. But as you say, a new boiler is going to have this regardless.
Pumps and zone valves are already in place and working. If I could keep what I've got that would be great.
This is a "system" boiler with built-in pressure vessel, pump, etc, with an
Ahh, as I'd like to keep my existing pump etc (its working, why replace it, and its easy enough to replace myself if necessary) am I therefore restricting myself to not having a system boiler? Are there any modulating non-system boilers out there?
Modulating means that it'll change the BTU setting depending on the demand? Sounds a nice idea.
Thanks for the help - its certainly made me more aware of what's out there and what things mean.
Yes. The Ideal Icos might be ideal for you (excuse the pun). It is available without pump and will run on a feed/expansion tank. (I wouldn't recommend doing so, though, as sealed pressurised operation is better).
Hmm, what sort of work is needed to convert from feed/expansion to sealed pressurised? What sort of benefits can be gained? And why isn't it recommended?
Feed/expansion tanks have all sorts of problems associated. They pump over, give unlimited water leakage when a joint goes, introduce air into the system etc...
See the bottom of Ed Sirett's sig for more information.
Simple. Just remove the old pump and insert a piece of pipe. Connect up the system boiler to the old pipes in the same position. You will need to runs a 15mm cold water mains pipe to boiler for the filling loop. You need to run a plastic pipe from the boiler to a drain if it is a condensing model. The filling loop can be elsewhere on the system, but you must be able to see a pressure gauge when filling.
Remove the F&E tank and cap up the pipes. Better put an auto air-vent in the old open vent pipe, below the loft level
82% non-condensing? The CPSU Powermax has been discontinued and replaced by an a unvented cylinder version, now being termed a "combi".
The max non-condensing efficiency is the Radiant RMAS 21 E/3S combi at just under 81%.
This is rather academic as "peak" efficiencies may be 90-91 %. If a system is engineered to attain that as mating it to a thermals store, then SEDBUK is only a real rough guide. SEDBUK is being replaced by an EU method.
Some system boilers with integral pump have the pump under control of the electronics as well. Either it is three steps like an external pump or continuously over a range.
This is beneficial because the flow can be adjusted automatically as the heat load varies - e.g. as the TRVs operate and provides improved control and quieter operation.
There are a lot of benefits such as
- easier cleaning
- limited water escape if there's a leak.
- no opportunity for air to enter to corrode the system
- easier to eliminate air for bleeding.
Some boilers will work unpressurised but increasingly pressurised operation is mandated. Most boilers for sealed operation include the expansion vessel and controls either inside or as a kit. Ed's FAQ has more details......
Take a look at the SEDBUK database and select non-condensing boilers and you'll see what I mean. There's no point in arguing about 1% anyway because of the measurement statistical methods.
I guess that you are thinking of the older dual heat exchanger jobs?
Mine has a cylindrical heat exchanger like a drum with pipes inside around the edge and the burner being a mesh affair at the centre. In effect, the heat is exchanged radially from the burner at the centre.
Condensate happens around the periphery and runs to the drain sump.
The whole assembly is stainless steel, of course.
Viessmann uses a similar arrangement to MAN Heiztechnik of the Econox type burner in their Vitodens 200.
Well that sounds like a reasonable burner arrangement too. I was under the impression that some boilers used the burner underneath method, where, in a condenser, it gets a nice shower of acid.
Excellent website, in general, but I wonder about that remark of his about condensing boilers smelling: I understood they typically have much lower emissions than conventional types. I've certainly noticed smells from conventional boilers' flues.
However modern boiler manuals tend to have fairly comprehensive fault-finding guides. Some are even accurate :-)
And you can get (some boilers') manuals from their manufacturers' websites.
I think if there were an award for worst boiler ever it would have to be the Poxi- Batterton Barcelona condensing boiler. This would probably get awards in both the design and reliability classes.
Needless to say among the many a varied design flaws in the boiler is the updraft premix burner.
This means that I'm going to have to find a favourite condensing combi. I feel content with the Vaillant Ecomax products but they are seriously expensive at over £1k trade price. I guess the Ideal ICOS might be OK. Could try out the Glow Worm cxi range.
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