Hi,
Can anyone recommend a boiler that is suitable for fitting in a loft space? We (will) have 4 bedrooms and two bathrooms (both with baths and showers) so the boiler must handle that.
The only boilers I can find that have this capacity are not suitable for loft installation (e.g. Worcester Bosch Highflow 400). I am not convinced (yet) that a combi will be suitable.
TIA, M
A high flow combi will be suitable if you know its limitations. Would both baths be used at the same time? probably not. The Highflow can go in a loft., if you can get it up there.
Try a Potterton Powermax, floor mounted, they have a two bathroom 150 litre jobs. A one box solution. It breaks down for ease of handling, so easy to get into the loft.
Or you could fit two Worcester-Bosch Junior combi's up there. One doing one bathroom, one doing the other, one doing the utility room one doing the kitchen. One doing upstairs heating with a programmer/stat, one doing the down with another programmer/stat. Upstairs can be off when down is on saving on bills. Divide and rule, one shower will not affect the other provided the water supply is fine. If one is down you always have hot water and heating in the house.
Very cost effective, simple, effective and certainly worth considering.
Almost any modern boiler that you can squeeze through the loft hatch will be fine. The loft is a particularly good place for a modern condensing boiler as the plume is clearly not a nuisance going through the roof. Also, modern boilers tend to be lighter than their older cast iron counterparts.
Whether you go for combi or lots of different storage based solutions depends on your intended usage profile. However, with 2 proper bathrooms, a non-storage instantaneous combi would probably not be suitable. You should be looking for either a large storage based "combi" (which could be difficult to get into a loft), or a two box solution. In either case, you'll need to check external dimensions against your loft hatch before ordering.
Using a heat bank or unvented cylinder (rather than a gravity fed cylinder) would be advantageous, as you don't have to have a high up cold water cistern, or combination cylinder that may be prone to running out if two baths or showers are run simultaneously. It also allows a shower in the loft should you later convert.
Provided your mains water supply has a good flow rate, these solutions will provide excellent shower and bath performance. If fitting yourself, a heat bank will be simpler to fit. If fitting professionally, an unvented cylinder is more likely to be understood by the fitter. The advantages and disadvantages of each has been done to death in the past, as a quick google will show.
There are requirements for there to be a proper boarded floor, a fixed (but retractable if desired) loft ladder, guarding, electric light etc. These are all useful to have anyway, but must be budgeted for if not already present.
Christian.
kind of weight in the loft.
So that's four in total now. Do you have a special offer on them this week?
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It is?
Mmm.
I was thinking that Worcester-Bosch have "discovered" you and put you on commission, although one does have to say that some men are discovered and others are found out.....
.andy
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baths
suitable
Would both
I doubt both baths would be used at the same time very often. But I'm sure two showers or a hot tap and shower would be used simultaneously. I do like my bath to fill quickly.
I looked at the W-B web site and I am confused about the possibility of siting the Highflow in the loft. Although they do a balanced flue option they still state ventilation requirements to BS 5440:Part 2 (high and low vents).
too expensive for me. Again I am uncertain of the ventilation requirements for this boiler.
I also wonder about the boiler controls. I don't want to have to go in the loft every time I need to change the boiler settings. Do any boilers have full remote controls?
doing the
considering.
Interesting idea, but I guess two small boilers would cost more than one large. And the installation and servicing would be more costly.
M.
I put a WB Greenstar 28HE System up in my loft, along with a 180L DPS Pandora. The price of both boxes was about £1500 total, which might still be too high for you, but would easily handle two bathrooms. You could always put in a cheaper boiler to reduce the cost a bit, and can probably get a better price from DPS than I managed.
What do you mean by controls? I have my main programmer in the understairs cupboard, although it is always set to 24H on. I then have an S-Plan Plus setup with programmable thermostats in the master bedroom, lounge, kitchen and (when they get installed) conservatory and loft conversion. The only controls left on the boiler itself are the flow temp, which is set and forget.
Christian.
OK. It looks like a non-storage combi will probably not be suitable. I measured the flow rate of the existing hot water and it's 16.5 litres per minute. The only combi I can find that comes close to this is the W-B Greenstar 40 HE Plus which claims a 16L/min flow rate (but I guess the water would be colder than ours). The Vaillant AquaPlus is interesting. It claims to supply 170l in 10 minutes with a 15 litre storage vessel. I've no idea how it can achieve this.
We won't do a loft conversion because the roof hight makes it too low. I don't have the skills to fit heating systems myself, so am reliant on a plumber. All the plumbers I have contacted only want to fit combi boilers though.
I'm not sure how I can measure the flow rate of the mains. There's only two taps connected directly to the supply and their both small.
Is there a FAQ for the pros and cons of unvented cylinders?
Should be OK. I was going to do this anyway.
M.
Yes, the combi flow rate will be at delta 35 or so. Your old hot water system is probably on delta 55, so is equivalent to a combi flow rate of 26 litres per minute during winter. During summer, the difference would be less stark, as the storage system will work as before, whilst the combi will perform better.
Even combi fanatic could install a DPS Pandora. Explain that all it requires is cold mains in, hot mains out and standard S-Plan controls to the boiler. It is much simpler to fit than an old gravity based hot water system.
Measure from these anyway. If even the small taps can provide enough, then you're laughing. Less than 20 lpm, get worried. 20-30 lpm, OK. 30+, good.
40+, excellent. If you have a garden tap, try that, too.There must be somewhere, however, from the top of my head:
Heatbank:
Unvented cylinder:
Don't get bogged down by the differences, though. They are both excellent solutions.
Christian.
It is 37kW, which gives 15.1 litres/min @ 35C delta T. The 15 litres is stored at aprox 80C (a small thermal store I believe), so giving approx 20 litres at about 40-45C. 15.1 * 10 = 151 + 20 = 171. Near enough 170 litres in 10 mins. So it will fill a normal bath in about 5 mins.
It is a two stage flowrate combi, giving aprox 17 litres/min dropping to
15.1 litres/minThe AquaPlus has been available on the Continent for a few years, but new here. I believe it had to be amended to the UK market. Not cheap either.
One suggested a vented tank in the roof or a storage combi in the garage. However the garage may not be built until April next and I know the building regs are changing and the boiler we would fit would not be condensing.
BTW: Why are vented tanks so unpopular now?
No garden tap but I'll try to measure the flow rate from the two cold taps tonight. Incidently another plumber came around yesterday and said that our flow rate in unlikely to suit an unvented cylinder because we have a
1/2" main (he didn't look at it though, but he does know the area). I'm not doubting his word, but it has left me even more confused.Would a heat bank be inefficient if we only use hot water sporadically? i.e. very little is used during the day in the week, but loads in the evening? (I would have thought it would take a lot of energy to keep the heat bank up to temperature).
Why would an unvented cylinder give a higher flow rate? Aren't they both limited by the mains water flow?
M
The poor pressure is unsuited to modern hot water usage (showers) where pressure is more important than flow rate. Combi boilers, unvented cylinders and heat banks all use mains pressure, which is ideal.
In itself, it might not be a problem. The 1/2" section may be short. The static pressure may be very high, squeezing more water through a smaller pipe. Only a test will determine the suitability. Note that the storage mains solutions will still work on a low flow rate, you just don't get the full advantage until you rip out the old supply and put in some new 25mm MDPE.
Not significantly different from other storage solutions of the same energy capacity.
If they are mains flow rate limited then the heat bank may even have an advantage, as you don't have a PRV to squeeze through and the route is more direct. However, the heat bank will have a maximum transfer rate above which temperatures drop as the plate heat exchanger can't keep up. That rate varies by manufacturer, but mine is around 40 lpm.
The unvented cylinder does not have this effect. Obviously, 40 lpm @ 60C is enough for most people, and the heat bank can be specified with a larger heat exchanger, which could be useful in a commercial setting, such as sports changing rooms or a hotel, where 40lpm isn't enough during the rush for showers.
Christian.
That depends on what you are looking for from a shower. I like both.
.andy
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not if you have a tank to current regulatory specs..
14lpm does not equate to two showers. It's barely enough for one.For one shower that could be a bit more reasonable
.andy
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Perhaps, but you need to have high pressure for either, as low pressure won't actually push enough water through the shower head for a higher flow.
High pressure is a requirement, whilst high flow is a bonus.
Christian.
It all seems to hinge on the flow rate then. I seem to remember, when I had a new kitchen fitted a few years ago that a second stopcock was added in series with the old one because the old one has seized and was also inaccessable. I guess this may restrict the flow further?
I'm not familiar with 25mm MDPE. Where would it be fitted?
So it looks like this would be a good solution, if the flow rate was adequate?
Ah I understand now.
Cheers, M.
I'm not quite sure what you mean? You could wash more than adequately with someone holding a series of watering cans over you.
I only get 12-13 litres per minutes at those taps. I have have both taps on at the same time the flow drops off. :-(
M.
"Dave Plowman (News)" wrote | > High pressure is a requirement, whilst high flow is a bonus. | I'm not quite sure what you mean? You could wash more than | adequately with someone holding a series of watering cans over you.
And it would probably be more comfortable that being hosed down with a Karcher.
Bad Lads Army (telly) tonight showed how to wash yourself in a mess-tin of water. I expect the SAS can do that and have enough water left over to make a pot noodle.
Owain
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