here's photos of one being installed
http://www.ultimatehandyman.co.uk/forum1/boiler-a-half-t2428.html
http://www.ultimatehandyman.co.uk/forum1/boiler-a-half-t2428.html
Vaillant EcoTEC plus 937
- Thread starter Stephen19
- Start date
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Although the size of a combi is determined by the hot water performance, the heating requirement is just as important. The 937 can only modulate down to 12kW - below that it goes into on-off mode. 13 radiators does not seem all that large - I have that and it is fed from a 14kW non-condensing regular boiler.
Use the Sedbuk Boiler Calculator to find out how big a boiler is required just for heating - the result includes 2kW for hot water, so that should be deducted from the total. You should also use the Stelrad Elite Catalogue to estimate the output of your existing radiators, to make sure they are large enough - larger is better than smaller.
The calculated boiler kW needs to be well above 12kW or the 937 will spend most of its time in on-off mode.
All Broag boilers modulate down to 6kW, so they may be more suitable.
http://s363.photobucket.com/albums/oo71/david938/?action=view¤t=IMG_3725.jpg
The control panel cover cannot open fully but it is still reasonably easy to access.
A combi boiler will not run two bathrooms at the same time. Combis are should be used when space is at a premium. If you have a loft put a boiler cylinder and tank up there and possibly a pump if you like decent showers. Some one will also suggest and unvented horizontal cylinder which are ok if you want to pay for a £150 service charge every year.
We are used to a combi now and would not need it to run two items at same time. Space is not at a premium so we wonder if its still ok to have one in a larger dwelling place? We have a sealed system there at present with hot water tank etc. We would only need up to the EcoTECH 837 combi if we took that option or the Vaillant 630 system boiler if we went that way. Its a 'hard water' area.
What makes you think you need such a large boiler? Is your house enormous?
As I have said earlier, check out what size boiler you really need for heating using the Sedbuk Boiler Calculator. I would be very surprised if you need a system boiler larger than a EcoTEC plus 618.
The 837 suffers from the same problem as the 937 - it can only modulate down to 12kW, which may not be low enough for your house.
You may well be correct but isnt the one down from the 837 the EcoTECH plus 831? This goes down to 8.7kw (& up to 24kw). Would 12kw be too high a start point for an internal building space of 1631sq ft?
Floor area is not enough to go on; there are other factors to consider!
Instead of speculating, why not use the Sedbuk calculator - then you will have an accurate answer. The heating requirement could be anything between 6kW and 20kW, depending on windows, insulation, construction and location.
Floor area is not enough to go on; there are other factors to consider!
Instead of speculating, why not use the Sedbuk calculator - then you will have an accurate answer. The heating requirement could be anything between 6kW and 20kW, depending on windows, insulation, construction and location.
Had a look at that calc item and it was asking for all sorts of measurements which I do not have, like windows etc. I have an open mind on the actual boiler model but do wish to go for a Vaillant. I started with idea of 937, then after coments thought 837 and then maybe 831. It will depend on the actual survey from the visiting engineer IF and WHEN we move in. BUT I do want plenty of capacity for growth and change, hence my idea to 'go large'. And I stick by that concept. But now I know that I have to consider the lower end performance too, so thanks for that learning.
The only measurements you have to input are: length, width, room height and number of floors. You do NOT have to work out the window area; it will be estimated for the type of house. The answer may not be 100% accurate; but it's better than guesswork.
The 831 does go lower, but is it low enough? In any case if you go for the 831 you will only get a hot water flow rate of 12.7 litres/min compared with 15.2 for the 837. This illustrates the problem with combi boilers - what is required for hot water may conflict with what is required for heating.
A system boiler may be a better choice as you only need to provide an additional 2kW (some say 3kW) on top of the heating requirement for hot water.
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The only measurements you have to input are: length, width, room height and number of floors. You do NOT have to work out the window area; it will be estimated for the type of house. The answer may not be 100% accurate; but it's better than guesswork.
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Nah, it asks for a whole lot more measurements than that.
It lost me on the question of - No. ext walls length-wise and then again width-wise??? Its a 4 sided house ! Tried again and came out need for just 10kw.
The only measurements you have to input are: length, width, room height and number of floors. You do NOT have to work out the window area; it will be estimated for the type of house. The answer may not be 100% accurate; but it's better than guesswork.
[/quote]
Nah, it asks for a whole lot more measurements than that.
It lost me on the question of - No. ext walls length-wise and then again width-wise??? Its a 4 sided house ! Tried again and came out need for just 10kw.
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