D
Deleted member 105431
surely that depends on the incoming mains temp, dhw target temp and flow rate?
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- Thread starter Locoblade
- Start date
surely that depends on the incoming mains temp, dhw target temp and flow rate?
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I'm sure that if it was possible that any manufacturer would be only too pleased to include it in the promo literature.
They add in far more 'doubtful' info that this all the time to try to persuade us to fit their brand.
They add in far more 'doubtful' info that this all the time to try to persuade us to fit their brand.
D
Deleted member 105431
why would you make a statement that is effected by so many variables?
a low incoming mains temp with a high flow rate would cause most premix steamers to condense I would think.
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Yes but if you had a cylinder you wouldn't have to worry about the mains being warm enough to have a hot bath.
They are,your getting confused with what we are all talking about here.
Unvented cylinders with top quality insulation and large coils (X2) coupled to a high output system boiler will be *almost as efficient* as a combi however a *normal cylinder* will be more expensive even coupled to a system boiler.
Tony.
Any normal condensing boiler will be well condensing when delivering DHW at about 43° whether the manufacturers bother to put that in their brochures or not.
If you dont want to believe me then find one and run it and see the condensate coming out!
However, thats not the point! A cylinder will require about 2 kWh per day to make up the heat loss. Thats about 12p for gas and electricity. Pretty negligible.
The fact is that a cylinder will dump more hot water in your bath quicker than any combi or serve several hot water outlets at the same time.
I therefore recommend that you have a modern cylinder and a heat only boiler matched to the heat loss of your property plus 2 kW as recommended.
Any further money you want to spend should be on insulation as thats where you will save money. 80-90% of the gas bill is for heating!
Tony
If you dont want to believe me then find one and run it and see the condensate coming out!
However, thats not the point! A cylinder will require about 2 kWh per day to make up the heat loss. Thats about 12p for gas and electricity. Pretty negligible.
The fact is that a cylinder will dump more hot water in your bath quicker than any combi or serve several hot water outlets at the same time.
I therefore recommend that you have a modern cylinder and a heat only boiler matched to the heat loss of your property plus 2 kW as recommended.
Any further money you want to spend should be on insulation as thats where you will save money. 80-90% of the gas bill is for heating!
Tony
I often wonder why I only seem to understand about half of what others say on some forums!
Hi Tony
I'm assuming "normal" means an unvented cylinder, and you're saying here that new vented cylinders aren't as well insulated and don't have such good coil designs as unvented ones? I think thats the first time a differentiation has been made between cylinder types in this thread though, hence the apparent confusion. I assumed whether vented or unvented, the insulation and warm up characteristics of a good quality tank would be similar.
Cheers Tony, its not me disbelieving anyone, just trying to get my head around the apparent contraditions of various posts
Thanks for your input.
No by normal I mean a typical vented cylinder say 900MMX450MM. Recovery time will be about 20mins depending on the primaries and type of boiler etc but about 20mins or so but the heat loss will not be as good as something like below.
A decent unvented 200 ltrs cylinder,for example, will have a recovery time of about the same depending on etc etc however the heat loss will be minimal meaning that unless you use hot water then the boiler will hardly fire over a 24 hr period and your water will still be pretty hot.
These are about as good as you'll get .
http://www.mcdonald-engineers.com/products/index.htm
Have a look at the different options but check out the differences between the Powerflow range and the open vented cylinder range which should perhaps enlighten you a wee bit.
Tony.
PS, I think you should still go for a Combi
PPS,the 250 litre powerflow cost me about £1200 18months ago so you can add about £200 to that price now.
Cheers Tony, having looked at the link Im still struggling to understand why a top spec brand new vented cylinder (e.g. Hyper Cylinder?) can't have equal heat loss characteristics to an unvented one because surely its just a matter of putting additional insulation around it, but happy to take your word for it if the way an unvented tank works means it will cool quicker.
Fancy a career change? By the time this thread has ended you'll be more familiar with heating systems than I am
This is what GFU was on about
http://www.mcdonald-engineers.com/products/fastheat.htm
A 24 KW boiler will reheat the cylinder in 6 mins and it looks as though that cylinder has 100MM of insulation whereas a normal open vented cylinder has about 50MM of insulation.
Same applies with the likes of the Powerflow range,lots of insulation and large coils to heat the water quickly and keep it hot but remember the cost of these things,
Here are the specs for the Powerflow range,
http://www.mcdonald-engineers.com/products/powerflow_specs.htm
Have look at these too,might be the way to go seeing as your intent on storing water
http://www.mcdonald-engineers.com/products/solar.htm
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