D
denners
Hi all
I've been looking at options for replacing our knackered old gas boiler with Y plan gravity fed central heating / hot water system and could do with some advice. We are in a 3 bed (2 person) mid terrace, only 1 bathroom but we like a good shower and don't fancy electric shower or combo boiler for this reason, but also want rid of the tanks in the loft (to reduce water damage risk and free up valuable space). The hot water cylinder (120 litres), pump and mid position valve are all in the same place (airing cupboard) so I'm hoping that we can make reasonable changes to the system without ripping up floors/walls etc. Mains water pressure is high and water is soft here so no worries there. I am also interested in the possibility of adding solar thermal possibly now, but at least leaving the option to add it at a later date to whatever system we put in now.
So I've been reading around and had a couple of quotes, and our options seem to be:
1) Unvented cylinder (120litre ish megaflow or similar) for DHW, and convert CH system to mains fed (would need a small 10litre ish expansion vessel)
Advantages:
Several plumbers around here (Ayrshire) are used to them and could fit them!
Better flow rate for hot water?
Simpler replacement for current system?
Disadvantages:
Less efficient use of solar thermal?
Requirement for annual inspection
The thought of having something potentially explosive (yes I know this is unlikely) in the airing cupboard
2) Small (120-150litres) heat bank for DHW with CH system as for (1)
Advantages:
More efficient use of solar?
More efficient use of heat generally through stratification and allowing the new boiler to fire for longer periods rather than frequent short bursts?
Not pressurised
Disadvantages:
Slightly more expensive to fit than (1)
Smaller heat banks (to suit our needs) less efficient than larger heat banks?
Reputation for building up sludge?
I'm having trouble finding a heating engineer/installer in the area that has experience with them...
3) Slightly larger (maybe 150-200litres) heat bank for DHW and CH (probably direct feed to CH to make use of single F&E tank, which means system and radiators will need a good flush!)
Advantages:
As for (2) plus potential use of solar for CH and end up with simpler system?
Disadvantages:
As for (2) plus slightly more complicated to convert existing setup?
Based on my (limited) knowledge, I'm leaning towards option (3) as it seems the most elegant and long term most efficient / cheapest to run. But there seems to be some very strong opinions (pro and con) re heat banks floating around and I'm not sure what to believe.... So my questions are:
Does this summary seem reasonable? Anything you disagree with?
Given that I am changing the boiler at the same time, am I better to go with a closed system boiler and indirect feed to the tank or vented system boiler and direct feed to the tank for option 3 (I assume condensing boiler on sealed system is better for options 1 and 2)?
Any positive or negative experiences with heat banks or unvented cylinders that you would like to share?
Can anybody recommend a good heat bank system with solar, gas and immersion heater connections that will drive DHW and CH (it looks like external plate heat exchanger systems are better for DHW, but advice welcome)?
Is any particular boiler type best for this system?
Can anyone recommend someone (or themselves!) to supply and install this system (+/- solar thermal depending on cost) in the Glasgow area?
Any advice greatly appreciated!
Thanks,
Matt
I've been looking at options for replacing our knackered old gas boiler with Y plan gravity fed central heating / hot water system and could do with some advice. We are in a 3 bed (2 person) mid terrace, only 1 bathroom but we like a good shower and don't fancy electric shower or combo boiler for this reason, but also want rid of the tanks in the loft (to reduce water damage risk and free up valuable space). The hot water cylinder (120 litres), pump and mid position valve are all in the same place (airing cupboard) so I'm hoping that we can make reasonable changes to the system without ripping up floors/walls etc. Mains water pressure is high and water is soft here so no worries there. I am also interested in the possibility of adding solar thermal possibly now, but at least leaving the option to add it at a later date to whatever system we put in now.
So I've been reading around and had a couple of quotes, and our options seem to be:
1) Unvented cylinder (120litre ish megaflow or similar) for DHW, and convert CH system to mains fed (would need a small 10litre ish expansion vessel)
Advantages:
Several plumbers around here (Ayrshire) are used to them and could fit them!
Better flow rate for hot water?
Simpler replacement for current system?
Disadvantages:
Less efficient use of solar thermal?
Requirement for annual inspection
The thought of having something potentially explosive (yes I know this is unlikely) in the airing cupboard
2) Small (120-150litres) heat bank for DHW with CH system as for (1)
Advantages:
More efficient use of solar?
More efficient use of heat generally through stratification and allowing the new boiler to fire for longer periods rather than frequent short bursts?
Not pressurised
Disadvantages:
Slightly more expensive to fit than (1)
Smaller heat banks (to suit our needs) less efficient than larger heat banks?
Reputation for building up sludge?
I'm having trouble finding a heating engineer/installer in the area that has experience with them...
3) Slightly larger (maybe 150-200litres) heat bank for DHW and CH (probably direct feed to CH to make use of single F&E tank, which means system and radiators will need a good flush!)
Advantages:
As for (2) plus potential use of solar for CH and end up with simpler system?
Disadvantages:
As for (2) plus slightly more complicated to convert existing setup?
Based on my (limited) knowledge, I'm leaning towards option (3) as it seems the most elegant and long term most efficient / cheapest to run. But there seems to be some very strong opinions (pro and con) re heat banks floating around and I'm not sure what to believe.... So my questions are:
Does this summary seem reasonable? Anything you disagree with?
Given that I am changing the boiler at the same time, am I better to go with a closed system boiler and indirect feed to the tank or vented system boiler and direct feed to the tank for option 3 (I assume condensing boiler on sealed system is better for options 1 and 2)?
Any positive or negative experiences with heat banks or unvented cylinders that you would like to share?
Can anybody recommend a good heat bank system with solar, gas and immersion heater connections that will drive DHW and CH (it looks like external plate heat exchanger systems are better for DHW, but advice welcome)?
Is any particular boiler type best for this system?
Can anyone recommend someone (or themselves!) to supply and install this system (+/- solar thermal depending on cost) in the Glasgow area?
Any advice greatly appreciated!
Thanks,
Matt