My lady doth protest too much.
Unvented vs vented cylinder
- Thread starter ivixor
- Start date
My lady doth protest too much.
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If one is going to throw stones.... 
The Atmos boiler is the older version of the Intergas ( one source being Dan Robinson in a 2013 post )
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Atmos still isn't Intergas. Daalderop isn't Intergas. Atmos isn't Daalderop
FFS, how hard is it to comprehend?
FFS, how hard is it to comprehend?
That looks a bit odd in that the CH flow and return are shown on the cylinder. But if you have weather compensation (internet connected or not!) the CH water temperature is reduced when outdoor temp rises. I've never had one, but I believe it works by in effect lowering the boiler control-stat setting when CH calling, but reverting to higher setting when HW calling. Can't do that if the higher temperature is needed for HW. Of course it could be done by feeding the cylinder and the rads separately via a diverter valve, but then the CH connections on the cylinder are not needed.Just one maker. Many around.....
Thermal Stores
Thermal stores take a completely different approach to delivering hot water.
Rather than drawing from the stored hot water, the thermal store forces the mains pressure cold water through a high efficiency heat exchanger coil which draws its heat from the surrounding “Thermal Store” to heat the water for the taps.
The thermal store approach offers a number of benefits depending on the application:
- Extremely energy efficient reducing running costs
- Can be used with Solid Fuel
- Can run central heating from the thermal store
- Instant hot water and heating
- Extremely reliable as there are fewer mechanical components
- Easy to install
- No annual maintenance
- Fresh mains water at hot and cold taps
- Zero legionella risk as no stored water is fed to taps
- No risk of explosion
- No large pressure relief pipe through outside wall
- No recharging of pressure vessel
- No complex, expensive, pressure controls
https://www.mcdonald-engineers.com/thermal-store-vs-unvented-cylinder
This brings another question to mind - on a conventional pump, diverter valve/HW cylinder system with weather compensation, if it's a mid-position valve, what does the temperature control do when both CH and HW are calling?
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It has water in the cylinder heated by the boiler. This water is stagnant, it goes nowhere being a heat transfer stored at low pressure. Cold water enters the coil and is heated by the stored hot water, coming out hot under high pressure. The header tanks just tops up the main body of the water in the cylinder. Very simple.
I know, that's the point I'm making. The water in the cylinder has to be hot to transfer heat to the coil, so if the cylinder and CH are a common system the boiler flow temperature can't be reduced by the weather compensation, or the HW won't be hot enough.
With a hot water only thermal store that does not apply as you will use a diverter valve.
If you want a CH & DHW thermal store and weather compensation, then fit a stand alone compensator and modulating valve, which will be expensive as you are moving into commercial, and use a cheaper basic no frills boiler to heat it. Or, when the flow switch is activated have it also energise a relay which either cuts out the outside sensor or bypasses it giving zero resistance (depending on outside sensor), sending the boiler to maximum temperature. So when DHW is called full heat is sent from the boiler to the top of the cylinder, to be drawn off and sent to the DHW plate heat exchanger. Have the CH flow tapped off the cylinder about a third down the cylinder.
Easy.
If you want a CH & DHW thermal store and weather compensation, then fit a stand alone compensator and modulating valve, which will be expensive as you are moving into commercial, and use a cheaper basic no frills boiler to heat it. Or, when the flow switch is activated have it also energise a relay which either cuts out the outside sensor or bypasses it giving zero resistance (depending on outside sensor), sending the boiler to maximum temperature. So when DHW is called full heat is sent from the boiler to the top of the cylinder, to be drawn off and sent to the DHW plate heat exchanger. Have the CH flow tapped off the cylinder about a third down the cylinder.
Easy.
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D
durhamplumber
Thermal stores are a load of crap
D
durhamplumber
Indeed.what could possibly go wrong!
If you knew anything about heating and water system you would come out with such an inane silly comment. So best not comment on fields you know little. Maybe drains is your forte.
I doubt you understood much of what I wrote at all. Look at the pressure and temperature controls on unvented cylinders. What could go wrong? Someone on another thread posted a vid of an unvented cylinder exploding.
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durhamplumber
Having worked on many of the broken afore mentioned items I understand precisely what you are on about
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