Having a chat with colleagues on this one to decide on best route.
Existing 500L megaflo which does not provide sufficiant HW.
Cold water entering cools the hot way too quickly and consequently the 500L is good for about half that.
Coil is 54kw boiler is 80kw
Cylinder options…
The cylinder has 6 physical connections.
1 & 2 coil (heat input)
3, Cold feed
4, Hot Out
5, Secondary return
6, T&P
Option 1 - virtually normal setup
Heat tank water via coil
Use hot out & SR port for plate flow
Cold for fill and expansion 500l
Prv for relief
Pros
Limits heating system water for expansion
Keeps primary plate cleaner
Cons
Very limited use as a heating buffer via 12kw Immersion heater
Unvented controls still required
Option 2 - Buffer.
Cylinder water is heating system water.
Plate flow is on Hot out and return in to cold, NRV to return only to boiler with bypass in place for cylinder ZV Off or omit NRV for simplicity.
Heating Flow is in to PRV port
Heating Return is out from Cold
Secondary return is in with cold main on plate secondary via double check valve. Similar setup to Solar Thermal with thermal store.
Pro’s
500 L of stored water also available for heating system via 12kw immersion backup
Coil free for heat pump/solar
No need for additional Unvented controls separate from boiler.
Cons’s
Increased heating system volume expansion needs accommodating, around 650L
We cannot change the cylinder,
Your thoughts gents?
Existing 500L megaflo which does not provide sufficiant HW.
Cold water entering cools the hot way too quickly and consequently the 500L is good for about half that.
Coil is 54kw boiler is 80kw
Cylinder options…
The cylinder has 6 physical connections.
1 & 2 coil (heat input)
3, Cold feed
4, Hot Out
5, Secondary return
6, T&P
Option 1 - virtually normal setup
Heat tank water via coil
Use hot out & SR port for plate flow
Cold for fill and expansion 500l
Prv for relief
Pros
Limits heating system water for expansion
Keeps primary plate cleaner
Cons
Very limited use as a heating buffer via 12kw Immersion heater
Unvented controls still required
Option 2 - Buffer.
Cylinder water is heating system water.
Plate flow is on Hot out and return in to cold, NRV to return only to boiler with bypass in place for cylinder ZV Off or omit NRV for simplicity.
Heating Flow is in to PRV port
Heating Return is out from Cold
Secondary return is in with cold main on plate secondary via double check valve. Similar setup to Solar Thermal with thermal store.
Pro’s
500 L of stored water also available for heating system via 12kw immersion backup
Coil free for heat pump/solar
No need for additional Unvented controls separate from boiler.
Cons’s
Increased heating system volume expansion needs accommodating, around 650L
We cannot change the cylinder,
Your thoughts gents?