Closed Loop via Heat Exchanger

[deanalewis]

Hey Folks,

I have a closed loop heating system after my recent boiler upgrade I am on an Oil Fired Central Heating System.

I have a fireplace with a back boiler that is connected to the DHW but not the rads anymore because the new boiler changed the system to a Closed Loop from Open Vented e.g. the Expansion tank is disconnected.

I would like in winter to use the fireplace to heat the house so are my correct in thinking that if I reconnect the expansion tank and cold water storage tank back to the fireplace in effect making a seperate heating system for the fireplace - I could introduce a Metal Heat Exchanger to the closed loop system meaning that even if the oil boiler is off the house would still warm from the fire via in-direct heating via the heat exchange.

Does this make sense... In effect combining an open vented and closed loop via a heat exchanger?

 

[oldbutnotdead]

The time for contemplating this cunning plan was BEFORE you changed your boiler etc. A retrofit is going to be expensive and probably not ideal.
Some safety questions first. Is the back boiler on the fireplace still wet (ie is it still connected to live F & E tank).
You say the back boiler is connected to DHW- how is DHW heated in the summer (when fire isn't burning)?
Has the wet back boiler setup been properly tested and recommissioned as part of the main boiler change?