Gledhill thermal store

[sparky]

Just been to look at job changing a couple of rads on the above system. Large square tank (thermal store) with small i assume f+e tank on top expansion vessel for i think hot water. Also noticed a filling loop. Never seen this system before. Thermal store tank full of central heating system water and coil is for hot water i think. Just curious as to why is there a filling loop would have thought f+e tank would keep system topped up?

 

[Puddle]

The tank on the top just fills the thermal store unit itself,which is the tank /cylinder below,there are many variations to thermal stores ,looks like yours has maybe a coil inside or a plate heat exchanger on the out side that heats the heating circuit / radiators indirectly by the thermal store unit,this is the side that is pressurized,the heating circuit
Also you will see this set up allows mains water to be heated through a coil in the thermal unit and blended through to give hot water at mains pressure at outlets

 

[sparky]

Just a case of draining from rads and re filling from loop then. Inhibiter in rad on completion.

 

[Puddle]

Yes,be aware if gas boiler heating thermal unit it will/may be same water as in rads with 3 port valve set up going to rads and thermal store
Therefore make sure boiler off and vented correctly,if needed,when refilled
Good practice to turn everything off when draining part anyway

 

[sparky]

I think i saw a couple of 2 port valves on pipework will learn a bit about system(boilermate) before i mess.