Semi sealed system

mickf479

Hi folks. Just a quick question. my house has a semi sealed heating system ie expansion vessel in the hot press and tank for heating top up in the attic, im sick of getting air locks everytime i need to drain the system so was thinking of dumping the tank and bringing the mains from the tank into the heating feed in the hot press via a filler loop and sealing the system. will this work without damaging the boiler or expansion vessel???

DGOBS

it may do, but I would put a 24hr pressure test on the system before fully sealing and pressurising, to make sure there is no leakage.

Q: Why do you keep needing to drain and refill your system anyway? (idea is - not to!)

Pete67

Have you two tanks in the attic, or just one? Why does the system need to be drained frequently? Is there a solid fuel boiler/stove/back boiler? Need more information to advise on sealing the system.

Assuming a fairly standard 'semi sealed' system either gas or oil fired, it's probably fed from the cold water cistern in the attic via a check valve, this cistern also provides stored water for domestic hot and cold water - so you can't just get rid of the tank. You can probably convert the heating system to a sealed system fairly easily if the system is suitable, just use a filling loop and install a pressure gauge in the hot press so you can monitor the pressure in the system when filling. Disconnect the filling loop when not in use.

mickf479

Cheers folks. Not draining frequently but have replaced a rad or 2 in the past and new expansion vessel today. Just a pain dealing with air locks. Gas fired boiler no back boiler and a separate tank for cold water storage.