Hydronic heating is environment-friendly/economical system for commercial complexes.
Step 1-Open Vented Heating
Check draincock, on return pipe, with rubber hose for appropriate drainage. Turn off boiler; leave the pump on. After cooling, turn the pump off.
Step 2-Turn Water Supply Off
Turn off water supply to loft. Dissolve the ball valve.
Step 3-Fix Ball Valve and Draincock
Adjust ball valve arm to level. Place a batten across tank, and ball valve arm on top. Attach batten to valve arm. Put one hose end on draincock near boiler and the other at the gully. Use adjustable spanner for drainage.
Step 4-Check Water
Water is left in hydronic system for the radiator vacuum.
Step 5-Open Bleed Valve
Open bleed valve on a single radiator; start with radiators on top. After main system drainage, check individual draincocks in inverted loops.
Step 6-Fill Open-vented Heating System
Fill heating system with expansion tank and feed. This is automated, handled by ballcock and ball float.
Step 7-Close Bleed Radiator Valve
After drainage, turn stopcock back or untie ball-valve arm.
Use chemicals in central heating system, with self-contained heating unit.