Central Heating System Advice

Special points

Install boilers strictly in accordance with the maker’s instructions, allowing, for conventional-flue boilers, an adequate air supply. Boilers should stand on a level and fireproof surface, and special care should be taken to conform with local fire and safety requirements.

Make sure that the gravity return pipe to the boiler does not return below the boiler base. This is because the effective resistance of a gravity return pipe can be as much as six times more than that of a rising gravity pipe and could mean a loss of natural circulation.

Never combine the cold-feed and expansion pipes, as this could entrap air in the boiler, with damaging results. Where connection is made to the lower part of the boiler pipework, air is pushed up the safety pipe as the system fills.

Locate draincocks at lowest points in the circuit and at the base of both the boiler and the hot-water cylinder. This will enable the circuit to be drained down partly or fully when necessary.

Filling up

After filling the system with water, all radiators and air cocks should be open to ensure that air is expelled. The water temperature may be raised to half the working temperature for about half an hour and the pump switched off.

Re-vent the system and the pump to clear air collected by the rise in temperature. During the first few weeks of operation, the system should be vented from time to time, to ensure that all air has been expelled.

With a microbore or other system fitted with automatic air venting, this process is carried out automatically.

Pipe bores should be clean and boilers should be flushed out at least twice before starting the pump. It is sound practice to flush the system again after it has been operating for some weeks.

10. November 2011 by admin
Categories: Featured, Handyman Tips | Tags: , , , , , , , , , | Comments Off on Central Heating System Advice


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