Disconnecting wet-back water heaters

Explosions have occurred recently because wet-back water heaters were unintentionally reused after the wet-back had been disconnected.

The installation of a wet-back water heater requires a great deal of care and skill to ensure that the heated water can easily circulate, thus preventing a small volume of water from being heated, turning to steam, building up pressure, and exploding.

If a wet-back water heater is ever disconnected, it must never have the pipes to and from the wet-back sealed. Any water that is deliberately or accidentally left in the wet-back can cause an explosion if it is heated.

Ideally, all disconnected wet-back heaters should not have the pipe fitting installed in the pipe ends, sealing the wet-back.

If this is not practicable, a 6 mm hole must be drilled through each plug. This will help to ventilate and dry the inside of the wet-back and will prevent pressure build-up if the wet-back is accidentally heated.

The installation and disconnection of wet-backs should only be undertaken by a qualified and licensed plumber.