boiler feed tank water level above stm boiler level

doug_10

A plumber asked me if the water level of the boiler feed tank can be above the steam boiler water line. He was worried the condensate will feed into the boiler without the feed pump. The existing boiler is a small Weil-Mclain EG75 steam boiler and because of site conditions, the tank was not installed directly on the floor. The condensate level could feasible rise above the water line of the boiler.

The residential boiler is operated off a single room thermostat and the pressuretrol is set for cutin at 2psig and cutoff at 1-1/2psig.

If the thermostat has not operated the boiler for an extended period and therefore the boiler pressure drops to zero, can the condensate from the feed tank push into the boiler and flood it?

Tony Conner

Unless...

...there's a valve that gets closed, either automatically, or by hand, the levels will equalize. This system was likely originally installed to work without a tank/pump. Is there a reason it was installed?