Hydro Level 400 24volt Steam Boiler Low Water Cut Off. 15 Second Burner Off Delay 30 Second Burner On Delay Automatic Reset Low Water Indicating Light Direct Boiler Mounting ? Eliminates Blowdowns Burner circuit contacts open after 15 second delay in a low water condition. Delay prevents short cycling caused by momentary fluctuations in the boiler water level. Automatically reactivates burner circuit 30 seconds after water reaches the probe, allowing optional water feeder to raise ...