5.3102.36 Low Water Cutoffs

Topic: 
Hydronic Heating (Hot Water and Steam)
Subtopic: 
Equipment Installation
Desired Outcome: 
Prevent boiler from dry firing
TitleSpecification(s)Objective(s)
5.3102.36a
Primary low water cutoff

For steam boiler:

Mechanical low water cutoff will be installed in accordance with applicable codes and manufacturer's instructions at the proper water level

For hot water boiler:

Mechanical low water cutoff, electronic probe-type low water cutoff, or flow switch protection (in the case of coil boilers) will be installed in accordance with manufacturer specifications

A mechanical low water cutoff will be installed to include a discharge pipe and valve to allow for proper maintenance and safe discharge of boiler water during maintenance

Ensure burner will not fire under low water conditions

Ensure water discharges safely

Ensure proper location/ installation
5.3102.36b
Secondary low water cutoff

A secondary low water cutoff (electronic or mechanical) will be installed in accordance with applicable codes and manufacturer's instructions no more than 2" below the primary low water cutoff

A manual reset will be included on all secondary low water cutoffs

A secondary low water cutoff (electronic or mechanical) will be installed in accordance with applicable codes and manufacturer's instructions at or above the minimum safe water level as determined by the manufacturer; the primary low water cutoff shall be a minimum 2" above this elevation

Ensure backup to the primary system

Ensure proper installation location

Ensure water discharges safely
5.3102.36c
Control integration

If a central energy management system is available, low water cutoff will be connected to provide alarm

Support an immediate response to low water conditions
5.3102.36d
Testing low water cutoffs for steam boilers only

Primary low water cutoff:

Water level will be reduced to test cutoff operation using the following sequence:

  • Operate boiler (burner)
  • Open discharge valve
  • Note water level when burner stops firing

Secondary low water cutoff:

Secondary low water cutoff will be tested in a similar manner as the primary

Ensure proper working conditions

Ensure proper discharge
5.3102.36e
Education

Completed work will be reviewed with the building/property management team and operations staff

Building/property management team and operations staff will be educated on the safe and efficient operation and maintenance requirements of the installed item

Ensure building/property management team and operations staff is informed of the safe, efficient operation and maintenance requirements of the installed item