Read and understand these instructions completely before installing or servicing this control.
Save these instructions for future reference.
Disconnect power supply before beginning installation to prevent electrical shock or equipment
damage.
Only qualified personnel may install or service the control in accordance with local codes and
ordinances.
This low water cut-off must be installed in series with all other limit and operating controls installed on
the boiler. After installation, check for proper operation of all of the limit and operating controls, before
leaving the site.
We recommend that secondary (redundant) Low Water Cut-Off controls be installed on all steam
boilers with heat input greater than 300,000 BTU/hour or operating above 15 psi of steam pressure.
At least two controls should be connected in series with the burner control circuit to provide safety
redundancy protection should the boiler experience a low water condition. Moreover, at each annual
outage, the low water cut-offs should be dismantled, inspected, cleaned, and checked for proper
performance.
To prevent serious personal injury from steam and hot water make sure there is a discharge line from
the blow down valve to a proper place of disposal.
To prevent a fire, do not use this low water cut-off to switch currents over 7.4A, 1/3 Hp at 120 VAC or
3.7A, 1/3 Hp at 240 VAC, unless a starter or relay is used in conjunction with it.
Previous controls should never be installed on a new system. Always install new controls on a new
boiler or system. Failure to follow this warning could cause property damage, personal injury or
death.
CAUTION
A more frequent replacement interval may be necessary based on the condition of the unit
at time of inspection. Hydrolevel’s warranty is two (2) years from the date of manufacture.
WARNING
126 Bailey Road, North Haven, CT 06473 • Phone (203) 776-0473 • FAX (203) 764-1711 •
www.hydrolevel.com
711 Series
Low Water Cut-Off
Feeder Combination
for Steam Boilers
120 VAC Operating Voltage
No moving parts in water.
No floats to hang-up or foul.
Unique two probe design.
Bouncing water line won’t
cause on-off burner cycling or
water valve slamming noise.
Easy installation. Quick
hook-up fittings adapt control
to all 8" to 14" sight glasses.
Simple fast wiring. Can
be used with any standard
automatic water feeder.
