2
Determine which situation applies:
a. For models 51-2, 51-S-2 or 53-2 on steam boilers:
Always set the control to shut off the burner while
there is water visible in the gauge glass. This applies
when the gauge glass is directly mounted in the boiler
or on a water column.
b. For models 51, 51-S or 53 on steam boilers:
Set the line on the casting 3
1
/
8
" below the boiler
manufacturer’s normal water level.
c. For all models on steam process boilers when no
condensate is returned to the boiler:
Set the line
on the casting 1
1
/
8
" below the boiler manufacturer’s
normal water level.
Models 51 / 51-2, Models 51-S / 51-S-2 and Models 53 / 53-2 –
For Steam Boilers with 1” (25mm) Equalizing Lines
INSTALLATION –
TOOLS NEEDED:
One (1) flathead screwdriver and two (2) pipe wrenches.
STEP 1 - Determine the Location of the Feeder and/or Low Water Cut-Off
Operating Levels of 51/51-2,
51-S/51-S-2 or 53/53-2
Drip tight valve off – 1
1
/
8
"
Casting line
– 0”
Burner on
–
1
/
8
" (±
1
/
4
")
Burner off
–
7
/
8
" (±
1
/
4
")
Series 51 and 53 Operating Level
Valve Off -1
1
/
8
"
Casting Line - 0"
Burner On -
1
/
8
" (
±
1
/
4
")
Burner Off -
7
/
8
" (
±
1
/
4
")
Casting
Line
Failure to follow this warning could cause property damage, personal injury or death.
California Proposition 65 warning! This product contains chemicals known to the
•
state of California to cause cancer and birth defects or other reproductive harm.
Previous controls should never be installed on a new system. Always install new
•
controls on a new boiler or system.
CAUTION:
A more frequent replacement interval may be necessary based on the condition of
the unit at time of inspection. McDonnell & Miller's warranty is one (1) year from date
of installation or two (2) years from the date of manufacture.
•
