Replacement Parts List

24
Boiler Control Replacement Parts
BOILER CONTROLS
Low Water Cut-Off/Pump
Controllers For Steam Boilers
Series 150, 150S
Series 157, 157S
The Series 150S is available as an alternative for
Series 150 LWCO controls that contain mercury
switches. Please keep in mind that in a replacement
or repair situation you do not have to change out the
entire control. A head replacement (i.e. 150S-HD) is
all that’s required.
There may be additional letters such as ‘B’, ‘R’, ‘RL’,
etc. in the sales catalog designation of the control.
These additional letters designate tapping locations
and sizes which have no affect on which head
mechanism to purchase. All head mechanisms are
interchangeable and can be installed on any body.
‘MD’Models
The ‘MD’ model should be used as a replacement
head when the boiler operating pressure is less than
50 psi. These were created to provide a control with
factory settings to compensate for the narrowing of
setpoints. The larger differential between pump on
and burner off reduces the potential for nuisance
burner shutdown.
It is important to understand that there are
requirements that lead to the best performance
of ALL level controllers and LWCO’s:
• Use of properly-sized pump starters/relays
in the pump control circuitry
• Pumps that are balanced to the system
requirements
• Equalizing piping, per the boiler manufacturer’s
recommendations, to properly sense the
boiler water level
• Industry accepted blowdown piping to provide
best cleaning action of the control chamber, float
linkage mechanism and/or probes
• Proper periodic blowdown of the boiler controls.
• Proper chemical treatment of boiler water.
• Annually cleaning and careful exam-
ination of the float mechanism, probes, and
electrical switches or controls. More frequent
cleaning may be required for exceptionally
dirty steam systems.
150 or 150S
Float Chamber Body
157 or 157S
Water Column Body