MM 277G
Model RB-24E-S
Model RB-24E-A
Model RB-24E-L
Conductance Type
Low Water Cut-Off
with Universal Wiring Harness
For Residential
24 VAC Hot Water Boilers
INSTRUCTION MANUAL
MM-277G
• Before using this product read and understand instructions.
• Save these instructions for future reference.
• All work must be performed by qualified personnel trained in the proper application, installation, and maintenance of plumbing, steam,hot water and electrical equipment and/or
systems in accordance with all applicable codes and ordinances.
• To prevent electrical shock, turn off the electrical power before making electrical connections.
• 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 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 400,000 BTU/hour.At least two controls should
be connected in series with the burner
should the boiler experience a
low water cut-offs should be
calibration and performance.
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.
Failure to follow this warning could cause property damage, personal inj ury or death.
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.
low-water condition. Moreover, at each annual outage, the
dismantled, inspected, cleaned, and checked for proper
!
control circuit to provide safety redundancy protection
&
'
OPERATION
The Model RB-24E Low Water Cut-Off is specifically designed to provide burner cut-off if there is
an unsafe water
or
ken
tion
Water/glycol
may be used.
leaking radiator or pipe, or a cracked sec-
in
the boiler.
loss, which can result from a bro-
mixtures up to 50% concentration
SPECIFICATIONS
Temperature:
Storage: -40'F to 120'F (-40'C to 49'
Ambient: 32'F to 120'F (O'C to 49'C)
Humidity:
Maximum Water Pressure:
Maximum Water Temperature:
85% (non-condensing)
160 psi (11.2 kg/cm2)
250' F
C)
(121 'C)
3//
NPT
IMPORTANT: steam boilers.
Cable LED
Connector
=e;;=
R
ed
LED
Low Water
Do not use Model RB-24E on
On
~
~:ee
~
Test
Button
Electrical Ratings
Power
Voltage Consumption Switching Capacity
24VAC
Enclosure Rating:
2.5
VA
NEMA 1 General Purpose
RB-24E-S
2A at 24 VAC
PIN 144693
Do not use on
IMPORTANT:
The
boilers that have a transformer plug
connection to the aquastat.
• 5 foot connector cable
•
'V' harness for Honeywell Aquastat
• 'V' harness for United Technologies
burner control module
The
boilers that have a control panel plug
connection.
• 5 foot connector cable
systems.
RB-24E-S
RB-24E-L
is
for use on hot water
is
for use on hot water
millivolt
RB-24E-L
PIN 144690
INSTALLATION -
TOOLS NEEDED:
Pipe wrench or channel lock pliers.
2
RB-24E-A
PIN 144694
is
RB-24E-A
The
boilers that have a vent damper.
• 5 foot connector cable
•
6 pin connector 'V' hamess
• 4 pin connector 'V' hamess
for use on hot water
STEP 1 - Electrical Wiring Options
A
'"'
.
~
",
~
To
prevent electrical shock,
•
This
low
the
water
boiler.
leaving
to
follow
After
•
on
before
Failure
cut-off
installation,
the
site.
this
warning
must
turn
be
could
off
the
installed
check
for
cause
electrical
a
WARNING
power
in
series
proper
property
with
operation
damage,
before making electrical
all
other
limit
and
of
all
of
personal
the
injury
operating
limit
connections.
controls
and
operating
or
death.
installed
controls,
RB-24E-A 4-Pin Damper
with GRAY
Install angle bracket (1)
Color Tubing for Atmospheric Boilers
on
vent damper using
Harness
'Y'
fitting (2) and nut (3).
®
Install BX connector to angle bracket.
®
Plug 4-pin connector of 'Y' harness to 4-pin
connector
@
Plug 4-pin connector of boiler's vent damper
on
vent damper.
Boiler Vent
Damper Wire
Harness ·
wiring harness to connector of 'Y' harness.
NOTE
This
'Y' Harness can
with
vent
RB-24E-A 6-Pin Damper
Harness
'Y'
used
4-pin connectors.
with BLACK Color Tubing for Atmospheric Boilers
"Y" Harness with -
GRAY Color Tubing
..
~
only
dampers
~
with
be
.
~~I
~
..
If
Remove 6-pin connector of damper wiring
®
harness from connector
®
Plug 6-pin connector of damper 'Y'
harness to connector
©
Plug connector of damper 'Y' harness to
connector of
boiler's damper wiring harness.
on
on
aquastat.
aquastat.
NOTE
'Y'
This
used
6-pin connectors.
Harness can
with
vent
dampers
only
be
with
Aquastat
"Y" Harness
BLACK
Ceilor
with
Tubing
3
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