Xylem MM 110C User Manual
Model PFC-1-G (direct acting)
PFC-1-GR (reverse acting)
Modulating Pneumatic
Liquid Level Controls
APPLICATIONS:
– Use with other pneumatic devices, for liquid level
sensing in tank or pressure vessel where electrical
processes are not suitable, such as certain hazardous
locations.
Features:
– A float-operated, modulating, pneumatic level controller
– Side-mounting pipe connections
– Direct or reverse action convertible
– Field adjustable operating range & proportioning band
INSTRUCTION MANUAL
MM-110C
Ratings:
Maximum Vessel Pressure: 250 psig (17.6 kg/cm2)
Maximum Fluid Temperature: 406° F (208°C)
Maximum Supply Air Pressure: 20 psig (1.4 kg/cm
CAUTION
WARNING
• Before using 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, and electrical equipment and/or systems in accordance
with all applicable codes and ordinances.
• If tank or receiver is pressurized relieve pressure to 0 psi (0 Bar) before servicing.
Drain water level down and let cool to 80°F (27°C).
• Boiler manufacturer schematics should always be followed. In the event that the boiler
manufacturer's schematic does not exist, or is not available from the boiler manufacturer,
refer to the schematics provided in this document.
• To prevent water damage check to make sure there is adequate floor drainage capacity.
Check all components in the system to insure they will not leak in the event of an
overfeed condition.
• After installation, check for proper operation of all of the limit and operating controls before
leaving the site.
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.
2
WARNING
!
!
)
&
'
2
The model PFC should be installed vertically on the side
of the tank or vessel and connected with 1” equalizing
pipes. Plug all unused body connections. Control must be
plumb, with no more than a 2°-3° slant in any direction.
Control should be set with mark on casting 1” below the
desired operating level in tank. Keep equalizing lines as
short as possible and avoid creating any pockets. Crosses
with plugs should be used at any right angle connections
to facilitate cleaning. A blow-off valve should be installed
to permit blowdown operation and draining the float
chamber. All connections must be securely tightened in
leak-tight arrangement.
Gauges should be positioned for convenient reading.
Head assembly can be reoriented by removing 8 bolts in
the top of the head assembly and repositioning the entire
head as desired so gauges can be read conveniently.
Piping Hook-up
INSTALLATION –
Boiler / Hydronic Installation
TOOLS NEEDED:
Two (2) pipe wrenches, one (1) flathead screw driver
and pipe thread dope.
FACTORY SETTINGS
DIRECT ACTING—MODEL PFC-1-G - The higher the liquid
level, the higher the output pressure. Control can be changed
to Reverse Acting.
REVERSE ACTING—MODEL PFC-1-GR - The higher the liquid
level, the lower the output pressure. Control can also be changed
to Direct Acting.
NOTE: Pneumatic operated valves are also available as either
Direct Acting or Reverse Acting.When control and valve are the
same –both Direct Acting or Reverse Acting– the valve opens
as liquid level falls. When they are not the same, valve opens
as level rises.
MAXIMUM PROPORTIONAL BAND—Control goes through
its full operating range—from 3 to 15 psi output— with 2” of
level change inside the float chamber. The proportional band
can be adjusted to as little as 1” of level change.
SET POINT—The mark cast on float housing indicates the
low point of the control operating range. The operating level to
be maintained in the tank should be 1” above this mark. This
set point can be field adjusted about 3/4”.
OPERATION
The model PFC is float operated, and
mounts on the side of the tank or pressure
vessel. Its design allows field adjustment of
operational level, adjustment of proportional
band and conversion to either direct acting
or reverse acting operation.
Remove float blocking plug and dowel pin, located
in the bottom tapping of the control, before installation. Remove cardboard stop inside the top housing
before putting control in operation.
When using tape sealants on pipe or fittings external
threads follow the manufacturer's instructions—do
not place tape on first thread. When using thread
joint compound on pipe or fittings external threads
follow manufacturer's instructions—use sparingly
do not place compound on first thread.
!
CAUTION
Operating
Range
Proportional
Band
Output Air
2" (51mm)100%
1" (25mm)50%
3691215
(.2) (.4) (.6) (.8) (1)
Reverse
Acting
Direct
Acting
psi
(kg/cm
2
)
NOTE
The control is factory set to the mark on the float housing and
to maximum proportional band. If the proportional band is
adjusted, the point of minimum output may be as much as 1/2”
above the mark.
Be sure to release pressure from float chamber
before removing the 8 bolts.
!
CAUTION
IMPORTANT
Follow the boiler manufacturer’s instructions along with all
applicable codes and ordinances for piping, blow-down valve,
water gauge glass, tri-cock and electrical requirements.
OUTPUT AIR TO
CONTROL DEVICE
SUPPLY AIR
BALL VALVE
GATE VALVE
1”
DUAL
VALVE S
FOR
BLOW
DOWN
NORMAL
OPERATING
LEVEL
Loading...