Page 6 – Bulletin 30-21
3-Way Split Condenser Valves
8D-SC, 12D-SC, 16D-SC, S8D-SC, S12D-SC, S16D-SC
The Split Condenser Valves are a relatively simple modifica-
tion of the standard Heat Reclaim Valves. Figure 7 shows that
the Split Condenser Valves only use the upper port; the lower
port is always open. The location of the seat disc has been
optimized such that when the valve is in the two condenser
mode, the flow is split evenly between the two condensers.
The pilot valve is different from the standard heat reclaim
valve. It is normally open to high pressure.
OPERATION
“B” and “C” Type
Two Condenser Mode - De-en er gized
See Figure 4. With the pilot valve de-energized, high side pres-
sure 1 is permitted to flow through the lower pilot port at the
same time the upper pilot port is closed to suction 2. High side
pressure 1 built on top of the piston moves the piston-seat
assembly down to evenly split the flow between the two con-
densers. The piston-seat assembly is held in place by a plate
located in the Condenser A connection. This plate is designed
to limit restriction through that port. With the upper pilot port
closed, there is no high to low side bleed and no resulting capac-
ity loss with the system in the two condenser mode.
Valves using the MKC-1 coil may be used on fluids or gases
where the temperature does not exceed 240°F (116°C), while
the valve ambient is 120°F (49°C). The coil is Underwriters
Laboratory Class F rated.
NOTE: If the pressure in your idle Condenser B is less than
the suction pressure that the suction connection of the valve is
connected to, you may have charge migration back into your
idle Condenser B. A small check valve in the suction pilot line
can be used to prevent this.
“B” (Bleed) Type
Single Condenser Mode - Energized
See Figure 5. With the pilot valve energized, high side pressure
1 is prevented from entering the cavity above the piston-seat
assembly. At the same time the upper pilot port is opened
to suction pressure 2. This opens the cavity above the pis-
ton-seat assembly to suction pressure 2. The cavity below
the piston is exposed to high pressure. The resulting pressure
differential across the piston moves the piston-seat assembly
up to close the upper (Condenser B) port. We use a solid pis-
ton ring on the piston, thereby eliminating high to low side
bleed around the piston. When the upper pilot port opens,
Condenser B is pumped out through a small bleed hole in the
piston. When Condenser B has been pumped out and reduced
to suction pressure, all flow ceases, thus eliminating high to
low side bleed and the resulting capacity loss that may occur
with the system in the single condenser mode.
“C” (No Bleed) Type
Single Condenser Mode - Energized
See Figure 5. With the pilot valve energized, high side pressure
1 is prevented from entering the cavity above the piston-seat
assembly. At the same time the upper pilot port is opened to
suction pressure 2. This opens the cavity above the piston-seat
assembly to suction pressure 2. The cavity below the piston
is exposed to high pressure. The resulting pressure differential
across the piston moves the piston-seat assembly up to close
the upper (Condenser B) port. A solid piston ring is used on the
piston thereby eliminating high to low side bleed around the
piston and the resulting capacity loss that may occur with the
system in the single condenser mode.
lower
pilot port
upper pilot
port
1
1
2
Figure 5
Pilot Valve
Energized
upper pilot
port
lower
pilot port
2
1
2
Figure 4
Pilot Valve
De-Energized
Condenser A
Summer/Winter
Check
Valve
Condenser B
Summer
3-Way Split
Condenser Valve
Compressor
Receiver
W
Q
Check
Valve
A8 Pressure
Regulating Valve
A9 Hot Gas
Bypass Regulator
E
Figure 6
Q Pilot suction line must be open to common suction
regardless of Split Condenser Valve model/type.
W Proper support of the Split Condenser Valves,
especially the larger models, is essential because
of possible vibrations of the piping and/or their
location on the compressor racks. (For example, a
bracket located 2-3” from the 16D Discharge and
Condenser B socket solder joints is recommended.)
E Restrictor, part no. 2449-004, may be used to con-
trol pump out rate on inactive condenser.
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