Carrier VECTOR 1800 MT - Figure 2-5. Compressor Cylinder Head Unloaded

2-8
62-11039
1
23
4
5
6
7
8
9
10
11
12
13
14
15
1. Solenoid Valve
2. Valve Stem
3. Gas Bypass Port
4. Spring Guide
5. Spring
6. Piston
7. Piston Bypass Valve
8. Bleed Orifice
9. Strainer
10. Suction Manifold
11. Cylinder Discharge Valve
12. Valve Plate
13. Cylinder Suction Valve
14. Discharge Piston Check Valve Assembly
15. Discharge Manifold
Figure 2-5. Compressor Cylinder Head Unloaded
b. Unloaded Operation
Pressure from the discharge manifold (Figure 2-5, item
15) passes through the strainer (9) and bleed orifice (8)
to the back of the piston bypass valve (7). Unless bled
away, this pressure would tend to close the piston (6)
against the piston spring (5) pressure.
With the solenoid valve (1) energized the solenoid valve
stem (2) will open the gas bypass port (3).
Refrigerant pressure will be bled to the suction manifold
(10) through the opened gas bypass port . A reduction in
pressure on the piston bypass valve will take place
because the rate of bleed through the gas bypass port is
greater than the rate of bleed through the bleed orifice (8).
When the pressure behind the piston has been reduced
sufficiently, the valve spring will force the piston bypass
valve back, opening the gas bypass from the discharge
manifold to the suction manifold.
Discharge pressure in the discharge manifold will close
the discharge piston check valve assembly (14)
isolating the compressor discharge manifold from the
individual cylinder bank manifold.
The unloaded cylinder bank will continue to operate fully
unloaded until the solenoid valve control device is
de-energized and the gas bypass port is closed.