Hussmann Scroll Plus Fibertronic 401789 Installation And Service Manual page 82

September 1, 1997
From Koolgas
Manifold
Figure 6-3 — 2-Way Solenoid Valve
Both the EPR and the 2-way solenoid valves are
normally closed, so the EPR must be powered
only during refrigeration and the 2-way valve
only during defrost.
The 3-way valve is normally in refrigeration
mode. Energizing the solenoid opens the pilot
valve port which directs high pressure Koolgas
vapor to the piston chamber. Pushed to its
opposite position, the piston assembly stops the
suction line and opens the Koolgas line. A bleed
port in the piston provides for de-compression of
the piston chamber when the pilot port closes.
Table 6-2 — Troubleshooting Koolgas Valves
Malfunction Cause
Fails to Open Dirt plugging pilot port
Solenoid not energized
-bad solenoid
-circuit open
-NOT in defrost mode
Fails to close Piston port plugged
Barrel or piston scored
Dirt in piston chamber, causing drag
Stuck in defrost mode
Return to Contents
To Evaporator
To Evaporator
Refrigeration
Figure 6-4 — 3-Way Solenoid Valve
Action
Disassemble and clean
Replace solenoid
Find and repair open
Correct defrost clock problem
Clean or replace
Replace
Clean or replace
Correct defrost clock problem
HUSSM ANN CORPORATION • BRIDGETON, M O 63044-2483 • Printed in USA
Defrost
P/N 401789
6 - 3
From Koolgas
Manifold
To Suction
Manifold