Table 6-1 — Troubleshooting EPR Valves
KOOLGAS VALVES
Koolgas valving is piped in one of two ways.
With a stop suction EPR, a simple 2-way solenoid
valve is used. Without, a 3-way solenoid valve is
used. Unless there is damage to the valve body
itself, both the 2-way and 3-way valve may be
disassembled and repaired in the field.
CONTROL VALVES
September 1, 1997
6 - 2
HUSSM ANN CORPORATION • BRIDGETON, M O 63044-2483 • Printed in USA
Figure 6-2 — Koolgas Valve Piping
Malfunction
Cause
Action
Fails to Open
Dirt holding pilot port open
Disassemble and clean
Solenoid not energized
-bad solenoid
Replace solenoid
-circuit open
find and repair open
-stuck in defrost mode
correct defrost clock problem
Fails to close
High pressure inlet strainer plugged
Clean or replace
High pressure line pinched, shut off
Clean or replace. If oil filled, re-pipe
or plugged
so high pressure line is not an oil trap
Sleeve or piston scored, allowing
Replace
high pressure leak from piston
chamber
Dirt in piston chamber, causing drag
Clean or replace
High pressure supply lower than
defrost vapor pressure
Re-pipe
(Sporlan) Faulty T-seal or Gasket
Replace
Does not
Low high pressure supply, 50 psig
Increase pressure supply
Regulate
or more required in differential between
Temperature
high pressure and down stream suction
Condensation in long high pressure line
Insulate and/or relocate to higher pressure
source
KS
EPR
KS
To Evaporator
From Koolgas
Manifold
To Suction
Manifold
To Suction
Manifold
To Evaporator
From Koolgas
Manifold
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