York YCAS0295EB, Installation Operation & Maintenance

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170 YORK INTERNATIONAL
FORM 201.19-NM7 (804)
8.7 EEV TROUBLESHOOTING
TROUBLESHOOTING
Below are problems and possible so lu tions or items
to check.
●
The system shuts down on Low Suction
Pres sure
· Verify that all refrigerant valves are open.
· Verify that the system is not low on charge.
· Verify that the Expansion Valve Type is set to Elec-
tron ic.
· Verify that the pilot solenoid is energizing (use Service
Mode to manually energize the so le noid coil).
· Verify that the EEV is wired per the elementary dia-
gram.
· Verify that the Heat Motor is getting a 24VAC PWM
signal. (Use Service Mode to manually en er gize
the EEV output.
· If everything checks out, it is possible that the EEV
has failed. If the small charge in the bulb leaks, the
valve will not be able to open and the entire EEV
must be replaced.
●
The system shuts down on Low Su per heat
· Verify that the suction temperature sensors are properly
installed. They should be located at 4 or 8 o’clock
on the suc tion line. They should not be located near
the out let of the evaporator. They should be installed
with cop per straps and be well insulated.
· Verify that the suction temperature sensor ca bles are
not swapped between systems (un plug ging one sen-
sor at a time with the chiller off can ver i fy prop er
wiring).
· Verify that the EEV heat motor is properly in su lat ed.
· For units with Hot Gas Bypass installed, check that the
Hot Gas Bypass valve is set correctly.
· For glycol units, verify that the glycol % is cor rect.
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