York E3GE036S01B, Руководство по установке

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The defrost control will initiate defrost more frequently at higher
ambient temperatures (higher moisture content) and less fre-
quently at lower ambient temperatures (lower moisture content).
The defrost control (part of the YORK controller) is factory set
to initiate defrost at 90 minutes (pin T-3) with 35
°
F ambient
temperature. The control can be reset in the field to 50 (pin T-1) or
70 (pin T-2) minutes. Refer to Figure 17.
Figure 16 shows the time variation with various outdoor tem-
peratures for each of the three settings. For example, if the
timer is factory set on pin T-3 or 90 minutes (at 35
°
F outdoor)
and the outdoor temperature should climb to 43
°
F, the time
initiation cycle will decrease to approximately every 82 minutes
(broken line).
Should the outdoor temperature should drop to 10
°
F where ice
is less likely to form, the 90 minute interval would now extend
to approximately every 125 minutes (solid line).
The defrost times will get longer as the engine speed is reduced.
The system control will constantly update the defrost time based
on the present speed. To determine the exact defrost time, the
analyzer will read out the expected time continuously.
For example, at the T3 setting with the outdoor ambient at 35
°
F,
the defrost time would increase from 90 minutes to 135 minutes
when the engine speed is reduced to 2000 rpm.
Defrost Operation
During normal heating operation frost and ice will form on the
outdoor unit coil, requiring a defrost cycle. Due to the arrange-
ment of the coil circuits, frost may accumulate unevenly on the
coil and the unit may enter a defrost even though the center
section is not frosted.
Defrost will occur when:
•
The ambient is below 43
°
F.
•
The liquid line temperature is below 35
°
F.
The defrost schedule will occur based on time of operation and
engine speed, and is calculated every five minutes to determine
the need for defrost.
When the unit goes into defrost cycle, the following will occur:
1. The indoor blower will ramp to full speed.
2. The electric heater will be turned on.
3. The engine speed will be reduced to 1500 RPM.
4. After 30 seconds, the reversing valve will shift.
5. The outdoor fan will cycle on and off.
6. The engine speed will then increase to 3000 RPM for the
duration of the defrost cycle.
7. The electric heater or add-on hot water hydronic system
will operate during the defrost cycle to temper the indoor
supply air.
The defrost will terminate when:
1. The liquid temperature has reached 75
°
F, or
2. The liquid temperature has reached 45
°
F for two minutes or,
3. The defrost cycle has been active for 15 minutes.
At end of defrost, the engine speed will reduce to 1500 RPM,
the reversing valve will shift and the outdoor fan will start.
The system will then return to the required speed based on the
previous thermostat demand.
FAILURE - FAULT CODES
The unit control will monitor system operation and will respond
to a fault codes by one of three methods:
•
Lockout the unit
•
Shutdown the engine but allow an automatic restart
•
Record a fault code but not effect the operation of the unit.
The service analyzer will identify the fault. A secondary method
is the indicator light on the unit control which identifies the fault
by flashing a two-digit code.
The first digit is indicated by the number of flashes and is
followed by a three second pause; the second digit is then
indicated by the same process and is followed by a five second
pause. This will repeat continuously.
The engine control will also flash in a like manner, but does not
contain all the codes and is used only for reference.
Fault codes are listed below:
Unit lockout codes -
11 - HPCO or engine gas valve fault
12 - Engine overspeed
13 - Engine oil level low
14 - Engine oil pressure low
15 - Excessive system starts
16 - Multiple engine faults
55 - Low pressure cutout open
61 - System control failure
Unit shutdown codes, but restart allowed after fault clears -
21 - Engine start up fault
22 - Coolant over-temperature
23 - Coolant sensor failure
24 - Oil press switch failure
25 - ECS communications error
26 - ECS electronics failure
27 - Underspeed/stall fault
28 - 12 volt power fault
44 - Invalid t’stat outputs
51 - Liq. line temp sensor fail
54 - 24 vac power low
57 - ECS interfacel error
FIGURE 17 - DEFROST CONTROL OPTIONS
NOTE: The defrost cycle can be manually invoked by
the service analyzer.
515.35-N6Y
12 Unitary Products Group