York YCAZ33BA3, Руководство пользователя, Страница: 76 / 88

YORK INTERNATIONAL
76
RWT Control Hot Gas Operation
The hot gas solenoid is energized if the compressor is
on its minimum stage of loading and the return water
temperature falls below the following point:
ULCR - CR + CR/20
Where: ULCR = Upper Limit of Control Range
CR = Control Range Differential
Example:
In a typical system that requires a 45°F leaving water
temperature, we will have a 10° Control Range (CR)
differential which gives us an Upper Limit of Control
Range (ULCR) of 55°F. Therefore, plugging the num-
bers into the formula:
55 - 10 + (10/20) = 45-1/2°F
The hot gas solenoid will be activated at 45-1/2°F in the
example above and hot gas may then be fed according
to the suction pressure and the pressure regulated valve
setting. Once activated, the micro will keep the solenoid
energized until the return water temperature rises above
the temperature designated by the formula:
ULCR - CR + CR/10
Where: ULCR = Upper Limit of Control Range
CR = Control Range Differential
Example: 55 - 10 + 10/10 = 46°F
If temperature continues to drop while the Hot Gas is
energized, the Hot Gas will be de-energized when the
compressor cycles off on temperature.
Procedure For Setting The Hot Gas Regulators
(Ref. Fig. 29)
1. If desired, set the control panel data to show suction
pressure.
2. Adjust the pilot power assembly adjustment screw
2 to approximately the middle of the adjustment
range.
3. The chiller must be running and stabilized on the
minimum stage capacity. In establishing this condi-
tion it may be necessary to deactivate the regulator
by de-energizing the solenoid 1 .
4. Adjust the adjustment screw 2 in the clockwise
direction to open the valve at a higher pressure
(sooner) or in the counterclockwise direction to open
the valve at a lower pressure (slower response). The
valve is feeding when the valve outlet feels warm to
the touch.
The adjustment is correct when system suction pres-
sure rises to a point nearly equal to normal running
pressure at the midpoint in the “Control Zone”.
5. Further minor adjustment may be necessary to be
certain that the valve opens fully before the tempera-
ture point at which the compressor stops due to a
fall in Return or Leaving Water Temp.
6. Repeat this procedure on the other system.
FIELD INSTALLATION
If it becomes necessary to field install the Hot Gas
(Loadminder) Option, two kits are required. The part
numbers of the kits are 375-05648-001 and 471-01232-
101. The 475-01232-101 kit consists of a second Re-
lay Output Board. It is not required if two Relay Boards
are already installed in the control panel. If the 375-
05648-001 kit is not available, the following parts should
be ordered separately.
FIG. 29 – PIPING DIAGRAM
LD02010
ITEM QTY PART # DESCRIPTION
1 1 375-00223-012 SOL. VALVE
2 1 066-94986-000 BRACKET
3 3 021-16129-000 SCREW
4 2 066-84635-000 CLAMP
5 1 066-65196-000 CLAMP
6 1 066-38928-000 CLAMP
7 1 066-94250-000 PIPE CONN.
8 4 023-09919-000 REDUCER
9 1 075-05635-000 PIPE CONN.
10 1 066-93940-000 PIPE CONN.
11 1 075-05637-000 BRACKET
12 8 012-16207-000 SCREW
13 2 021-11452-000 CLAMP
15 2 021-16203-000 SCREW
16 1 021-13245-000 CLAMP
19 2 031-01117-000 SUPPRESSOR
22 1 375-00223-013 SOL. VALVE
23 1 075-05841-000 PIPE CONN.
24 1 075-05638-000 PIPE CONN.
25 1 075-05639-000 PIPE CONN.
XX 1 075-05648-000 DRAWING
Parts List