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Low ambient control, option be8, Temperature to resistance table – Reznor YDSA Operation Manual User Manual

Page 15

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Form O-Y P/N 273647R1, Page 15

FIGURE 16 - Cooling Circuit B with Optional Bypass Valve (Option AUC8)

Model YDHA 120 and 150 (Cabinet 1) with Option AUC8
Model YDMA 120 and 150 (Cabinet 1) with Option AUC8
Model YDSA 120 and 150 (Cabinet 2) with Option AUC8
Model YDHA 180, 210, and 240 (Cabinet 2) with Option AUC8
Model YDMA 180, 210, and 240 (Cabinet 2) with Option AUC8
Model YDSA 180 and 210 (Cabinet 3) with Option AUC8
Model YDHA 300 and 360 (Cabinet 3) with Option AUC8
Model YDMA 300 and 360 (Cabinet 3) with Option AUC8

Circuit B with Optional Hot Gas Bypass

Hot Gas Bypass Check Valve at the Evaporator Coil

Condenser Coil

Circuit B

Condenser Coil

Circuit A

View from Compressor and

Condenser Section

Hot Gas

Bypass Valve

Modulating

Compressor

(Circuit A)

Compressor

(Circuit B)

Compressor

(Optional Circuit DH)

Shutoff

Valve

Condenser

Coil - Circuit B

Hot Gas

Bypass Valve

Shutoff

Valve

Equalizer

Tube

Low Ambient Control,

Option BE8

If equipped with low ambient control, cooling is allowed to operate with an outside air tempera-

ture as low as 35°F (1.7°C).

Low Ambient Control for standard condenser fans (Option BE8

with Fan Option CUF3)

The electronic head pressure control modulates condenser fan motor speed in

low temperatures, varying the air volume through the condenser to regulate head

pressure. This model’s dual sensor input allows for the control of one or two

independent refrigerant circuits sharing the same fan motor(s). Only open, drip

proof, PSC or Shaded Pole motors are applicable for motor speed regulation. The

Controller monitors the liquid line temperature(degrees of excessive sub-cooling)

which is directly proportional to the head pressure. Speed modulation begins at 80°F

liquid line and proportionally reduces the fan to minimum speed once the liquid line

temperature reaches 50°F. Motor is turned off at liquid temperatures below or equal to

50°F. At 53°F the fan restarts at full speed; then modulates to minimum speed. When

the liquid temperature is 50°F and below the condenser fan motor will cycle between

minimum RPM and off to maintain proper condenser temperature (head pressure).

The above describes a 30ºF span (80ºF to 50ºF) function; a 25ºF span is also

available. The 25ºF span is recommended for High Efficiency systems; 30ºF span for

typical systems. Variable condenser airflow is modulated from full to minimum speed

over the selected span.

Option BE Pressure

Controller with Fan

Option CUF3,

P/N 261041

Use Temperature

to Resistance table

shown on right to

verify proper sensor

operation.

Temperature to

Resistance Table

This manual is related to the following products: