Wells RW-16 thru RW-36 Manuel d'installation télécharger pdf (Page 23)

RW SERIES INSTALLATION MANUAL

PowerFailRestart

When the controller is first powered up, the outputs will be

disabled for a random start delay time (See Section 4.2). The

delay is provided to prevent simultaneous starting of multiple heat

pumps. Once the timer expires, the controller will operate in the

occupied mode until it is commanded to another mode by a facility

management system or a remote thermostat. A restart status

variable is available for indication of this occurrence.

RandomStartDelay

This delay will be used after every power failure, as well as the

first time the compressor(s) is started after the control exits the

emergency shutdown mode. The default time period for the start

delay will be random between 1 and 120 seconds.

CompressorFixedOnDelayTime

The Compressor Fixed On Delay Time will ensure that the

compressor output is not enabled for (90) seconds after the control

receives a call to start the compressor.

CompressorMinimumOnDelay

The compressor minimum on delay will ensure that the compressor

output(s) are enabled for a minimum of (2) minute each time

the compressor output is enabled. This will apply in every

instance except in the event the high-pressure switch is tripped or

emergency shutdown, then the compressor output will be disabled

immediately.

CompressorShortCycleDelayTime

The compressor short cycle time delay will ensure that the

compressor output will not be enabled for a minimum of (5) minutes

after it is disabled. This allows for the system refrigerant pressures

to equalize after the compressor is disabled.

CompressorStageLeadLag

The factory setup software, a facility management system, Service/

Commissioning Tool, or a user interface can be used to select

compressor lead lag option for the compressors. The factory setup

software, a facility management system, Service/Commissioning

Tool, or a user interface must also be used to select the number

of run time hours the compressors will lead before being switched,

the factory default will be 24 hours. The two compressors will still

be staged depending on load when the lead lag option is enabled.

Sequence of Operation

HeatingCycle

During the heating cycle, the reversing valves will be positioned

for heating operation. The thermostat or aquastat will command

the reversing valves “On” for heating. If the compressor short

cycle time delay has been satisfied, the lead compressor will turn

on after the accessory output has been enabled, the low pressure

switches has been verified, and the fixed compressor start delay

timer has been satisfied. When heating is no longer required, the

compressor will be turned off immediately after the compressor

minimum on delay has been satisfied. After the compressor

output is turned off, it will remain off for the time specified in the

compressor short cycle time delay. If the dual compressor option

is selected, the compressors will be sequenced to maintain the

heating setpoint. As the temperature drops below the heating

setpoint and begins to operate in the heating proportional band,

the first stage compressor will be activated. If the first stage

compressor is not able to satisfy the heating demand, the second

stage compressor will be activated by the thermostat or aquastat.

The controller is allowed to operate the heat pump in the heating

mode regardless of the outdoor air temperature.

CoolingCycle

During the cooling cycle, the reversing valves will be positioned for

cooling operation. The thermostat or aquastat will command the

reversing valves “Off” for cooling. If the compressor short cycle

time delay has been satisfied, the lead compressor will turn on after

the accessory output has been enabled, the low pressure switches

has been verified, and the fixed compressor start delay timer has

been satisfied. When cooling is no longer required, the compressor

will be turned off immediately after the compressor minimum on

delay has been satisfied. After the compressor output is turned

off, it will remain off for the time specified in the compressor short

cycle time delay. If the dual compressor option is selected, the

compressors will be sequenced to maintain the cooling setpoint.

As the temperature drops below the cooling setpoint and begins to

operate in the cooling proportional band, the first stage compressor

will be activated. If the first stage compressor is not able to satisfy

the cooling demand, the second stage compressor will be activated

by the thermostat or aquastat. The controller is allowed to operate

the heat pump in the cooling mode regardless of the outdoor air

temperature.

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Wells RW-16 thru RW-36 Manuel d'installation Page 23

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Produits connexes et manuels pour Réchauffeurs de nourriture Wells RW-16 thru RW-36