Wells RW-16 thru RW-36 Manuel d'installation télécharger pdf (Page 21)

RW SERIES INSTALLATION MANUAL

AntiShortCycle

HighPressureProtection

LowPressureProtection

AdvancedFreezeDetectionSetpoint

RandomStart

Displayfordiagnostics

ResetLockoutatdisconnect

Intelligentresetforfieldinstalledflowswitches

1Accessoryoutput

OptionalDDCcontroladd-on

CompressorLead/Lag

CompressorCurrentSwitches

FieldSelectableOptions

FreezeDetectionSensingSelect(DI-4andDI-5)

The freeze detection temperature sensing selection inputs allow

the user to adjust the setpoints. The source sensors are wired to

inputs AI-3 and AI-4 while the load sensors are wired to inputs AI-5

and AI-6. The setpoints for both, the load and source, are factory

set for 30°F. In order to change the setpoint to 15°F on the source,

remove the jumper wire from DI-4 (wire #56). The load setpoint can

be changed by removing the jumper wire from DI-5 (wire #55).

AccessoryOutput(DO-4)

The accessory Output will be energized 90 seconds prior to

the lead compressor output being energized. When the lead

compressor output is turned off the accessory output will be

deactivated immediately. The output is selectable for normally

open or normally closed operation through the unit mounted user

interface or from a building automation system.

ControlandSafetyFeatures

EmergencyShutdown

The emergency shutdown mode can be activated by a command

from a facility management system or a closed contact on DI-

2. The default state for the emergency shutdown data point is off.

When the emergency shutdown mode is activated, all outputs will

be turned off immediately and will remain off until the emergency

shutdown mode is de-activated. The first time the compressor

starts after the emergency shutdown mode has been de-activated,

there will be a random start delay present.

LockoutMode

Lockout mode can be activated by any of the following fault signals:

refrigerant system high pressure, refrigerant system low pressure,

heating freeze detection, cooling freeze detection, and compressor

current sensor. When any valid fault signal remains continuously

active for the length of its recognition delay, the controller will

go into fault retry mode, which will turn off the compressor. After

the Compressor short cycle delay, the compressor will attempt

to operate once again. If three consecutive faults are recognized

during a single heating or cooling demand, the unit will go into

lockout mode, turning off the compressor and enabling the alarm

Control Features

output until the controller is reset. The fault count will automatically

reset when the heating or cooling command becomes satisfied. If

a fault occurs on a dual compressor unit, the other compressor will

continue to operate based on the heating or cooling demand. The

lockout condition can be reset by powering down the controller, by

a command from the facility management system, or by holding

both the enter and escape keys on the optional user interface.

ReversibleChillerAdvancedFreeze

DetectionSystem

The reversible chiller source and load heat exchangers are protected

by a multi-sourced temperature logic strategy. The temperature logic

is based upon the refrigerant temperature sensed as the refrigerant

is about to enter the heat exchanger; while entering and leaving

water temperatures are being used as correlating factors. The

detection scheme is shown as basic and advanced algorithms.

BasicFreezeDetectionOperation:“Comp1orComp2

Freeze”Alarm

This alarm can be triggered by one of two detection schemes.

HardLimitFreezeDetection

If the refrigerant temperature drops below the freeze detection

setpoint by 1.8°F, the associated compressor is locked out

immediately regardless of any other factors and requires a

manual reset. NOTE:ThisLockoutproducesa“Comp1or

Comp2Freeze”errorontheMUIdisplay.

FreezeDetection

The refrigerant temperature is compared to the freeze detection

setpoint (15°F [antifreeze] or 33°F [water] field selectable), and

if the temperature falls below the setpoint for 30 continuous

seconds, the associated compressor will be halted. This

function becomes enabled after the first two minutes of

compressor operation. Three such events in 60 minutes will

trigger a compressor lockout that requires a manual reset.

NOTE:ThisLockoutproducesa“Comp1orComp2

Freeze”errorontheMUIdisplay.

Inadditiontotheabove:

Entering Water Temperature Influence

If the entering water temperature of the evaporative heat

exchanger is within 10°F of the freeze setpoint, the previously

mentioned two minute delay will be eliminated. This allows the

freeze detection to operate immediately when the compressor

starts based on entering water temperature.

Leaving Water Temperature Influence

If the leaving water temperature of the evaporative heat

exchanger is within 10°F of the freeze setpoint, the previously

mentioned 30 second delay will begin to be proportionately

reduced, ending at a 1 second delay when the leaving water

temperature is 1.5°F above the freeze setpoint.

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Wells RW-16 thru RW-36 Manuel d'installation Page 21

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