Carrier XRV Spécifications télécharger pdf (Page 77)

Use the CONTROL TEST terminate lockout function to

monitor conditions and start the pumps.

If the chiller has been shipped with a holding charge

, the

refrigerant is added through the pumpout charging connection

(Fig. 30 and 31, valve 1b). First evacuate the nitrogen holding

charge from the chiller vessels. Charge the refrigerant as a gas

until the system pressure exceeds 35 psig (141 kPa) for

HFC-134a. After the chiller is beyond this pressure the refrig-

erant should be charged as a liquid until all the recommended

refrigerant charge has been added. The charging valve (Fig. 30

and 31, valve 1a or 1b) can be used to charge liquid to the cool-

er or condenser. Do not charge liquid through the liquid line

service valve.

TRIMMING REFRIGERANT CHARGE — The 19XRV unit

is shipped with the correct charge for the design duty of the

chiller. On most 19XRV chillers the design LTD (Leaving

Temperature Difference) between the leaving chilled water

temperature and the cooler refrigerant temperature is so low

that the traditional method of trimming the charge to achieve a

minimum LTD is not practical. In the case where leaks have

been found and corrected and the LTD is greater than about 4 F

(2.2 C) above design, add refrigerant until the full load design

LTD is approached, and then charge for proper oil return at low

load. (A high cooler LTD can also be caused by dirty tubes,

water box division plate bypass, a partially closed liquid isola-

tion valve, or a sticking float valve.)

If low load oil loss is experienced, operate the chiller at low

load with the guide vanes nearly closed and observe the flow

through the sight glass in the oil skimmer line. Under low load

operation one should be able to see a flow of bubbly oil and

refrigerant in the sight glass. If there is no visible flow, add

refrigerant. If the sight glass shows a flow of nearly clear fluid,

remove refrigerant.

The preferred location at which refrigerant should be added

directly into the chiller is through the service valve at the top of

the condenser. If that valve is not accessible due to presence of

an attached pumpdown unit which does not have a storage

tank, add charge through the valve connected to the side of the

condenser drain float sump. Adding charge through the drain

valve at the base of the chiller (off the liquid line) is NOT

recommended.

The full refrigerant charge on the 19XRV chiller will vary

with chiller components and design conditions, as indicated on

the job data specifications. An approximate charge may be de-

termined by adding the condenser charge to the cooler charge

as listed in Tables 14A and 14B.

INITIAL START-UP

Preparation —

Before starting the chiller, verify:

1. Power is on to the VFD, oil pump relay, oil heater relay,

and the chiller control panel.

2. Cooling tower water is at proper level and at-or-below

design entering temperature.

3. Chiller is charged with refrigerant and all refrigerant and

oil valves are in their proper operating positions.

4. Oil is at the proper level in the reservoir sight glasses.

5. Oil reservoir temperature is above 140 F (60 C) or above

refrigerant temperature plus 50 F (28 C).

6. Valves in the evaporator and condenser water circuits are

open.

NOTE: If the pumps are not automatic, ensure water is

circulating properly.

7. Access the CONTROL TEST screen. Scroll down on the

TERMINATE LOCKOUT option. Press the SELECT (to

enable the chiller to start) and answer YES to reset unit to

operating mode. The chiller is locked out at the factory in

order to prevent accidental start-up.

Check Motor Rotation

1. Engage the control power circuit breaker (CB2) located

inside the left hand side of the VFD enclosure.

2. Finally close the main motor disconnect (CB1) on the

front of the VFD enclosure.

3. The VFD checks for proper phase rotation as soon as

power is applied to the VFD and the PIC III controls

power up. The controls do not permit a start if the phase

rotation is not correct.

4. An alarm message will appear on the ICVC if the phase

rotation is incorrect. If this occurs, reverse any 2 of the 3

incoming power leads to the VFD and reapply power.

The motor is now ready for a rotation check.

5. After the default screen status message states ‘Ready to

Start’ press the softkey. The PIC III control

performs start-up checks.

6. When the VFD is energized and the motor begins to turn,

check for clockwise motor rotation. See Fig. 41.

CAUTION

Ensure that the condenser and chilled water pumps are

operating whenever charging, transferring, or removing

refrigerant from the chiller. Failure to do so could result in

serious personal injury or equipment damage.

IMPORTANT: The Reliance VFD warranty will be void if

the VFD is not started by a technician who has completed

Reliance LiquiFlo™ Tier 1 Training and whose name is

registered with Reliance.

CAUTION

Do not permit water or brine that is warmer than 110 F

(43 C) to flow through the cooler or condenser. Refrigerant

overpressure may discharge through the relief valves and

result in the loss of refrigerant charge, damaging the chiller.

CAUTION

Do not check motor rotation during coastdown. Rotation

may have reversed during equalization of vessel pressures.

LOCAL

Fig. 41 — Correct Motor Rotation

a19-1326

1 2 ... 72 73 74 75 76 77 78 79 80 81 82 ... 189 190

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Carrier XRV Spécifications Page 77

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