Carrier 19XL Chiller Dehydration , InspectWater Piping , CheckOptional Pumpout Compressor Water Pip- ing , Check Relief Devices , Inspect Wiring

Chiller Dehydration — Dehydration is recommended

ifthe chiller has been open for a considerable period of time,

if the chiller is known to contain moisture, or if there has

been a complete loss of chiller holding chargeor refrigerant

pressure.

Do not start or megohm test the compressor motor or

oil pump motor, even for a rotation check, if the chiller

isunder dehydration vacuum. Insulation breakdown and

severe damage may result.

Dehydration is readily accomplished at room tempera-

tures. Use of a cold trap (Fig. 29) may substantially reduce

the time required to complete the dehydration. The higher

the room temperature, the faster dehydration takes place.At

low room temperatures, a very deep vacuum is required for

boiling off any moisture. If low ambient temperatures are

involved, contact a qualiﬁed service representative for the

dehydration techniques required.

Perform dehydration as follows:

1. Connect a high capacity vacuum pump (5 cfm

[.002 m

/s] or larger is recommended) to the refrigerant

chargingvalve (Fig. 2A or 2B). Tubing from the pump to

the chiller should be as short and as large a diameter as

possible to provide least resistance to gas ﬂow.

2. Usean absolute pressure manometer or a wet bulb vacuum

indicator to measure the vacuum. Open the shutoffvalve

tothe vacuum indicator only when taking a reading. Leave

thevalve open for 3 minutes to allow the indicator vacuum

to equalize with the chiller vacuum.

3. Open all isolation valves (if present), if the entire chiller

is to be dehydrated.

4. With the chiller ambient temperature at 60 F (15.6 C) or

higher,operate the vacuum pump until the manometer reads

29.8 in. Hg vac, ref 30 in. bar. (0.1 psia) (–100.61 kPa)

or a vacuum indicator reads 35 F (1.7 C). Operate the

pump an additional 2 hours.

Do not apply greater vacuum than 29.82 in. Hg vac

(757.4mm Hg) or go below 33 F (.56 C) on the wet bulb

vacuum indicator.At this temperature/pressure, isolated

pockets of moisture can turn into ice. The slow rate of

evaporation(sublimination) of ice at these low temperatures/

pressures greatly increases dehydration time.

5. Valve off the vacuum pump, stop the pump, and record

the instrument reading.

6. After a 2-hour wait, take another instrument reading. If

the reading has not changed, dehydration is complete. If

the reading indicates vacuum loss, repeat Steps 4 and 5.

7. If the reading continues to change after several attempts,

perform a leak test up to the maximum 230 psig

(1585 kPa) pressure. Locate and repair the leak, and re-

peat dehydration.

InspectWater Piping — Refer to piping diagrams pro-

vided in the certiﬁed drawings, and the piping instructions

in the 19XL Installation Instructions manual. Inspect the

piping to the cooler and condenser.Be sure that ﬂow direc-

tions are correct and that all piping speciﬁcations have been

met.

Pipingsystems must be properly vented, with no stress on

waterboxnozzles and covers. Water ﬂows through the cooler

andcondenser must meet job requirements. Measure the pres-

sure drop across cooler and across condenser.

Water must be within design limits, clean, and treated

to ensure proper chiller performance and reduce the

potential of tubing damage due to corrosion, scaling, or

erosion.Carrier assumes no responsibility for chiller dam-

age resulting from untreated or improperly treated

water.

CheckOptional Pumpout Compressor Water Pip-

ing — If the optional storage tank and/or pumpout system

are installed, check to ensure the pumpout condenser water

has been piped in. Check for ﬁeld-supplied shutoff valves

and controls as speciﬁed in the job data. Check for refrig-

erant leaks on ﬁeld-installed piping. See Fig. 27 and 28.

Check Relief Devices — Be sure that relief devices

have been piped to the outdoors in compliance with the lat-

est edition of ANSI/ASHRAE Standard 15 and applicable

localsafety codes. Piping connections must allow for access

to the valve mechanism for periodic inspection and leak

testing.

19XL relief valves are set to relieve at the 300 psig

(2068 kPa) chiller design pressure.

Inspect Wiring

Do not check voltage supply without proper equipment

andprecautions. Serious injury may result. Follow power

company recommendations.

Do not apply any kind of test voltage, even for a rota-

tioncheck, if the chiller is under a dehydration vacuum.

Insulation breakdown and serious damage may result.

1. Examine wiring for conformance to job wiring dia-

grams and to all applicable electrical codes.

2. On low-voltage compressors (600 v or less) connect

voltmeter across the power wires to the compressor

starter and measure the voltage. Compare this reading

with the voltage rating on the compressor and starter

nameplates.

3. Comparethe ampere rating on the starter nameplate with

thecompressor nameplate. The overload trip amps must

be 108% to 120% of the rated load amps.

4. Thestarter for a centrifugal compressor motor must con-

tain the components and terminals required for PIC

refrigeration control. Check certiﬁed drawings.

5. Check the voltage to the following components and

compare to the nameplate values: oil pump contact,

pumpout compressor starter, and power panel.

Fig. 29 — Dehydration Cold Trap