Chiller Dehydration; Inspect Water Piping; Check Optional Pumpout Compressor; Water Piping - Carrier 19XR Start-Up, Operation And Maintenance Instructions Manual

Chiller Dehydration —
if the 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 charge or refrigerant
pressure.
Do not start or megohm-test the compressor motor or
oil pump motor, even for a rotation check, if the chiller
is under dehydration vacuum. Insulation breakdown and
severe damage may result.
Inside-delta type starters must be disconnected by an iso-
lation switch before placing the machine under a vacuum
because one lead of each phase is live with respect to
ground even though there is not a complete circuit to
run the motor. To be safe, isolate any starter before evacu-
ating the chiller if you are not sure if there are live leads
to the hermetic motor.
Dehydration can be done at room temperatures. Using a
cold trap (Fig. 28) may substantially reduce the time re-
quired to complete the dehydration. The higher the room tem-
perature, the faster dehydration takes place. At low room
temperatures, a very deep vacuum is required to boil off any
moisture. If low ambient temperatures are involved, contact
a qualified service representative for the dehydration tech-
niques required.
Perform dehydration as follows:
1. Connect a high capacity vacuum pump (5 cfm [.002 m
or larger is recommended) to the refrigerant charging valve
(Fig. 2). Tubing from the pump to the chiller should be
as short in length and as large in diameter as possible to
provide least resistance to gas flow.
2. Use an absolute pressure manometer or a wet bulb vacuum
indicator to measure the vacuum. Open the shutoff valve
to the vacuum indicator only when taking a reading. Leave
the valve open for 3 minutes to allow the indicator vacuum
to equalize with the chiller vacuum.
3. If the entire chiller is to be dehydrated, open all isolation
valves (if present).
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 a greater vacuum than 29.82 in. Hg vac
(757.4 mm Hg) or go below 33 F (.56 C) on the wet bulb
vacuum indicator. At this temperature and pressure, iso-
lated pockets of moisture can turn into ice. The slow rate
of evaporation (sublimation) of ice at these low tempera-
tures and 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 160 psig
(1103 kPa) pressure. Locate and repair the leak, and re-
peat dehydration.
Dehydration is recommended
3
/s]
Fig. 28 — Dehydration Cold Trap
Inspect Water Piping —
vided in the certified drawings and the piping instructions
in the 19XR Installation Instructions manual. Inspect the pip-
ing to the cooler and condenser. Be sure that the flow
directions are correct and that all piping specifications have
been met.
Piping systems must be properly vented with no stress on
waterbox nozzles and covers. Water flows through the cooler
and condenser must meet job requirements. Measure the pres-
sure drop across the cooler and the condenser.
Water must be within design limits, clean, and treated
to ensure proper chiller performance and to reduce the
potential of tube damage due to corrosion, scaling, or
erosion. Carrier assumes no responsibility for chiller
damage resulting from untreated or improperly treated
water.
Check Optional Pumpout Compressor Water
Piping —
If the optional pumpout 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 refrigerant leaks on field-installed piping.
See Fig. 26 and 27.
Check Relief Valves —
been piped to the outdoors in compliance with the
latest edition of ANSI/ASHRAE Standard 15 and applicable
local safety codes. Piping connections must allow for access
to the valve mechanism for periodic inspection and leak
testing.
The 19XR relief valves are set to relieve at the 185 psig
(1275 kPa) chiller design pressure.

Inspect Wiring

Do not check the voltage supply without proper equip-
ment and precautions. Serious injury may result. Fol-
low power company recommendations.
Do not apply any kind of test voltage, even for a rota-
tion check, if the chiller is under a dehydration vacuum.
Insulation breakdown and serious damage may result.
1. Examine the wiring for conformance to the job wiring
diagrams and all applicable electrical codes.
51
Refer to piping diagrams pro-
Be sure the relief valves have