10
Table 3 — Liquid Line Refrigerant Chart
Table 4 — Double Discharge Riser Data
The 30MPA units that use air-cooled or evaporative con-
densers must have adequate means for head pressure control
when operating below 60 F (15.6 C) ambient.
The 30MPA remote condenser requirements are as follows:
• If multiple units are connected to a single condenser,
ensure each refrigerant circuit has its own head pressure
control.
• Condenser must provide 15 F (8.3 C) subcooling, maxi-
mum of 40 F (22.2 C) difference between saturated con-
densing temperature and outdoor ambient temperature
(to prevent overload at high ambient temperatures), and
a minimum of 20 F (11.1 C) difference (to ensure sub-
cooling).
• Do not manifold multiple refrigerant circuits into a
single condenser.
• If air-cooled condenser is located below chiller, refer to
condenser manufacturer’s performance data for avail-
able liquid lift.
• Refer to condenser installation instructions for location
guidelines.
Carrier recommends that a field-supplied pressure relief de-
vice be installed in each discharge line of 30MPA units. Most
local codes require the discharge line relief valve to be vented
directly to the outdoors. The vent
must not
be smaller than the
discharge line relief valve outlet.
EVACUATION AND DEHYDRATION — Because the
30MP systems use polyolester oil which can absorb moisture,
it is important to minimize the amount of time that the system
interior is exposed to the atmosphere. Minimizing the exposure
time of the oil to the atmosphere will minimize the amount of
moisture that needs to be removed during evacuation.
Once all of the piping connections are complete, leak test
the unit and then pull a deep dehydration vacuum. Connect the
vacuum pump to the charging valve in the suction line and to
the liquid line service valve. For best results, it is recommended
that a vacuum of at least 500 microns (0.5 mm Hg) be used.
Afterwards, to ensure that no moisture is present in the sys-
tem, perform a standing vacuum-rise test. With the unit in deep
vacuum (500 microns or less), isolate the vacuum pump from
the system. Observe the rate-of-rise of the vacuum in the sys-
tem. If the vacuum rises by more than 50 microns in a 30-min-
ute time period, continue the dehydration process. Maintain a
vacuum on the system until the standing vacuum requirement
is met. This will ensure a dry system.
By following these evacuation and dehydration procedures,
the amount of moisture present in the system will be
minimized.
30MPW CONDENSER DESCRIPTION — All 30MPW
units use a brazed-plate heat-exchanger-type condenser. These
heat exchangers are made of embossed plates of acid-resistant
stainless steel. Every other plate is reversed so that the ridges
of the herringbone pattern intersect one another on adjacent
plates, forming a lattice of contact points. These plates are
vacuum-brazed together to form a compact and pressure-
resistant heat exchanger.
After brazing, the impressions in the plates form 2 separate
systems of channels where the refrigerant and water flows are
counterflow. The number of plates varies depending on unit
tonnage. The condensers provide approximately 10º to 12º F
(6º to 8º C) liquid subcooling at the standard Air Conditioning,
Heating and Refrigeration Institute (AHRI) rating condition.
30MPW CONDENSER — When facing the unit control box,
the condenser is the uninsulated heat exchanger located on the
left-hand side. The water connections are on the right-hand
side of the heat exchanger with the LIQUID-IN connection at
the bottom, and the LIQUID-OUT connection at the top.
A strainer with a minimum of 40 mesh
must
be installed
within 10 ft (3 m) of the condenser water inlet to prevent debris
from clogging or damaging the heat exchanger. The strainer is
required for operation and is available as an accessory.
To install the victaulic coupling (see Fig. 11):
1. Use victaulic couplings designed for use on IPS dimen-
sioned materials. For example, Style 75, Style 77, Quick
Vic Style 107, or Style 177.
2. Lubricate the gasket lips and stretch the gasket over the
end of the heat exchanger coupling. Avoid twisting the
gasket when installing.
3. Bring the pipe and heat exchanger coupling ends together
into alignment. Slide the gasket so that it is centered over
the ends. Apply a light film of lubricant to the gasket, or
to the outside diameter of the pipe. Avoid twisting the
gasket during installation.
4. Install the inside coupling half over the gasket and then
install the outer half. Connect with nuts and bolts. Tighten
the nuts equally on both sides. Ensure there is no gap be-
tween the two halves of the coupling.
5. Alternately tighten the nuts with a wrench to draw the
coupling halves together uniformly. The joint is now
complete.
PIPE DIAMETER
(in.)
POUNDS PER 10 LINEAR FEET
(kg per 3m)
1
/
2
0.6 (0.27)
5
/
8
1.0 (0.45)
7
/
8
2.0 (0.91)
30MPA
UNIT
TOTAL LINEAR LENGTH OF
INTERCONNECTING PIPE
ft (m)
MINIMUM
TONNAGE WITH
DOUBLE RISER
0 - 200
(0 - 61.0)
Riser A
D (in.)
Riser B
D (in.)
015
7
/
8
1
1
/
8
1.
8
6
020
7
/
8
1
1
/
8
1.
8
6
030
7
/
8
1
1
/
8
1.
8
6
040
7
/
8
1
3
/
8
1.
8
6
045
7
/
8
1
3
/
8
1.
8
6
Fig. 10 — Double Discharge Riser
Construction Detail
a30-1245
TO
CONDENSER
B
RED.
TEE
90 DEGREE
STR ELLS
FROM
CHILLER
45 DEGREE
STR ELLS
A
LEGEND
RED. TEE
—
Reducing Tee
STR ELLS —
Street El
b
ows
a30-1979ef
