Carrier 30RAP010-060 installation instructions a30-4871

UNITS WITH FACTORY-INSTALLED HYDRONIC PACKAGES — The 30RAP chillers with factory-installed hydronic packages are designed for use with closed systems, meaning that there is no more than one water-air interface in the water loop. Cooling tower loops, for example, have two water-air interfaces (sump and nozzles) and would thus be clas- sified as open, whereas a correctly designed chilled water loop with the only water-air interface being in the expansion tank is closed. Since closed and open water systems behave very dif- ferently, these instructions assume that the chilled water loop is closed. A system installed incorrectly such that air is not han- dled properly — pipe leaks, vent leaks, air in pipes, etc. — may behave as an open system and thus have unsatisfactory opera- tion. Pump seal wear can also cause leaks that cause poor sys- tem operation.

Proper closed system design and installation procedures should be followed closely. The system must be constructed with pressure tight components and thoroughly tested for installation leaks. Factory-supplied hydronic systems are avail- able with single or dual (for back-up) pumps.

Figure 11 shows a typical installation with components that might be installed with the hydronic package of the 30RAP unit. The factory-installed system includes all of the compo- nents within the dashed lines. Figure 12 illustrates a typical dual pump package for the 010-030 size models.

NOTE: For units with single pumps, it is recommended that isolation (shutoff) valves be placed exterior to the unit to allow removal and service of the entire pump assembly, if necessary. Units with dual pumps have pump isolation valves provided. Also, if the unit is isolated with valves, a properly sized pressure relief valve should be installed in

the piping between the unit and the valves, following all applicable state and local codes.

System Pressurization — A proper initial cold fill pressure must be established before the filling of the unit. The initial cold fill pressure is the pressure applied at the filling point to fill a system to its highest point, plus a minimum pressure at the top of the system (4 psi minimum) to operate air vents and pos- itively pressurize the system.

The compression tank (sometimes called expansion tank) is very important to system pressurization. The compression tank actually serves several purposes:

1.Provide net positive suction head required (NPSHR) for the pump to operate satisfactorily.

2.Set system pressure.

3.Accommodate expansion/contraction of water due to temperature changes.

4.Acts as a pressure reference for the pump.

The compression tank pressure must be set BEFORE the system is filled. The tanks are pre-charged at the factory to 40 psig (276 kPa). If the 30RAP unit with expansion tank is the high point in the system, tank pre-charge pressure of 40 psig (276 kPa) will be adequate. If the 30RAP unit with expansion tank is NOT at the high point in the system, then the minimum pre-charge pressure for the water system must be determined using Table 2 and the method below:

Tank Pressure = 4 + (height from tank to top of system in feet/“X”)

[27.6 + (height in m x 22.6/”X”)]

2

14

12 11

1

13

7

5 6

3

4

6

12 11 9 8

	10
				LEGEND
1	— Strainer/Blow-Down Valve	8	—	Flow Switch	---Factory Supplied
2	— Expansion Tank	9	—	Balance Valve/Drain Plug
3	— Pump	10	—	Pressure Relief
4	— Electric Heater	11	—	Isolation Valves
5	— Air Vent Connection Port	12	—	Flex Connections
6	— Pressure/Temperature Access Port	13	—	Pressure Reducing/Fill Valve	a30-4871
7	— Heat Exchanger	14	—	Air Separator and Vent

Fig. 11 — Typical Piping Diagram — 30RAP Units with Hydronic Package

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