A - Condenser Pressure Drop, 50BVC,J,Q Units

Table 5A — Condenser Pressure Drop

50BVC,J,Q Units

FLOW RATE	SIZE 020	SIZE 024	SIZE 028	SIZE 034
(gpm)		Pressure	Drop (ft wg)
35	9.1	—	—	—
40	11.2	6.0	—	—
45	13.5	7.5	—	—
50	15.9	9.1	9.1	—
55	18.4	10.9	10.9	—
60	21.1	12.8	12.8	10.8
65	23.9	14.8	14.9	12.7
70	27.4	17.0	17.2	14.7
75	—	19.3	19.6	16.9
80	—	21.7	22.2	19.2
85	—	—	24.9	21.7
90	—	—	27.8	24.3
95	—	—	30.8	27.1
100	—	—	34.0	30.0
105	—	—	—	33.1
110	—	—	—	36.3
115	—	—	—	39.7
120	—	—	—	43.2

LEGEND

GPM — Flow Rate

PD — Pressure Drop (ft wg)

Table 5B — Condenser Pressure Drop

50BVT,V,W Units

FLOW RATE	SIZE 034	SIZE 044	SIZE 054	SIZE 064
(gpm)		Pressure	Drop (ft wg)
60	8.7	—	—	—
70	11.9	—	—	—
80	15.5	6.3	—	—
90	19.6	8.0	—	—
100	24.2	9.9	6.0	—
110	29.3	12.0	7.3	—
120	34.9	14.3	8.7	8.7
130	—	16.7	10.2	10.2
140	—	19.4	11.8	11.8
150	—	22.3	13.6	13.6
160	—	25.3	15.5	15.5
170	—	—	17.4	17.4
180	—	—	19.6	19.6
190	—	—	21.8	21.8
200	—	—	24.2	24.2
210	—	—	—	26.6
220	—	—	—	29.2
230	—	—	—	31.9
240	—	—	—	34.8

LEGEND

GPM — Flow Rate

PD — Pressure Drop (ft wg)

Pressure and temperature ports are recommended in both the supply and return lines for system flow balancing. These openings should be 5 to 10 pipe diameters from the unit water connections. For thorough mixing and temperature stabiliza- tion, wells in the water piping should extend at least 1/2 pipe diameter into the pipe. Measuring the condenser waterside pressure drop and referring to Tables 5A and 5B can help to properly set the water flow rate.

Improper fluid flow due to valving, piping, or improper pump operation constitutes abuse that may result in voiding of unit warranty. The manufacturer will not be responsible for damages or failures resulting from improper piping design or piping material selection.

EVAPORATOR CONDENSATE DRAIN — The condensate drain connection is 11/4-in. FPT and is located on the same side of the unit as the condenser water connections. See dimension drawings (Fig. 2-14) for exact location.

Drain lines should be pitched away from the unit with a minimum slope of 1/8-in. per foot and conform to all local and national codes.

A trap must be installed in the condensate line to ensure free condensate flow (units are not internally trapped). A vertical air vent is sometimes required to avoid air pockets.

Install a condensate-trapping drain line at the units drain connection. See Fig. 20 for correct drain layout.

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1/2 P1

Fig. 20 — Condensate Drain Layout

When calculating trap depth, remember that it is not the total static pressure but the upstream or downstream static resistance that is trapped against. For instance, when calculat- ing the trap depth for a cooling coil condensate pan, trap against the coil pressure drop in that coil section and any other pressure drops upstream of it.

If calculating the trap depth for the cooling coil, use the total static pressure drop (coil plus any other components upstream of it) plus 1 in. (P1 = negative static pressure + 1 in.), as shown in Fig. 21.

Traps must store enough condensate to prevent losing the drain seal at start-up. The “Minimum 1/2 P1” dimension ensures that enough condensate is stored.

Drain pans should be cleaned periodically to avoid the build-up of dirt and bacterial growth.

HOT WATER HEATING COIL (Optional) — A factory-installed one or 2-row hot water heating coil is available as an option. The coil is supplied with hot water from a boiler through separate pip- ing from the condenser water loop. All controls for heating opera- tion are field-supplied.

Piping should be in accordance with accepted industry standards and all components rated for the system pressure expected. Pipe the coils so that they will drain, and provide a drain and vent.

Always connect the supply to the top of the coil, and the return to the bottom. Refer to Fig. 2-14 for hot water supply and return piping locations.

Water coils should not be subjected to entering air tempera- tures below 38 F to prevent coil freeze-up. If air temperatures across the coil are going to be below this value, use a glycol or brine solution. Use a solution with the lowest concentration that will match the coldest air expected. Excess concentrations will greatly reduce coil capacity.

The return air duct system should be carefully designed to get adequate mixing of the return air and outdoor air streams to prevent cold spots on the coil that could freeze.

A 2 or 3-way, field-supplied modulating control valve, or a simple 2-position on-off valve may be used to control water flow. Select the valve based on the control valve manufacturer's recommendations for size and temperature rating. Select the control valve CV based on pressure drop and flow rate through the coil. This information is available from the VPACBuilder software program or Tables 6A and 6B.