Greenheck Fan 474118 installation manual Drain Trap, Coils, Installation of Water Coil Piping

1¼ inch minimum

TSP

H/2

TSP = Total Static Pressure H = TSP + 1¼ inch minimum

Drain Trap

Coils are provided with a stainless steel drain pan with 1 1/4-inch male NPT drain connection. A drain trap must be connected to the drain connection to allow excess water to flow out of the drain pan. More importantly though, due to the negative internal static pressure of the coil compartment, installing the drain trap prevents outdoor air from being pulled into the drain pan and consequently forcing water out of the pan and into the unit.

To ensure the drain trap works properly, the trap height must account for the difference in static pressure between ambient conditions outside the unit and the internal negative pressure of the coil compartment.

Refer to local codes to determine drainage requirements. If draining onto roof, place a drip pan below drain to protect roof. If draining onto roof is not acceptable, a drain line must be attached to the trap. The drain line must be pitched away from the unit at least 1/8-in. per foot. On longer runs, an air break should be used to ensure proper drainage. Local codes may require drainage into a waste water system.

Drainage problems not only occur from improper drain trap design, but also from lack of maintenance of the cooling coil compartment. Algae can form in the drain pan and trap

and cause reduced

water flow, which can result in backup into the system. Regular

maintenance will prevent this from

occurring. If the drains have a clean-

out opening, be sure to close the opening after cleaning.

NOTE

A conservative method of trap design is to add 1-1/4 inches minimum to total static pressure.

Coils

Installation of Water Coil Piping

Guidelines for the installation of the coil have been provided to ensure proper performance of the coils and their longevity. These are general guidelines that may have to be tailored to meet the specific requirements of any one job. As always, a qualified party or individual should perform the installation and maintenance of the coil. Protective equipment such as safety glasses, steel toe boots and gloves are recommended during the installation and maintenance of the coil.

All field piping must be self-supporting. System piping should be flexible enough to allow for the thermal expansion and contraction of the coil.

Water Coil Installation Recommendations

1.Piping should be in accordance with accepted industry standards. Always use a back up wrench on the coil connections when attaching the piping to the coil if pipe thread connections are utilized.

2.Connect the water supply to the bottom connection on the air leaving side and the water return to the top connection on the air entering side.

3.The air vent at the uppermost point should be temporarily opened during system start-up to release all of the air from the coil. To maintain heat transfer capacity, periodically vent any air in the coil.

4.Water coils are not normally recommended for use with entering air temperatures below 40°F. Glycol solutions or brines are the only freeze-safe media for operation of water coils for low entering air conditions.

5.Two position control valves, modulating valves, three way valves or a combination of these controls can accomplish control of water coils. Follow the recommendations of the control manufacturer regarding types, sizing and locations. Face and bypass dampers may also be used, but do not close off tightly. Air leakage in cooling applications has no appreciable affect. In heating applications, however, the air temperature may rise several degrees and should be considered in system design. Low leakage dampers may be required.

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