Greenheck Fan 470658 MSX manual Installation of Direct Expansion DX Coil Piping optional

Installation of Direct Expansion (DX) Coil Piping (optional)

Important

Guidelines for the installation of direct expansion cooling coils have been provided to insure proper performance and longevity of the coils. 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 any coil. Protective equipment such as safety glasses, steel toe boots and gloves are recommended during the installation and maintenance of the coil.

Important

All field brazing and welding should be performed using high quality materials and an inert gas purge (such as nitrogen) to reduce oxidation of the internal surface of the coil.

Important

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

1.Locate the Distributor(s) by Removing the Distributor Access Panel

Distributor Access Panel

Thermal

(by others)

(by others)

Installation with Hot Gas Bypass

2. Verify Nozzle Placement

Note

If a hot gas bypass kit was provided by others, refer to the manufacturer’s instructions.

3. Install Suction Line

Install suction line(s) from the compressor to the suction connection(s) which are stubbed through the side of the cabinet.

4.Install the Liquid Line and Thermal Expansion Valve (TEV) (by others)

Liquid line openings vary by coil size and circuiting and are field supplied. Follow the TEV recommendations for installation to avoid damaging the valve. If the valve is externally equalized, use a tubing cutter to cut off the plugged end of the factory installed equalizer line. Use a de-burring tool to remove any loose metal from the equalizer line and attach it to the TEV. If the valve is internally equalized, the factory installed equalizer line can be left as is.

	Suction Header	Coil
Liquid Line	Distributor
	Equalizer Line
	Nozzle

Thermal

Expansion

Valve (by others)

Suction Line
Remote Sensing Bulb	Straps
	Suction Connection

General Installation

5.Mount the Remote Sensing Bulb (by others)

The expansion valve’s remote sensing bulb should be securely strapped to the horizontal run of the suction line at the 3 or 9 o’clock position and insulated.

6. Check Coil Piping for Leaks

Pressurize the coil to 100 psig with dry nitrogen or other suitable gas. The coil should be left pressurized for a minimum of 10 minutes. If the coil holds the pressure, the hook-up can be considered leak free.

If the pressure drops by 5 psig or less, re-pressurize the coil and wait another 10 minutes. If the pressure drops again, there is likely one or more small leaks which should be located and repaired. Pressure losses greater than 5 psig indicate a large leak that should be isolated and repaired.

Inspect the refrigerant distributor and verify that the nozzle is in place. The nozzle is generally held in place by a retaining ring or is an integral part of the distributor itself.

Retainer	Nozzle Distributor
Ring

Nozzle Placement

7. Evacuate and Charge the Coil

Use a vacuum pump to evacuate the coil and any interconnecting piping that has been open to the atmosphere. Measure the vacuum in the piping using a micron gauge located as far from the pump as possible. Evacuate the coil to 500 microns or less, and then close the valve between the pump and the system. If the vacuum holds to 500 microns or less

® Model MSX Make-Up Air 13