FIG. 6 - RETURN AIR GRILLE ACCESSORY
(Vertical Arrangement Shown)
Form
Form
Form
The supply air plenum and the return air grille should be used in lieu of ductwork only when a free blow/free return application is practical.
REFRIGERANT MAINS
Many service problems can be avoided by taking adequate precautions to provide an internally clean and dry system and by using procedures and materials that conform with estab- lished standards.
Use hard drawn copper tubing where no appreciable amount of bending around pipes or other obstructions is necessary. Use long radius ells wherever possible with one exception - small radius ells for any traps in a vapor riser. If soft copper is used, care should be taken to avoid sharp bends which may cause a restriction.
Fiber glass insulation and a sealing material such as perma- gum should be packed around refrigerant lines where they penetrate a wall to reduce vibration and to retain some flexibil- ity.
Support all refrigerant lines at minimum intervals with suitable hangers, brackets or clamps.
Braze all copper to copper joints with
Never braze or solder the liquid and vapor lines together. The complete vapor line should be insulated with minimum 1/2" AR- MAFLEX or equivalent.
If it is desirable to tape or wire these lines together for support purposes, they must be completely insulated, one from the other.
Refer to the installation instruction (Form
INSTALLING REFRIGERANT MAINS
WARNING: Provisions for recovering refrigerant releases must be available during all phases of installation, leak testing and charging. Do NOT release refrig- erant into the atmosphere.
The units are evacuated and dehydrated at the factory and shipped with a holding charge of an inert gas such as Nitrogen or Helium. The vapor and liquid connections are sealed with copper discs.
If the unit has already lost its holding charge, it should be leak tested and the necessary repairs should be made. If the unit has maintained its holding charge, you can assume that it has no leaks and proceed with the installation.
The temperature required to make or break a brazed joint is sufficiently high to cause oxidation of the copper unless an inert atmosphere is provided.
Drill a small hole through the discs to prevent any internal pres- sure from blowing them off and to allow the flow of dry nitrogen through the connections when unbrazing the closures.
The liquid and vapor connections must be piped outside the unit. Refer to the unit drawing for the locations and the dimen- sions of these connections.
Before brazing the refrigerant lines to these connections, re- move the short panel from the unit frame and slide the grom- mets onto the refrigerant lines. After the brazed joints have cooled, slide the grommets back into place and secure the panel to the unit frame.
NOTE: These coils can only be piped from one side of the unit.
DRAIN CONNECTION
The drain line MUST be trapped because the coil is located on the negative side of the supply air blower, and it must be pro- tected from freezing temperatures.
FIG. 7 - RECOMMENDED DRAIN PIPING
6 | Unitary Products Group |
