Proto-Aire EZ I/O Manual
P/N
3090249_E
12
REFRIGERATION PIPING
Important:
Since Hussmann has no direct control over the installation, providing
freeze-burst protection is the responsibility of the installing contractor.
Always use a pressure regulator with a nitrogen tank.
Do not exceed 2 psig and vent lines
when brazing. Do not exceed 350 psig for leak testing high side. Do not exceed 150 psig for leak
testing low side.
Always recapture test charge in approved recovery vessel for recycling.
Overview
This section details the major refrigeration components and their locations in each piping
system.
Refrigeration Line Piping
Use only clean, dehydrated, sealed refrigeration grade copper tubing. Use dry nitrogen in the
tubing during brazing to prevent the formation of copper oxide. All joints should be made with
silver alloy brazing material, and use 35% silver solder for dissimilar metals.
Liquid and suction lines must be free to expand and contract independently of each other.
Do not clamp or solder them together. Run supports must allow tubing to expand and contract
freely. Do not exceed 100 feet without a change of direction or an offset. Plan proper pitching,
expansion allowance, and P-traps at the base of all suction risers. Use long radius elbows to
reduce flow resistance and breakage. Avoid completely the use of 45° elbows. Install service
valves at several locations for ease of maintenance and reduction of service costs. These must be
UL approved for 450 psig minimum working pressure.
Return Gas Superheat
Return gas superheat should be 20 to 30 °F on all units.
Suction Line
1. Install a downward slope in direction of flow. A P-trap is required for all vertical risers.
2. Line may be reduced by one size after first third of case load and again after the second
third.
3. Suction returns from evaporators must enter at the top of the line.
4. A minimum pitch of 1/2” per 10 feet of horizontal run should be used.
5. To facilitate proper oil return from, a suction branch should enter the main suction
return on the top of the main suction return.
