Operating instructions

38
9C. SHORT CYCLE
A. AIR DISTRIBUTION BOX INSTALLATIONS
Short cycle is caused by cold air being drawn back into the
intake side of the air conditioner before it is mixed with the
warmer room air. This may cause the evaporator coil to
freeze up, causing the cold control to open the circuit to the
compressor.
Two possible causes of this condition are the air box and
the discharge duct. If the air box is not sealed tightly
against the ceiling, it will allow cold air to cross over into the
return air portion of the air box. Also, if the discharge duct
is not installed properly, it can allow cold air to cross over
into the return portion of the air conditioner. Make sure you
have the correct discharge duct for the thickness of the
roof. Seal all problem areas as necessary. You may need
to use tape to seal the discharge duct. Also, make sure the
discharge louvers are not restricted.
B. DUCTED INSTALLATIONS
Short cycle could be caused by air being circulated directly
on the remote sensor. Make sure you do not have a
register too close to the remote sensor. Verify the duct
connection at the unit is not leaking into the return air. Seal
all problems areas.
10C. AIR FLOW OBSTRUCTION
The coils and filters must be kept clean. Obstructions
reduce the amount of air passing through the coils. Dirt
acts as an insulator reducing the heat transfer across the
fins. Turn the air conditioner circuit breaker to OFF. Brush
the fins with a soft bristle brush, and vacuum up the
residue. The filters should be cleaned in a soap solution
and rinsed in clean water. Air-dry the filters before reinstall-
ing; a wet filter can cause insufficient cooling or freeze-up.
VACUUM
HOSE
EVAPORATOR
COIL
EVAPORATOR
COVER
FIN COMB
AIR
FILTER
11C. AIR DISTRIBUTION SYSTEM
A. ROOFTOP UNITS
SIZING & DESIGN
The installer of this air conditioner system must design the air
distribution system for his particular application. Several re-
quirements for this system MUST be met for the air conditioner
to operate properly. These requirements are as follows:
Roof cavity thickness must be between 2.00" to 5.50" . This
distance is measured between roof and ceiling surface.
The total cross-sectional discharge area of outlet ducts from
the plenum area under the air conditioner must be as follows:
1. 579 & 600 Series 17.5 sq.in.
2. 591, 595 & 630 Series21.0 sq. in.
Duct Sizing Requirements as Follows:
MIN. MAX.
Duct Depth (591/595/630 Series) 1-1/2" 2-1/4"
(579/600 Series) 1-1/4" 2-1/4"
Duct Width 7.00" — —
Total Duct Length 12 ft. 36 ft.
Duct Length (short run) 1/3 Total Length
Register Requirements as Follows:
MIN. MAX.
Distance from Duct End 5" 8"
Distance from End of Elbow 15" — —
Distance between Registers 24" — —
Total Number Required/AC 4 8
Number required per Run/AC 2 — —
Free Area per Register 14 sq. in. — —
The duct material must meet or exceed any agency or RVIA
Standard that may be in existence at the time the RV is
produced.
IT IS THE RESPONSIBILITY OF THE INSTALLER OF
THIS SYSTEM TO ENSURE THE DUCTWORK WILL
NOT COLLAPSE OR BEN DURING OR AFTER THE
INSTALLATION.
All discharge air ducts must be properly insulated to prevent
condensation from forming on their surfaces or adjacent
surfaces during operation of the air conditioner or heat pump.
This insulation must be R-7 minimum.
Ducts and their joints must be sealed to prevent condensation
from forming on adjacent surfaces during operation of the air
conditioner.