900589-UIM-A-1012
4Johnson Controls Unitary Products
CRITICAL COIL PROJECTION
The coil assembly must be located in the duct such that a minimum dis-
tance is maintained between the top of the coil and the top of the duct.
Refer to Table 4.
SECTION IV: DUCT CONNECTIONS
The vast majority of problems encountered with combination heating
and cooling systems can be linked to improperly designed or installed
duct systems. It is therefore highly important to the success of an instal-
lation that the duct system be properly designed and installed.
Use flexible duct collars to minimize the transmission of vibration/noise
into the conditioned space.
Where return air duct is short, or where sound may to be a problem,
sound absorbing glass fiber should be used inside the duct. Insulation
of duct work is a must where it runs through an unheated space during
the heating season or through an uncooled space during the cooling
season. The use of a vapor barrier is recommended to prevent absorp-
tion of moisture from the surrounding air into the insulation. The supply
air duct should be properly sized by use of a transition to match unit
opening. All ducts should be suspended using flexible hangers and
never fastened directly to the structure. Duct work should be fabricated
and installed in accordance with local and/or national codes. This
includes the standards of the National Fire Protection Association for
Installation of Air-Conditioning and Ventilating Systems, NFPA No. 90B.
SECTION V: CONDENSATE DRAIN
CONNECTIONS
All drain lines should be pitched away from unit drain pan and should be
no smaller than the coil drain connection.
Route the drain line so that it doesn’t interfere with accessibility to the
coil, furnace, air handling system or filter and will not be exposed to
freezing temperatures.
Instruct the owner that the evaporator coil drain pan should be
inspected and cleaned regularly to prevent odors and assure proper
drainage.
Coils should be installed level or pitched slightly toward the drain end.
Suggested pitch should not exceed 1/4-inch per foot of coil.
If the coil is provided with a secondary drain it should be piped to a loca-
tion that will give the occupant a visual warning that the primary drain is
clogged. If the secondary drain is not used it must be capped.
DO NOT use TeflonTM tape, “pipe dope”, or other sealants. The use of a
sealant may cause damage and premature failure of the drain pan.
SECTION VI: REFRIGERANT LINE
CONNECTION
Connect lines as follows:
1. Suction and liquid line connections are made outside the duct.
2. Wrap a water soaked rag around the coil connection tubes inside
the duct to avoid damaging the TXV bulb.
3. Purge refrigerant lines with dry nitrogen.
4. Braze the suction and liquid lines.
5. Attach the duct access panel to the duct.
Refer to Outdoor unit Installation Manual for evacuation, leak check and
charging instructions.
Lines should be sound isolated by using appropriate hangers or strap-
ping.
All evaporator coil connections are copper-to-copper and should be
brazed with a phosphorous-copper alloy material such as Silfos-5 or
equivalent. DO NOT use soft solder.
FIGURE 5: Upflow Coil Installation
TABLE 3:
Coil Projection Dimensions - UC Coils
COIL SIZE DIMENSION “C” INCH
UC18 3-1/2
UC24 4-1/2
UC30 4-1/2
UC36 5-1/2
UC48 6-1/2
UC60 9
Dimension “C” should be at least 2/3 of dimension “D”. See Figure 5.
Equipment should never be operated without filters.
FIELD
FABRICATED
COIL ACCESS
FIELD
FABRICATED
SUPPORT
BRACKETS (x2)
“C” (MIN.)
“D”
FIELD
FABRICATED
DUCTWORK
3” (MIN.)
UPFLOW
FURNACE
AIR
FLOW
Avoid Double Trapping.
Threaded drain connections should be hand tightened, plus no more
than 1 turn.
Coil is under inert gas pressure. Relieve pressure from coil by
depressing schrader core.
Dry nitrogen should always be supplied through the tubing while it is
being brazed, because the temperature required is high enough to
cause oxidation of the copper unless an inert atmosphere is provided.
The flow of dry nitrogen should continue until the joint has cooled.
Always use a pressure regulator and safety valve to insure that only
low pressure dry nitrogen is introduced into the tubing. Only a small
flow is necessary to displace air and prevent oxidation.
Route the refrigerant lines to the coil in a manner that will not
obstruct service access to the coil, air handling system, furnace flue
or filter.
