4
CAUTION
APPLYING TOO MUCH HEAT TO ANY TUBE CAN MELT THE TUBE.
TORCH HEAT REQUIRED TO BRAZE TUBES OF VARIOUS SIZES
MUST BE PROPORTIONAL TO THE SIZE OF THE TUBE. SERVICE
PERSONNNEL MUST USE THE APPROPRIATE HEAT LEVEL FOR
THE SIZE OF THE TUBE BEING BRAZED.
9.4 Tubing Connections for TXV Version
TXV models come with factory installed adjustable TXV
with the bulb permanently located on the suction tube.
1. Remove coil access panel and rubber grommets.
2. Remove access valve fitting cap and depress the valve
stem in access fitting to release pressure. No pressure
indicates possible leak.
3. Reinstall the the Coil Access Panel & rubber grommets.
4. Remove the spin closure on both the liquid and suction
tubes using a tubing cutter. DO NOT USE A CUTTING
METHOD THAT WOULD RESULT IN THE GENERA-
TION OF COPPER SHAVINGS OR COPPER DUST.
SUCTION
LINE SET
SUCTION
TUBE
RUBBER
GROMMET
Figure 5.1
TORQUE 180-240 IN-LBS
ENSURE THAT SEAL
WASHERS STAY
IN POSITION
CC
Figure 5.2
CAUTION
EXCESSIVE TORQUE CAN CAUSE TXV RETAINING RING TO
WEAKEN & CREATE LEAK AND WILL BECOME DIFFICULT TO
RE-INSTALL TXV. USE THE PROPER TORQUE (180-240 IN. LBS)
SETTINGS WHEN TIGHTENING THE TXV OR HAND TIGHTEN
PLUS 1/2 TURN.
LIQUID
LINE SET
LIQUID
LINE
RUBBER
GROMMET
Figure 5.3
5. Insert liquid line set into liquid tube expansion and slide
grommet about 18” away from braze joint.
6. Insert suction line set into suction tube expansion and
slide insulation and grommet about 18” away from braze
joint.
7. Braze suction and liquid line joints.
9.5 Thermal Expansion Valve System Adjustment
Run the system at Cooling for 10 minutes until refrigerant
pressures stabilize. Use the following guidelines and meth-
ods to check unit operation and ensure that the refrigerant
charge is within limits. Charge the unit on low stage.
Purge gauge lines. Connect service gauge manifold to base-
valve service ports.
Temporarily install a thermometer on the liquid line at the
liquid line service valve and 4-6” from the compressor on the
suction line. Ensure the thermometer makes adequate contact
and is insulated for best possible readings. Use liquid line
temperature to determine subcooling and vapor temperature
to determine superheat.
Check subcooling and superheat. Systems with TXV appli-
cation should have a subcooling of 7 to 9ºF and superheat
of 7 to 9 ºF.
a. If subcooling and superheat are low, adjust TXV to 7
to 9 ºF superheat, then check subcooling.
NOTE: To adjust superheat, turn the valve stem clock-
wise to increase and counter clockwise to decrease.
b. If subcooling is low and superheat is high, add charge
to raise subcooling to 7 to 9ºF then check superheat.
c. If subcooling and superheat are high, adjust TXV valve
to 7 to 9 ºF superheat, then check subcooling.
