Installation Guide

Expansion Valve System

NOTE: Units matched with indoor coils equipped with non-

adjustable TXV should be charged by subcooling only.

1. Purge gauge lines. Connect service gauge manifold to

base-valve service ports. Run system at least 10 minutes

to allow pressure to stabilize.

2. 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 sub-cooling and va-

por temperature to determine superheat.

3. Check subcooling and superheat. Systems with TXV ap-

plication should have a subcooling of 7 to 9 ºF and super-

heat 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

clockwise to increase and counter clockwise to de-

crease.

b. If subcooling is low and superheat is high, add charge

to raise subcooling to 7 to 9 ºF then check super-

heat.

c. If subcooling and superheat are high, adjust TXV

valve to 7 to 9 ºF superheat, then check subcooling.

d. If subcooling is high and superheat is low, adjust

TXV valve to 7 to 9 ºF superheat and remove charge

to lower the subcooling to 7 to 9 ºF.

NOTE: Do NOT adjust the charge based on suction pres-

sure unless there is a gross undercharge.

4. Disconnect manifold set, installation is complete.

Subcooling Formula = Sat. Liquid Temp. - Liquid Line Temp.

NOTE: Check the Schrader ports for leaks and tighten valve

cores if necessary. Install caps finger-tight.