HVAC Procedure and Performance Guide

TASK: Install thermostatic expansion valve

Training for this procedure can be found in these courses:

                         131 – Oil Heat l  and  161 – Boilers l


Expansion valve must be located and installed according to manufacturer’s specifications and job specifications. Valve must be specified size and capacity for system. It must meter refrigerant to meet evaporator requirements and provide desired refrigerant superheat.  Valve connections must not leak.  Applicable safety procedures must be followed.


  1. Review manufacturer’s specifications and job specifications.
  2. Collect tools, equipment and materials.
  3. Put on safety and protective equipment and apparel.
  4. Determine type of connection and correct location for expansion valve.
  5. Verify that expansion valve is correct size, type and capacity for application and refrigerant used.
  6. Prepare tubing to install expansion valve and equalizer connection.
  7. Position valve according to manufacturer’s specifications.

a. Disassemble valve if required.

b. Connect valve in line. (Note:  Use heat-trap paste, wet cloths, etc., to protect valve body from excess heat during soldering).

c. Install equalizer line.

d. Reassemble valve if required.

e. Position and clamp thermostatic bulb at location specified by valve manufacturer. (Note:  Bulb capillary line must be routed and secured to avoid damage and vibration).

8. Remove safety and protective equipment and apparel.

9. Gather tools, equipment and leftover materials, and leave work site clean.

10.Test for leaks when refrigerant circuit has been completed; make required repairs.