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Thermal Expansion Valves

Emerson Climate Technologies

Other TXV Considerations

Solenoid Liquid Stop Valves

The TXV is produced as a tight seating device. But

if the TXV is exposed to dirt, moisture, corrosion, and

erosion the TXV will not be able to positively shut off.

If the remote bulb is installed in a location where during

the “off’ cycle it is inuenced by a higher ambient tem-

perature than the evaporator, the valve will open and ad-

mit liquid to the evaporator. Installing a Solenoid Liquid

Stop Valve ahead of any TXV is highly recommended.

Filter driers for System Protection

To protect the precision working parts of control

valves from dirt and chips which can damage them and

make them inoperative, and to protect the entire system

from the damaging affects of moisture, sludge and ac-

ids, a lter drier should be installed on every system.

Pressure Switch Setting

On TXVs with M.O.P., a Pressure Switch must be set

to cut in at a pressure lower than M.O.P. rating of the

TXV.

Emerson TXVs

Emerson’s TXVs are designed for a wide range of air

conditioning, refrigeration, heat pump, and chiller ap-

plications. Emerson uses stainless steel power elements

that will not corrode.

Emerson’s integral TXV line includes valves for com-

mercial and refrigeration applications, and heat pump

and residential applications. The “Take-Apart Series”

TXVs are available for almost any type of application,

temperature range, or refrigerant. Emerson also offers a

complete line of specialty TXVs.

Factory Superheat Setting

Unless otherwise specied, all Emerson TXVs will

be preset at the factory at a bath temperature which is

pre- determined by the charge symbol or the MOP rat-

ing. The bath temperature at which the TXV superheat is

set is coded alphabetically in the superheat block on the

TXV nameplate, as shown in Fig. 15.

Fig. 15

For example, a TXV with “10A” stamped in the name-

plate superheat block is set for 10°F static superheat

with a 32°F bath. A TXV stamped “10C” is set for 10° of

static superheat with a 0°F bath.

When ordering a TXV for an exact replacement,

specify the code letter and the superheat setting de-

sired. When ordering for general stock, it is not neces-

sary to specify either the superheat or the code letter,

since the standard setting will cover most applications

and minor superheat adjustments may be made in the

eld.

Degrees of SH Per Turn

Valve “Total R-22 R-134a R-404A/507 R-410A

Family Turns” +20°F -20°F +20°F +20°F -20°F +40°F

A 8 3.0 5.0 4.5 2.0 4.0 2.0

C/NXT 12 – – – – – 4.0

HF 10 2.2 4.2 3.8 1.8 3.2 N/A

TF 10 3.0 5.0 4.5 2.0 4.0 2.0

TRAE 10 2.2 4.2 3.8 1.8 3.2 N/A

TCLE 32 0.8 1.5 1.0 0.5 1.0 N/A

TXV SUPERHEAT ADJUSTMENT

Turn adjustment clockwise to increase superheat, counter-

clockwise to decrease superheat. To return to approximate

original factory setting, turn adjustment stem counterclock-

wise until the spring is completely unloaded (reaches stop or

starts to “ratchet”). Then, turn it back in one half of the “Total

Turns” shown on the chart.

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