Resideo (Honeywell) TMVX-00105 Thermostatic Expansion Valve – R134a/R401A/R12, External Equalizer, +15…−30 °C, Interchangeable Orifice

Resideo (Honeywell) TMVX-00105 is an externally equalized (external equalizer) thermostatic expansion valve body for R134a (and R401A, R12). Evaporating range +15 … −30 °C — the operating band of refrigerated display cases and cabinets, milk cooling tanks, water chillers and vehicle air conditioning. The orifice is changed as a cartridge: depending on the cartridge selected, the same body serves from 0.36 kW to 15.9 kW (R134a).

The Valve for Medium-Temperature Refrigeration: Display Cases, Cabinets, Milk Tanks, Chillers

R134a is the refrigerant of medium-temperature applications; the +15 °C upper limit of this valve covers high evaporating temperatures such as chillers and milk tanks, while the −30 °C lower limit covers non-freezer cold storage. The thermostatic charge also covers R12 and R401A: when converting (retrofitting) an old R12 system to R401A or R134a, the valve stays the same; only the orifice capacity is recalculated.

Why external equalization? If the evaporator has a liquid distributor, or the circuit is long and multi-pass, there is a pressure drop between inlet and outlet. Because an internally equalized valve sees only the inlet, it reads the superheat too high and underfeeds the evaporator. The 7/16" UNF equalizer line of the TMVX is connected to the evaporator outlet; the valve opens according to the actual suction pressure. Honeywell makes external equalization mandatory in systems with distributors. Thanks to the adsorption (combination) charge, the charge responds only to the sensing bulb even if the capillary tube and valve head warm up — it is stable in systems with hot gas defrost.

Technical Specifications (Official Honeywell Product Data EN0H-1900GE23)

• Model: Resideo (Honeywell) TMVX-00105 — valve body + sensing bulb clamp; orifice cartridge not included
• Type: thermostatic expansion valve, externally equalized, interchangeable orifice, no MOP
• Refrigerants: R134a · R401A · R12 (single thermostatic charge)
• Evaporating range: +15 … −30 °C
• Max. pressure: PS 34 bar(a) · test pressure PF 37.4 bar(a)
• Connections: inlet 5/8" UNF · outlet 3/4" UNF (flare nut / flare) · equalizer line 7/16" UNF
• Capillary tube: 1.5 m · sensing bulb Ø12 mm · max. bulb temperature 140 °C
• Static superheat setting: ≈3 K (adjusted with the spindle; 1 turn ≈ 0.55 bar)
• Material: brass body · stainless steel thermostatic head and diaphragm
• Weight: ≈0.36 kg — official dimensional drawing in the 2nd image

Orifice Cartridge Selection — R134a Capacities

The capacity is determined by the cartridge, not the body. Official table conditions: t0 = +4 °C, tc = +38 °C, 1 K subcooled liquid. As the evaporating temperature drops, the actual capacity decreases — if you are at the limit, choose the next larger cartridge.

• 🚨 A valve without an orifice does not pass refrigerant. Order the TMVD cartridge that matches your capacity together with the body; the cartridges are listed as separate products in our catalog.
• 🔧 Equalizer line: taken with 6 mm / 1/4" tube from the top of the suction line, after the sensing bulb; leave a loop (overbow) so that oil does not escape. A TMVX without a connected equalizer line will not work properly.
• 🔧 Sensing bulb: on the upper half of the horizontal suction pipe, before the liquid trap; do not crush it when tightening the clamp, and insulate it.
• 🔧 When tightening the flare nuts hold the body by its wrench flats; if a solder adapter is used, the body must not exceed 100 °C.
• Other members of the family: TMVX-00101 for R22/R407C, TMVX-00108 for R404A/R507A. Versions with MOP (pressure limiting) are also available — please specify if compressor start-up protection is required.