Expansion Valve T Series

The T series is a thermostatic expansion valve for small and medium refrigeration and air-conditioning circuits. It meters liquid refrigerant into the evaporator at the rate the load requires, holding a constant superheat at the evaporator outlet, and it does this without any electrical supply - the bulb clamped to the suction line provides the signal.

The model code carries two pieces of information that make selection straightforward. The first letter states the refrigerant: T for R22, N for R134a, S for R404A and R507, F for R12, Y for R502 and Z for R407C. The E prefix marks the externally equalised version, used where the evaporator has a distributor or a significant pressure drop. So TX2 and TEX2 are both R22 valves, the second with external equalisation, and the same pattern runs through all twelve models.

Capacity is set by the orifice, not by the body: the valve accepts interchangeable orifices from #X up to #6, covering 0.38 kW to 16.7 kW (0.11 to 4.9 RT). One body can therefore be re-orificed when a system is modified instead of being replaced. The capacity table is published for each refrigerant across the full evaporating range, and the orifice has to be chosen from that table at the design evaporating and condensing temperatures.

Connections are 3/8 inch inlet by 1/2 inch outlet with a 1.5 m capillary - the standard arrangement for small condensing units, display cases, water chillers and cold room evaporators. Static superheat is adjustable from the bottom of the valve with the cap removed.

Installation points: keep the bulb in intimate contact with a clean horizontal section of suction line and insulate it from ambient; mount the body upright; and on externally equalised versions take the equaliser from the suction line downstream of the bulb.