Danfoss PHT Serie Instrucciones página 2

Fig. 1 PHT 85
Fig. 3
I
PHTF R 12
PHTX R 22
PHTY R 502
PHTN R 134a
ENGLISH
Pilot-controlled, thermostatic
expansion valve
Technical data
Max. test pressure = 28 bar (P
Max. bulb temperature = 100°C
Fitting
PHT is designed for fitting in the liquid line
immediately before the evaporator, with flow in
the direction of the arrow. The valve must be
fitted horizontal with the pilot unit upwards (see
fig. 2). The pilot line is connected to the discharge
side of the valve immediately after the valve. If
required, a solenoid valve, EVR 3, can be inserted
in the pilot line. The external pressure equalising
line is connected to the suction line after the bulb.
The valve cannot operate unless pressure
equalising is connected.
The bulb is fixed in position with the bulb clip, its
best position being on the side of a horizontal
suction line.
The bulb can be placed warmer or colder than
the capillary tube or the valve (see fig. 3).
Fig. 4
Nr./No./n° »Y« ±0,2 mm
068B2089
068B2089
068B2089
068B2089
The bulb must not be fitted in or after liquid
pockets, pipe joints or iron and metal parts, nor in
places where it can be exposed to false
temperature effects.
Adjustment and service
Factory setting = 4°C superheat at 0°C bulb
) = 400 psig temperature. From this setting the superheat can
e
be decreased or increased dependent on the
application requirement. Anti-clockwise rotation
of the regulating spindle in the pilot valve
decreases superheat, clockwise rotation
increases it. One turn ~ 0.5°C.
The factory setting can be checked by measuring
the "Y" dimension of the pilot assembly. See fig.
4 and table I. Table I gives the code No. and "Y"
dimension for the pilot nozzle assembly (16).
Before the pilot valve is reassembled, after
checking the "Y" dimension the superheat
adjustment spindle must be pressed out and
retained by inserting the jaws of the spanner
supplied under the nut on the spindle (see fig. 5).
If a change of valve capacity is required the main
nozzle assembly (21) must be replaced (see
Spare Parts catalogue). Main nozzle assemblies
supplied separately are accompanied by three
band labels marked with refrigerant and rated
capacity.
Fig. 2
27
27
27
26
347
Fig. 5
After replacement of the main nozzle assembly
the old band label must be replaced by the one
marked with the refrigerant relevant to the
application.
Valve open override can be obtained by replacing
the base plug with a manual operating spindle,
code No. 026H0222.
Spare parts
See Spare Parts catalogue.