Zanotti un0 080 - 3.5 Orifice and Expansion Valve

57
3.5 Orifice and Expansion
Valve
Cooling Circuit
(f) Connect refrigeration man- ifold
to LP low pressure and HPL liquid
hight pressure service p
orts.
(g) Vacuum contaminated part of
cooli
ng circuit only.
(h) Reopen unit valves.
3.5 Orifice and Expansion Valve
The
rmostatic expansion valve regulate the injection of refrigerant liquid into evaporators. It controls refrigerant flow by
superheat.
Required Parts
-
Expansion Valve
- Gaskets
- Tube Ins
u
lation
- Plastic Fastener
In
dividual Protection Devices
Goggles, Gloves
Expansion Valve Regulation
(a) Connect a low pressure gauge to
EVP evapor
ator or
to LP low
pressu
re service port.
(b) Set-up required set-
point temperat
ure on cab
command.
(c) Turn-on unit and pull-down cold-
room.
(d) Reached or close to required
temperature measure pressure.
(e) Check evaporator tempera- ture
close to sensing bulb.
(f) Calculate overheating
T
evp
Overheating
0
o
C (32
o
F
) 8
K
(14
o
F )
−
20
o
C (
−
4
o
F
) 4
K
(7
o
F )