Emerson ALCO CONTROLS HP Serie Instrucciones De Utilizacion

Emerson Electric GmbH & Co
Heerstr.111 - D 71332 Waiblingen
Tel.: 07151 509-0 - Fax.: -200
General information and technical data:
HP Regulators are used to maintain adequate condensing
pressure during low ambient conditions. Thereby
maintaining liquid subcooling and sufficient pressure
drop through Thermo Expansion Valve.
• Max. Operating Pressure PS:
• Max. Test Pressure PT:
• Operating Temperature Range TS: –40°C to 150°C
• Max. Ambient Temperature:
• Max. Transport Temperature:
• Max. body temperature:
• Compatibility: CFC, HCFC, HFC, Mineral- and Ester
HP
Lubricants
!
Safety instructions:
• Read Operationg instructions thoroughly. Failure to comply can result in
device failure, system damage or personal injury.
• It is intended for use by persons having the appropriate knowledge and
skill. Before attempting to install the HP Regulator make sure pressure in
system is brought to and remains at atmospheric pressure.
• Do not release any refrigerant into the atmosphere.
• Do not use any other fluid media without prior approval of Alco Controls.
Use of fluid not listed could result in:
Change of Hazard Category of the product and consequently change of
conformity assessment requirement for product in accordance with
European Pressure Equipment Directive 97/23/EC.
• In a severely contaminated system, avoid breathing acid vapours and avoid
contact with skin from contaminated refrigerant / lubricants. Failure to do
so could result in skin injury.
• HP Regulators are not released for use with flammable refrigerants such as
hydrocarbon refrigerants and ammonia.
Mounting location:
• HP Regulators should be installed according to Fig. 1. For heat-reclaim purpose
and parallel piping see Fig. 2-6 and 7.
• Regulators may be mounted in horizontal or vertical lines Up-side down
position is not recommended and can cause mal-function (Fig. 9).
Installation of Regulator:
• Connect Tubing according to Fig. 1 (Port C, B, and R) .
• Before brazing clean tubing.
• Direct flame away from valve body (Fig. 8). During brazing process the cooling
of the regulator body is necessary to avoid any internal damage (i.e. wet cloths).
Do not exceed max. body temperature of 150°C.
• Use an in ert gas such as nitrogen to pass through the valve to prevent copper
oxide formation.
• The use of appropriate brazing material is required (soft solder is not allowed).
Never use oxygen or flammable gases.
• Internal parts must be protected from foreign material and moisture. ALCO
filter-drier use in liquid line and ALCO filter use in suction line is
recommended.
• A pressure drop through the condenser (between port B and C) of 1.4 bar and
more will lead to mal-function (hot gas is permanently feeded into the receiver
even at high ambient temperatures leading to high pressure alarm).
Troubleshooting
Complaint
1. Low Condensing Pressure
during operation
2. System runs high condensing pressure
or cycles on high pressure cut-out
Document Nr.: A6.5.059 -
ALCO CONTROLS
28 bar
31 bar
-40 to 50°C
-40 to 70°C
150°C
Valve unable to throttle Port C because:
Foreign material wedged between Port C seat and seat
disc
Power element lost charge
Insufficient wintertime system charge
Wrong charge pressure in valve for system refrigerant
Receiver exposed to low ambient acting as a condenser Insulate receiver
Hot gas bypass line restricted or shut-off
Compressor not pumping or restriction in liquid line, or
low side causing very low suction pressure
Condenser fan(s) not running or turning wrong
direction
Fan cycling
Pressure drop through condenser exceeds 1,4 bar
forcing port C partially open
Condenser undersized or air flow restricted or short
circuiting
B port wedged open due to foreign material between
seat and seat disc
B port seat damaged due to foreign material
Wrong charge pressure in valve for system refrigerant
Excess system charge or air in system
Replacement for x...
Operating Instructions
Head Pressure Control Valves, Series HP
Leakage test:
• After completion of installation, a pressure test must be carried out as follows:
- According to EN378 for systems which must comply with European pressure
equipment directive 97/23/EC
- To maximum working pressure of system for other applications.
Warning:
Failure to do so could result in loss of refrigerant and personal injury.
The pressure test must be conducted by skilled persons with due respect
regarding the danger related to pressure.
Application:
With this type of pressure control additional liquid receiver capacity is required.
WARNING: Do not use HP Regulators in systems without Receiver.
To prevent compressor damage due to liquid accumulation on the compressor
head, good piping practice suggests a trap in the discharge line and an inverted
trap at the condenser inlet
In general, head pressure control systems of this type are used on refrigeration
systems which are temperature operated. This means that the compressor is
started by a thermostat or the system operates on a pump down cycle where the
thermostat controls the liquid line solenoid valve and the compressor starts on a
rise in suction pressure with a low pressure switch.
On systems which are pressure operated, provision should be made to prevent
migration of the refrigerant to the cold condenser on the "off" cycle. If the system
does not operate on a pump down cycle, migration can take place through some
compressors, from the suction line to the condenser. The use of crankcase heaters
will prevent liquid from condensing in the crankcase but will not eliminate
migration to the cold condenser. If the system is properly charged, the filled
condenser will permit the excess to remain in the receiver.
Under certain conditions where the receiver is located in a warm ambient, a
check valve in the liquid drain line between the HP control and the receiver may
be required to prevent the liquid receiver pressure from equalizing to that of the
condenser during the "off" cycle, thus enabling the system to start on a pressure
switch. Some systems may require a time delay on the low pressure switch.
Condenser fans should not be cycled when using the HP control. The sudden
changes in high side pressure caused by fan cycling will result in erratic
thermostatic expansion valve performance and shortened head pressure control
life.
Service:
• Before any service shut down system and disconnect from power source.
• After reducing pressure to atmospheric the regulator may be replaced (cannot
be repaired). In case of mal-function the regulator can be set to summer
conditions by releasing the pressure in the dome of the regulator(cut off the cap.
Tube). In that case there is full flow from port C to port R.
WARNING: When cutting off the cap tube liquid refrigerant could blow out.
Code for min. Condensing Temperature (°C)
(HP are factory set. Readjustment is not possible.)
Code R134a
95 30
135 40
165 47
225
Possible Cause
R22 R407C R507 / R404A
25
30 25
43 35
Corrective Action
Artificially raise Condensing Pressure and tap valve
body to dislodge foreign material
Change valve.
Add refrigerant
Change valve
Clear obstruction or open valve
Change or repair compressor or clear obstruction or
other reason for low suction pressure
Replace or repair fan motor, belts, wiring or controls as
required
Run condenser fans continuously while system is
running
Re-pipe, re-circuit or change condenser as required to
reduce pressure drop
Increase size of condenser or remove air flow
restriction or short circuit as required
Artificially reduce condensing pressure and tap valve
body to dislodge foreign material
Change valve
Change valve
Purge refrigerant or non-condensables as required
Date: 28.04.2003 DWG Nr.: EA/PCN 861376
GB
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