Unicla 90 Series Assembly instructions

Compressor Fitting
Guidelines for
New Applications
®

Copyright ©2007
All rights reserved
No part of this document shall be reproduced in whole or in part without the permission of Unicla
International Ltd. This includes reproduction or copies in any form or by any means including
photocopying, printing or electronic media.
IMPORTANT DISCLAIMER
This is a guideline document containing professional information using representative graphs,
charts and tables. Manufacturers’ specications must be consulted for specic guidelines and
performance data. Unicla published data, specic to all models, is available in promotional literature
and from Unicla International Ltd on request or through your Unicla supplier.
Unicla International Ltd expressly disclaims all and any liability and responsibility to any person or
business as a result of any actions taken on the basis of information in this publication.
®

Compressor tting guidelines
for new applications
Table of contents
1 Compressor tting information ……………………………………………………… 2
2 System cleanliness …………………………………………………………………… 2
3 Mounting…………………………………………………………………………………3
4 Belt alignment and tension…………………………………………………………… 3
5 Compressor speed …………………………………………………………………… 4
6 Oil selection ………………………………………………………………………… 4, 5
7 Compressor selection ………………………………………………………………… 6
8 Hose and pipe selection ……………………………………………………………… 6
9 Recommended suction line pipe size …………………………………………… 7, 8
10 System validation ………………………………………………………………… 9, 10
11 Other features & performance information……………………………………… 11
Note: This booklet is designed to assist the installing technician to ensure Unicla
guidelines and procedures have been followed during the installation and initial
commissioning of Unicla compressors.
Please read carefully and if further information is required please visit: www.unicla.hk
or contact the nearest Unicla dealer.
1.

1. Compressor Fitting Information
This information will assist technical personnel to ensure correct tting procedures are adopted
to maximise the life of the compressor and associated components.
All Unicla compressors are manufactured to exacting standards using quality materials and
rigorous test programs to ensure reliability and durability are optimised.
It is important to recognise poor tting or servicing procedures as well as any mismatch of
compressors to systems as these factors can seriously jeopardise reliability and performance
and result in premature compressor failure or unacceptable performance losses.
The following guidelines must be strictly adhered to. The Unicla warranty against faulty
product (materials and workmanship) is subject to system compatibility and refrigerant and
lubricant compatibility.
a) Removing transit gas
Before mounting and when handling a new Unicla UWX compressor
for the rst time, remove the dust cap from the discharge service
valve and gently release the N2 gas as follows.
Take care to not let oil escape.
b) Initial lubrication
Rotate the compressor armature manually for 4-5 revolutions to
ensure proper lubrication to the working assembly components.
This will avoid damage during initial start up.
c) Service manual
If any disassembly of compressor components is required, the specic Unicla compressor
service manual must be consulted and the relative procedures strictly adhered to. UWX series
compressors require tting of the discharge line hose manifold to the appropriate left or right
hand side of the compressor. A separate installation instruction booklet is attached to the
compressor for this.
2. System Cleanliness
a) Contamination
The system must be free of both solid particle and chemical contamination before compressor
tting. Solid particle contamination will cause direct compressor damage and starvation due
to blocked system lters and screens (see section 10). Chemical contamination can reduce
solubility/miscibility of refrigerants and oils, reduce oil viscosity, and cause acid etching and
sludge formation.
b) Flushing
Contaminated systems must be ushed before tting the new compressor. Individual
component ushing is strongly recommended in systems where solid particle contamination
has occurred during the system assembly process. The compressor, TX valve, pressure control
valves, receiver driers/accumulators and muers/pulsation dampers - must not be ushed.
2.

a) Mounting points
All compressors should be mounted rmly and securely to the engine bracket using
manufacturers’standard specications. The following chart outlines the minimum mounting
point utilisation for each Unicla model.
b) Mounting angle
The mounting angle
for each model must
be as follows:
c) Lug type mounting
When mounting Unicla UP series compressors (lug mount type)
there must be no gap between the bracket and the lug. This will
ensure additional stress is not placed on the compressor and noise
transmission is kept to a minimum. Universal sliding bushes or shims,
or Unicla shim kit part no 2900-000010 must be used as follows:
4. Belt alignment and tension
a) Alignment
The compressor clutch pulley must be in perfect alignment
with the drive pulley on the engine and any auxiliary idler or
adjusting system. Unacceptable alignment is shown in the
following diagram
b) Tension
Belt tension adjustment should be made so the belt is taut, but not to excess to cause excessive
bearing loads. Due to the pulsating load created by compressors, the belt tension must be
greater than for a normal steady load. The tension must be within the manufacturers’ guidelines
for the specic belt used to drive the compressor, or in the absence of this information, Unicla
recommends belt deection of 10 - 20 mm /meter after tensioning, or 50kg of tension for most
applications. This tension must be checked again and tighten back to specication after 36-48
hours of initial operation.
3. Mounting
3.
Compressor type Mounting description Minimum mounting requirement
UC Alternator or swing type Three lugs
UP Lug type Four lugs
UX Direct or bolt through type Four points
UWX Multiple direct mounting Six points

4.
5. Compressor speed
a) Speed limit
When tting any compressor from the Unicla range, ensure that the compressor speed does
not exceed the specied limit. This includes both continuous speed and momentary speed.
Crank to compressor drive ratios are recommended to not exceed 1.2:1 to ensure maximisation
of compressor clutch and pulley durability. In low speed governed applications the gearing
ratio may exceed 1.2:1 to provide maximum performance providing the rated compressor
speed is not exceeded. The following chart gives the Unicla speed recommendation for each
model.
b) Pulley ratios
If excessive pulley ratio is
unavoidable, then consideration
should be given to tment of a
cut – o sensor for over speed.
c) Compressor rotation
The direction of rotation of the compressor must match the application in which it is being
placed. Unicla compressors are designed to operate in both clockwise and counterclockwise
directions. However, the clutch design varies depending on direction of rotation.
Later generation rubber clutches are designed to operate in both directions, making the
compressor and clutch assembly multi directional.
Failure to match the clutch with its direction of rotation may result in premature clutch
failure, especially in applications of high torque engagement spike (high head pressure)
and/or constant high speed cycling.
6. Oil selection
a) Recommended oil
Each Unicla compressor is tted with specic oil. The following chart outlines the
recommended selection of oil and refrigerant to common applications, however each
compressor is labelled separately with the refrigerant and oil type to be used.
Only this recommended refrigerant and oil should be used. Failure to comply with this
may result in dramatically reduced oil circulation rates with subsequent starvation of the
compressor. Warranty is void if non-approved oils and refrigerants are used.
Compressor
series
Ideal operation
speed rpm
Maximum
continuous rpm
Maximum
momentary rpm
90 1800-2400 3000 4500
120/150/170 1800-2400 3000 6000
200/330 1500/2500 3000 4500
440/550 1200/2500 3000 4500

b) Oil quantity
The correct amount of oil must be maintained in the compressor and system. Long hose runs
and dual evaporator systems must have additional oil added to the system.
Severe oil starvation problems may result from insucient system oil being allowed.
To determine oil quantity required Unicla recommends a calculation as a percentage of
refrigerant charge as follows:
- 20 % for Unicla A group compressors (90,120,150,170 series) in standard applications
- 30 % for Unicla B group compressors (200,330,440,550 series) in applications where suction and
discharge lines exceed 6m in length
Example: Calculate oil charge as 20% of refrigerant charge, 3 kg charge = 3000 g x 20%
= 600 ml (cc) of oil. If tting a UP200 compressor, then deduct the compressor
initial oil charge to determine amount of oil to be added.
Therefore 600 – 180 = 420cc oil to be added to system.
c) Matching oil
The oil added to the system must be identical to the native oil already installed to the specic
Unicla compressor as identied on the compressor label.
d) Oil separators
Oil separators are strongly recommended in multiple evaporator systems due to oil circulation
rate reduction and in systems where it is deemed the suction may go below zero, such as in
high speed operation or as per the system applications mentioned in the chart above.
5.
Compressor
Model
Refrigerant Oil
type
Viscosity
@40˚C
Viscosity
@100˚C
Application Low side
saturation
Oil
separator
UC R134a
Unicla Unidap 7 48.01 10.51 Airconditioning ≥0˚C Optional
UP & UX R134a Unicla Unidap 7 48.01 10.51 Airconditioning ≥0˚C Optional
UP & UX R134a Emkarate RL68H 65.5 9.3 Airconditioning ≥0˚C Optional
UP & UX R134a Emkarate RL68H 65.5 9.3 Airconditioning ≥-10˚C Required
UP & UX R404a Emkarate RL32H 32.5 5.8 Refrigeration ≥-15˚C Required
UPF R404a Emkarate RL32H 32.5 5.8 Refrigeration ≥-35˚C Required
UPF R404a Emkarate RL32H 32.5 5.8 Refrigeration ≥-15˚C Required
UWX R134a Unicla Unidap 7 48.01 10.51 Airconditioning ≥0˚C Optional
UWX R134a Emkarate RL68H 65.5 9.3 Airconditioning ≥0˚C Optional

7. Compressor selection
a) Selection criteria
When selecting compressors, or upgrading systems to larger capacity or to dual evaporators, the
compressor sizing (capacity) must match the system.
Compressor selection must be done using the following basic guidelines:
•What is the operational speed of the compressor?
This varies dramatically in highway to city cycle.
•What is the total net refrigerating capacity of the system? Evaporator rating.
•What refrigerant is being used in the system?
Taking into consideration these three factors and if the evaporator capacity is adequate for the
application, the correct compressor can be selected.
Note: Graphs will often incorporate three plots onto one grid – power
consumption, refrigerating capacity, and coecient of performance. Coecient
of performance relates to input (power consumption) versus output (refrigerating
capacity). If interpreting single plot graphs, ensure you have selected the
Refrigerating Capacity Graph. A complete range of graphs for each model is
available from Unicla upon request.
For single evaporator applications the compressor must cater for the net refrigerating capacity of
the evaporator at nominated operating speeds.
For dual evaporator units the compressor must cater for the net refrigerating capacity of all
evaporators.
8. Hose and pipe selection
a) Suction Line
Correct sizing of the suction line is critical to ensure adequate ow of refrigerant is maintained.
Too often the nominated capacity of the evaporator and the compressor are ideally matched, only
to be compromised by undersized piping in the suction line.
The following tables outline the required pipe or hose sizes for each Unicla compressor model
under common speed and capacity ratings.
The suction lines are sized to have pressure drop from friction no greater than the equivalent of
approximately 1 K change in saturation temperature. Selections are base on R134a saturation
temperature of 08C (Referenced from ASHRAE Hand Book, Refrigeration Volume, 2006 Edition.)
6.

9. Recommended suction line pipe size
The following charts give the suction pipe size recommendations for Unicla compressors.
7.
RPM Rated
(kW)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
1000 3 0.37 3.8 16
(5/8)
0.74 7.6 16
(5/8)
0.45 4.7 19
(3/4)
0.55 5.6 19
(3/4)
0.82 8.4 19
(3/4)
1500 4.9 0.74 7.5 16
(5/8)
0.54 5.6 19
(3/4)
0.91 9.3 19
(3/4)
1.09 11.2 19
(3/4)
0.76 7.8 22
(7/8)
2000 6.5 0.44 4.5 19
(3/4)
0.88 9 19
(3/4)
0.68 7 22
(7/8)
0.82 8.4 22
(7/8)
0.32 3.3 28
(1,1/8)
2500 7.9 0.58 5.9 19
(3/4)
0.53 5.5 22
(7/8)
0.89 9.2 22
(7/8)
1.08 11 22
(7/8)
0.42 4.3 28
(1,1/8)
3000 8.8 0.71 7.2 19
(3/4)
0.65 6.7 22
(7/8)
1.1 11.2 22
(7/8)
0.34 3.5 28
(1,1/8)
0.51 5.3 28
(1,1/8)
3 m Pipe Length 6 m Pipe Length 10 m Pipe Length 12 m Pipe Length
18 m Pipe Length
RPM Rated
(kW)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
1000 2.4 0.95 9.7 12
(1/2)
0.58 6 16
(5/8)
0.98 10 16
(5/8)
0.43 4.5 19
(3/4)
0.65 6.7 19
(3/4)
1500 3.6 0.59 6 16
(5/8)
0.43 4.5 19
(3/4)
0.72 7.4 19
(3/4)
0.87 8.9 19
(3/4)
0.61 6.2 22
(7/8)
2000 4.9 0.95 9.7 16
(5/8)
0.70 7.2 19
(3/4)
0.54 5.6 22
(7/8)
0.65 6.7 22
(7/8)
0.98 10 22
(7/8)
2500 6 0.45 4.6 19
(3/4)
0.91 9.3 19
(3/4)
0.7 7.2 22
(7/8)
0.84 8.6 22
(7/8)
0.33 3.5 28
(1,1/8)
3000 7.2 0.56 5.8 19
(3/4)
0.52 5.3 22
(7/8)
0.87 8.9 22
(7/8)
1.05 10.7 22
(7/8)
0.41 4.2 28
(1,1/8)
18 m Pipe Length
RPM Rated
(kW)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
1000 3.5 0.49 5.1 16
(5/8)
0.99 10.2 16
(5/8)
0.61 6.3 19
(3/4)
0.74 7.5 19
(3/4)
1.1 11.3 19
(3/4)
1500 5.8 1.01 10.3 16
(5/8)
0.74 7.6 19
(3/4)
0.57 5.9 22
(7/8)
0.69 7.1 22
(7/8)
1.04 10.6 22
(7/8)
2000 7.8 0.59 6 19
(3/4)
0.55 5.6 22
(7/8)
0.91 9.3 22
(7/8)
1.1 11.2 22
(7/8)
0.43 4.4 28
(1,1/8)
2500 9.3 0.78 8 19
(3/4)
0.72 7.4 22
(7/8)
0.31 3.2 28
(1,1/8)
0.38 3.9 28
(1,1/8)
0.57 5.8 28
(1,1/8)
3000 10.5 0.96 9.8 19
(3/4)
0.89 9.1 22
(7/8)
0.38 4 28
(1,1/8)
0.46 4.8 28
(1,1/8)
0.7 7.1 28
(1,1/8)
3 m Pipe Length 6 m Pipe Length 10 m Pipe Length 12 m Pipe Length
18 m Pipe Length
Unicla 150 Series Compressors
Unicla 170 Series Compressors
Unicla 200 Series Compressors
3 m Pipe Length 6 m Pipe Length 10 m Pipe Length 12 m Pipe Length

8.
RPM Rated
(kW)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
1000 9.9 0.79 8.1 19
(3/4)
0.73 7.5 22
(7/8)
0.32 3.3 28
(1,1/8)
0.55 4 28
(1,1/8)
0.58 5.9 28
(1,1/8)
1500 15.4 0.74 7.5 22
(7/8)
0.38 3.9 28
(1,1/8)
0.64 6.6 28
(1,1/8)
1.09 7.9 28
(1,1/8)
0.4 4.1 35
(1,3/8)
2000 20.1 0.31 3.2 28
(1,1/8)
0.62 6.4 28
(1,1/8)
1.04 10.6 28
(1,1/8)
0.82 4.4 35
(1,3/8)
0.65 6.7 35
(1,3/8)
2500 24.1 0.43 4.4 28
(1,1/8)
0.87 8.9 28
(1,1/8)
0.5 5.2 35
(1,3/8)
1.08 6.2 35
(1,3/8)
0.91 9.3 35
(1,3/8)
3 m Pipe Length 6 m Pipe Length 10 m Pipe Length 12 m Pipe Length
18 m Pipe Length
RPM Rated
(kW)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
1000 12.1 0.55 5.7 22
(7/8)
0.29 3 28
(1,1/8)
0.48 5 28
(1,1/8)
0.58 6 28
(1,1/8)
0.87 8.9 28
(1,1/8)
1500 18 0.29 3 28
(1,1/8)
0.58 6 28
(1,1/8)
0.98 10 28
(1,1/8)
0.41 4.2 35
(1,3/8)
0.61 6.3 35
(1,3/8)
2000 23 0.47 4.8 28
(1,1/8)
0.94 9.6 28
(1,1/8)
0.54 5.6 35
(1,3/8)
6.7 6.7 35
(1,3/8)
0.99 10.1 35
(1,3/8)
2500 26.7 0.64 6.5 28
(1,1/8)
0.44 4.5 35
(1,3/8)
0.74 7.6 35
(1,3/8)
0.89 9.1 35
(1,3/8)
0.56 5.7 41
(1,5/8)
3 m Pipe Length 6 m Pipe Length 10 m Pipe Length 12 m Pipe Length
18 m Pipe Length
Unicla 330 Series Compressors
Unicla 440 Series Compressors
Unicla 550 Series Compressors
9. Recommended suction line pipe size
... continued
b) Discharge line
Discharge line pipe or hose sizes should be calculated in consideration of the nominated suction
line sizes. In most applications this is set at one size under the suction line size.
Reference tables showing this are available from Unicla upon request.
RPM Rated
(kW)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
Temp
Diff
(K)
Press
Diff
(kpa)
Pipe
Size
mm
(inch)
1000 6.25 0.46 7.7 19
(3/4)
0.92 9.4 19
(3/4)
0.71 7.3 22
(7/8)
0.86 8.8 22
(7/8)
0.34 3.5 28
(1,1/8)
1500 9.25 0.94 9.6 19
(3/4)
0.87 8.9 22
(7/8)
0.38 3.9 28
(1,1/8)
0.45 4.6 28
(1,1/8)
0.68 7 28
(1,1/8)
2000 11.2 0.70 7.1 22
(7/8)
0.36 3.7 28
(1,1/8)
0.6 6.2 28
(1,1/8)
0.73 7.5 28
(1,1/8)
1.1 11.2 28
(1,1/8)
2500 12.9 0.89 9.1 22
(7/8)
0.46 4.7 28
(1,1/8)
0.77 7.9 28
(1,1/8)
0.93 9.5 28
(1,1/8)
0.48 5 35
(1,3/8)
3000 13.25 0.99 10.1 22
(7/8)
0.51 5.2 28
(1,1/8)
0.85 8.7 28
(1,1/8)
10.5 10.6 28
(1,1/8)
0.54 5.5 35
(1,3/8)
18 m Pipe Length 3 m Pipe Length 6 m Pipe Length 10 m Pipe Length 12 m Pipe Length

10. System validation
a) Discharge pressures
After commissioning a Unicla compressor for the rst time, some basic pressure and thermal
loading checks will determine if the operating environment for the compressor is within Unicla
specications, and whether compressor durability is being maximised.
The following chart should be used as a guide for analysing normally acceptable high side (head
pressures) for given ambient . Allow 20% tolerance for humidity above 60% relative humidity.
b) Thermal loading
Excessive thermal loading is the enemy of the modern system, and is often misinterpreted as
being directly attributable to excess pressures. This is not the case.
Excess discharge temperatures may be pressure driven or may be superheated vapours generated
due to inadequate cooling vapour return to the compressor or excessive external thermal loads on
the suction line and/or the compressor.
It is important that all Unicla compressors are operated within a recommend heat range, and all
new applications must be physically tested to ensure this is adhered to.
The following chart shows normal superheat/discharge line temperatures taken from factory test
data. This gives a guideline of what to expect on the discharge line for each Unicla compressor, and
a ‘target’ to aim for (marked in red) in relation to the superheat component for each compressor.
9.
˚C ˚F kPa PSI
15˚C 60 600-800 90-115
18˚C 65 750-950 110-135
21˚C 70 900-1100 130-160
24˚C 75 1050-1300 155-190
27˚C 80 1200-1550 185-220
30˚C 85 1400-1750 200-250
33˚C 90 1500-1900 215-275
35˚C 95 1700-2100 245-300
38˚C 100 1850-2250 265-325
41˚C 105 2000-2400 290-350
44˚C 110 2250-2650 325-385
47˚C 115 2500-2900 370-420
High side pressure chart

To determine the performance of a Unicla UWX compressor in a specific application, the following
Compressor Operation Analysis Report will assist in the collection of the necessary data.
Causes of excessive superheat (discharge)
It is important to note that superheat levels increase as a normal condition
• at higher compressor speeds
• at higher ambient temperature
Abnormal superheat generation may be caused by one or more of the conditions described below
and exaggerated under high heat loads.
Low charge rates
There are two reasons for insufficient flow of refrigerant to the compressor to provide adequate
cooling:
• the ow (volume) is reduced giving less cooling medium
• excessive low side superheating means the suction vapours are no longer cold
The result is not only a low quantity of cooling vapours, but they are no longer cold.
10.
Normal Superheat/Discharge Line Temperature Chart
330, 440 and 550 series compressors
1800 73 15.5 58 1.86 8.9 15
2200 81 15.5 58 1.86 8.9 23
3500 98 15.5 58 1.86 8.9 40
200 series compressors
1800 77 15.5 58 1.86 8.9 19
2000 78 15.5 58 1.86 8.9 20
3500 93 15.5 58 1.86 8.9 35
170 series compressors
1800 75 15.5 58 1.86 8.9 17
2200 78 15.5 58 1.86 8.9 20
3500 83 15.5 58 1.86 8.9 25
150 series compressors
1800 77 15.5 58 1.86 8.9 19
2200 81 15.5 58 1.86 8.9 23
3600 88 15.5 58 1.86 8.9 30
RPM Discharge
Temp ˚C
Condensing
Pressure Kgf/cm2
Condensing
Temp ˚C
Evaporator
Pressure Kgf/cm2
Compressor
Inlet Temp ˚C
Superheat
(discharge line)

11.
11. Other features & performance information
With the compressor placed in environments of low external airflow, such as behind transverse
mounted engines, adequate charge rates must be maintained to ensure adequate compressor
cooling by the refrigerant.
Restricted TX Valves/Orice Tubes:
Will give the same conditions as above.
Inoperable or partially blocked valves/tubes may provide adequate flow under moderate heat load
conditions, but will starve the compressor under high heat load conditions when pump cooling is
most critical.
Poor condensing:
In addition to excessive pressure generation, poor condensing will result in vapour feed to the TX
Valve/Orifice Tube, causing excessive evaporator superheating under high heat loads.
Undersized suction line:
Creates inadequate flow of refrigerant back to the compressor and valuable cooling is not given
to the compressor under high heat load conditions.This can be diagnosed by determining if a
pressure drop is evident in the line. (Refer to section 7 for correct pipe size selection)
Contaminated refrigerants:
May result in loss of compressor cooling, particularly if air or other non condensables, such as
nitrogen, are present in the refrigerant stream.
Note: Excessive discharge line temperatures may be due to either excessive vapour superheating
(as described above) or to excessive discharge line pressures. Refer to the Unicla Service Manual for
further information to assist in diagnosis and rectification if required.
Copyright ©2007
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No part of this document shall be reproduced in whole or in part without the permission of Unicla
International Ltd. This includes reproduction or copies in any form or by any means including
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Unicla International Limited
Unit 1209-1210, 12F Manhattan Centre,
8 Kwai Cheong Rd, Kwai Chung, N.T., Hong Kong
Phone [phone] Fax [phone]
Email: [email protected] Website: www.unicla.hk
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Unicla Cat. No. BO903