Mitsubishi Electric R410A User manual

A guide to
R410A

The
Natural
Choice

Contents
>>
2
The facts on R410A refrigerant
A brief history of refrigerant
R410A in detail
Ensure correct system evacuation
When using copper pipework
The right tools
Summary
>>
4
6
8
11
12
15

With more manufacturers introducing systems that use
R410A refrigerant, we’ve produced this booklet to explain
the hype that currently surrounds R410A and to present you
with the facts.
Handled correctly, many installers have already realised that R410A refrigerant
has some excellent benefits to offer. However, it’s being portrayed within
the industry as potentially dangerous to use or, it’s being labelled as the only
efficient refrigerant that’s available - which simply isn’t true.
Whilst R410A can provide some small advantages in efficiency, it is
technology itself that is the largest contributor towards the steady increase
in ever important COP’s. A good comparison can be made with cars and
fuel for example: The fact that a car can provide more miles per gallon
today than say, fives years ago, is due to technological advances in the car
rather than the fuel.
The same is true of direct expansion systems, with the need to focus on
efficiency as a whole, not simply the type of refrigerant. How the refrigerant
is used is of paramount importance and good system installation is crucial.
The skills required today, are no different to those that
have always been required and although the
equipment and subsequent numbers may
differ, the need for good practice remains
the same.
Page 2
The
on R410A refrigerant
facts

Page 3
R410A refrigerant
has some excellent
benefits to offer
This guide aims to provide you with
a better understanding of R410A and to
subsequently improve your effectiveness
in today’s air conditioning industry.

Since 1985 it’s been well documented that
the ozone layer surrounding the earth
has been diminishing. Scientific evidence
suggests man-made chemicals are
responsible for creating the hole in the
ozone layer and that they’re likely to add
to global ozone depletion.
Ozone Depleting Substances (ODS) have been
used in many products which take advantages of
their physical properties. For example, Chloro
Fluoro Carbons (CFC’s), have commonly been
used as aerosol propellants and refrigerants.
However, since highlighting that the chlorine in
CFC’s attributes to the demise of the ozone layer,
the ‘Montreal protocol on substances that deplete
the ozone layer’ was negotiated and signed by
24 countries and the European Union in 1987.
The protocol calls for all parties to scale down the
use of CFC’s, halons and other man-made ODS.
Page 4
A brief
history

R22 is a Hydrochlorofluorocarbon (HCFC)
R410A is a Hydrofluorocarbon (HFC)
Systems using R410A refrigerant run at a pressure of approximately 1.6 times that
of similar systems using R22 and the energy efficiency is comparable. The R410A
refrigerant is a 50:50 mixture of R32 and R125. It has a higher direct GlobalW arming
Potential (GW P) than R22 or R407c, but a much lower indirect GW P (CO 2
production at power station).
R407c is a Hydrofluorocarbon (HFC)
R407c is a mix of three refrigerants: R32, R125 and R134a - all of which boil at a
different temperature. R407c has a range or glide of approximately 5°C compared
with R410A which has less than 0.17K. In R407c, R32 provides the capacity,
R125 controls the flammability and R134a reduces the pressure.
Page 5
of refrigerant
R22 is a HCFC refrigerant (comprised of hydrogen, chlorine, fluorine, and carbon)
and is the most common refrigerant used in the world today. T he air conditioning
industry is in the process of moving to HFC refrigerants
(comprised of hydrogen, fluorine and carbon) as they have no chlorine content
and zero O zone Depletion Potential (O DP).

R32 50% R125 50%
Page 6
The phase change of R410A
mixtures takes place at
an almost constant temperature
during the liquefaction or
evaporation process.
The temperature glide
for R410A is less than 0.17K.
Pressure
[bar]
Enthalpy
[kJ/kg]
Sub-Cooling
Superheat
Po
- Compression
- Condenser
- Expansion
- Evaporation
1
2
3
4
2
31
4
Refrigerant Volumic Refrigerating Effect KJ/m3
R410A 6725
R407C 4688
R22 4358
R410A in detail
R410A is a Zeotropic blend of two refrigerants

R410A has zero O zone Depletion Potential (O DP)
W ith the relatively high density and high efficiency of R410A , it is possible to reduce
the size of system components such as condensers, compressors, evaporators and
piping, etc. As operating pressures are higher compared to that of R22 and R407c
,
all system components must all be designed for suitability with R410A.
W hen installing equipment using R410A refrigerant, there are a number of standards
that must be met:
>
An ester oil is used for R410A (as with R407c)
>
It•s impor tant to work with absolute cleanliness
>
BrazingmustbedonewiththeuseofNitrogen(OFN)
>
Thesystemmustbeevacuatedthoroughly(tripleevacuation)
>
A strength test in accordance with local code
>
Thesystemmustalwaysbechargedintheliquidphase
R22 R410A
Suction 60psi 90 to 105 psi
Discharge 260psi 350 to 400 psi
Page 7

To ensure problem-free operation of any air-conditioning system, it is
crucial to carry out thorough evacuation of the system. During the
evacuation any moisture is removed from all of the system components
and the pipework.
The importance of thorough evacuation
It is vitally important to thoroughly evacuate any refrigeration system in
order to prevent the following harmful effects:
>
Any non-condensible product left in the system can cause the
pressure in the condenser to increase and in turn, the
compression temperature to rise.
>
Moisture will result in adverse reactions in the refrigerant circuit.
>
The polyester oils used in the R410A refrigeration systems are
hydroscopic, which means that they absorb moisture from the air.
To prevent chemical reactions in the system, any moisture must
be removed at all costs.
>
Oxygen (air) reacts with the refrigeration unit oil and can lead
to faults such as compressor failure.
To be able to remove moisture from the system it must be evaporated.
The pressure in the pipework must be reduced to such an extent that the
ambient temperature is sufficient to evaporate the moisture.
Page 8
Ensure correct
system evacuation

Page 9
Essential tips for good evacuation
Before evacuating a system, it is essential to check for any potential leaks. Such leaks
may be discovered at brazed or flared joints. Evacuation can only star t once the system
has been properly pressure tested and found to be completely leakproof.
Leak Testing
in 3 easy steps
S t ep 1 45 PSI (N 2) - Test for a minimum of 3 minutes
S tep 2 220 PSI (N 2) - Test for a minimum of 3 minutes
Step 3
450 PSI (N 2) - Test for a minimum of 24 hours (if using R410A)

Triple evacuation
in 6easysteps
S tep 1 Evacuate the system to 1000 microns from both service valves.
To measure the vacuum a vacuum gauge must be used at
all times - do not use a system manifold gauge
S t ep 2 Break the vacuum with O FN to 14 PSIG
S tep 3 Evacuate to 500 microns
S tep 4 Repeat Step 2
S t e p 5 Evacuate to the lowest pressure that the pump will achieve
(200 microns for a minimum of 1 hour)
S tep 6 T he rise test must then be carried out for a minimum of 30 minutes
Page 10

Page 11
Use only copper pipes with the correct wall thickness -
please refer to your usual copper pipe supplier for detail
Make sure you cut the copper pipe with a proper pipe cutter only
Remove any burrs with the utmost care
Make sure that no swarf or other impurities get into the piping
When brazing make sure that Nitrogen (OFN) is used at all times
Brazed joints must be bare and clean
The importance of correct brazing
Brazed joints should only be made using Nitrogen
(OFN) as without it carbon deposits are left on the
pipe surface. The carbon deposits are then washed
off of the surface of the pipe when the refrigerant
is circulated and it then travels with the
refrigerant.
Carbon deposits can cause the refrigerant
and refrigeration unit oil to decompose.
This is likely to result in operation
defects and warranty will become null
and void.
When using
copper
pipework
>
>
>
>
>
>

Page 12
The right tools are required in to enable the
refrigeration system to be properly
evacuated and dried.
These include:
>
R410A Manifold Gauges
>
Flaring Tool
>
Torque Wrench
>
Vacuum Pump
>
Refrigerant Weighing Scales
The right tools

Page 13
R410A Refrigerant Manifold
A solid manifold gauge specifically used
for R410A.
M anifo ld gauge s w ith sight gauge s
should never be used due to the higher
operating pressures, unless specified
for use on R410A.
N itrogen Pressure Gauge
A highe r r ange N it r o ge n R egulato r
must be used due to the higher
pressure testing requirements
when strength testing to conform
with local code.
Vacuum G auge
Vacuum Pump
A Vacuum pump of sufficient quality and
working order to be used to pull the
correct vacuum to negate any moisture
being present in the system (pump oil
needs to be regularly changed).
T he pressure gauge
*T he refrigerant manifold gauges are not suitable for measuring vacuum.
A vacuum gauge to be used to provide an
accurate evactuation level is required

Page 14
FlaringTool
A suitable Flaring tool to be used so as
not to compromise the integrity of the
copper when flared.
Torque W rench
Torque wrenches must be used at all
times to tighten flares in accordance with
manufacturers guidelines.
O xygen free nitrogen for brazing
O FN to be used at all times during
brazing to prevent oxidation within the
copper pipewor k.
O xygen free nitrogen for strength and leak test
O FN to be used for strength and leak
testing with the higher pressure regulator.
Refrigerant charging weighing scales
Any additional refrigerant required for
the installed system must be weighed in
the liquid phase using charging scales.
Suitable vacuum measuring gauges
To determine accurately the pressure in the system and whether the desired vacuum has been
attained, a vacuum or torr meter is indispensable. A professional evacuation requires such
an instrument.

Page 15
To get the best from R410A
>
Use the correct tools
>
A dhering to local code
>
Strength test to 1.3 x Ps (623 PSI)
>
Leak test to 1.0 x Ps (478 PSI)
>
O bserve regulations (Health & Safety at work, pressure equipment etc.)
>
Use correct copper pipework with appropriate wall thickness
>
Follow good working practice at all times (N itrogen brazing, proper evacuation, etc.)
The benefits of working with R410A
>
Higher pressures
>
More efficient
>
Smaller pipe diameters
>
L o wer r efr iger ant char ge
>
Small system size per kW
>
Higher heat transfer coefficient
>
Very small temperature glide <0.17k
>
HFC zeotropic mixture of HFC -32 and HFC -125
>
High pressure - narrow glide
>
Hydrofluorocarbon blend with zero O DP
>
Lower indirect global warming potential (C O 2production at power station)
than R22 and R407c
If you follow the guidelines contained within and carr y out good refrigeration
practices at all times, then working with R410A will be no different from working with
previous refrigerants.
Know it and use it!
Summar y
>>

Page 16
All text, illustrations, diagrams and examples in this
guide are only intended to help with the handling
and proper use of the refrigerant R410A. The
information contained in this brochure has been
carefully researched and checked and is considered
correct at time of going to press.
Should you have any further queries regarding
installation and operation of the equipment
described in this guide, please contact us at:
Mitsubishi Electric Europe
Air Conditioning Systems Division
Travellers Lane, Hatfield, Hertfordshire, AL10 8XB
Tel: [phone]
Fax: [phone]