Transcript R-410a Refrigerant Cycle Diagnostics

R-410a Refrigerant Cycle
Diagnostics
Mark Stokes
Technical Training Manager
R410a Training
• R410 Refrigerant… Why and When?
• Basic Refrigeration Cycle
• Importance of Airflow
• Installation
• Troubleshooting
Amana® Brand
R-410A Training
R410a Refrigerant
What is it?
Why and when will it be coming?
Definitions of Refrigerants

A refrigerant is a fluid used for heat transfer in a
refrigeration system.

Most refrigerants absorb heat during evaporation at
low temperature and low pressure and reject heat
during condensation at a higher temperature and
higher pressure.
CFC, HCFC,HFC
CFCs (chlorofluorocarbons)
These have a high ozone-depleting potential (ODP) contributing to the
breakdown of the ozone layer, are banned by the Montreal Pro (an
international agreement to protect the earth's ozone layer) and has
been ceased to be manufactured in the European Community (e.g.R11,
R12 and R114.)
HCFCs (hydrochlorofluorocarbons)
These have limited ODP are classified under the Montreal Protocol as
transitional substances and are due to be phased out early this century.
Examples are R22, R123 and R124.
HFCs (hydrofluorocarbons)
These contain no chlorine and therefore have zero ODP ` and in
consequence are not controlled by the Montreal Protocol. Examples are
R410a, R134a and R152a. R134a can be substituted directly, requiring
replacement of some serviceable' components only for R12.
% 1996 CAP
R-22 Phase-Out Timeline
%
100
$20/lb
65%
50
$10/lb
35%
10%
0
1999
2004
No New
Equip. EU
2010
No New
Equip. US
2015
New installations banned 2004 in Europe and 2010 in US
Service end 2010 in Europe and 2020 in US
Europe driving accelerated phase-out dates
All dates could be accelerated
$2/lb
2020
US New Refrigerant Transitions
R-134A
Screw
Chillers
60- 500 Ton
R-22
Commercial
5 to 100 Ton
R-22
R-410A
R-407C
R-410A
R-410A
Residential
1.5 to 5 Ton
R-22
1990
1995
2000
2005
2010
R-410A Facts
Ozone friendly- No Chlorine
Replacement for R-22, NOT a drop in!
Higher Pressure Range-50 to 75%
higher than R-22
Requires Special Lubricants
R-410A
It’s a Blended Refrigerant.
50% R-32 and 50% R-125.
This blend is a near-azeotrope, not a true
azeotrope like R-502.
A true azeotrope is a mixture that maintains
its composition through both the liquid and
vapor phase.
The Future Refrigerant R-410A
Azeotrope/Near Azeotrope
Temperature Glide
Fractionation
R-410A
For a near-azeotrope, the individual refrigerants
evaporate or condense at different temperatures.
The differences between these boiling points with
mixed refrigerants is called: “ TEMPERATURE GLIDE”
When temperature glide is high the refrigerants can
separate during evaporation or condensation.
This changes the composition of the resulting vapor
and liquid.
This separation is called: “FRACTIONATION”
R-410A
Another significant difference between R-410A and
R-22 is its saturation pressure range.
R-410A has a higher pressure range curve than R22.
Remember, R-410A is a near azeotrope that is
subject to some fractionation. At any specific
temperature it has a higher vapor pressure when
saturated.
Components that needed
Redesigned for R-410A
Compressor
Condenser Coil
Filter Drier
Expansion Device
Evaporator
Pressure Switches
Compressors
Copeland ZRS and ZPS
Compressors
We will get further into
these later in the
program.
Pressure Switches
Pressure Switches have to be at higher
settings
Low Pressure R-410A = 50psi
High Pressure R-410A = 610psi
Line Sets
New Line Sets are always recommended, but
required if:
The previous system had a compressor burn out.
The existing line set has oil return traps.
The existing line set has been open to the
atmosphere for an extended time.
The existing line set is larger than or smaller than
the recommended line size for the Amana® R-410A
system.
The existing line set is damaged, corroded, or shows
signs of abrasion/fatigue.
Special Tools Required
Differences in Saturation Pressures
between R-22 and R-410A affects many of
the tools the Technician must use when
Charging and Servicing an R410A
system.
Some of the tools used on R-22 systems
may be unacceptable for use on R410a
systems.
Manifold Gauge Set
Standard Gauges and hoses cannot be used
safely with R410A.
The High Side gauge should have a range of zero
to 800psi.
The Low Side gauge should have a range from 30
inches vacuum to 250psi.
The Low Side gauge should also have a 500psi
retardation feature. This slows the movement of
the gauge needle at higher pressures.
Manifold Gauge Set
Refrigerant Hoses
The 600psi rating of standard
hoses is NOT adequate for
R410A.
Hoses need to be rated for a
800psi working pressure, with
a 4000psi bursting rating.
5 to 1 safety margin is
necessary to prevent
dangerous hose ruptures.
Vacuum Pumps
Pumps used with CFC and
HCFC charged systems may
also be used on R410A systems
as long as the pump is capable
of attaining a vacuum of level of
at least 250 Microns.
Leak Detectors
Leak detectors should be
checked to see that they are
designed to properly detect
R410A.
The detector should have
adjustable sensitivity to allow
leaks to be pinpointed in areas
where background vapor
might cause false readings.
R-410A
The temperature glide of R-410A is very low, thus it
acts very much like a single refrigerant.
Fractionation is very low.
R-410A does not significantly separate in the system
and the composition of the refrigerant has very
minor changes if a leak occurs.
But the fact that some fractionation occurs, means
that charging techniques must be adjusted.
Cylinders
Most R-410A cylinders have an internal dip
tube which allows the feeding of liquid when
the cylinder is in an upright position. They
must be inverted for for vapor flow.
Color is rose (pink).
The cylinder has to have minimum cylinder
pressure requirement of 400 psig rating (DOT
4B400 or DOT 4BW400)
NOTE: Avoid storing R-410A where temperatures will exceed 120° F.
Lubrication
The chemistry of R-410A makes it incompatible
with mineral based lubricants.
Mineral oils typically used with R-22 has
relativity low Miscibility with R-410A.
Miscibility is the ability of an oil to dissolve
uniformly in refrigerant in either the liquid or
vapor state.
Lubrication
The preferred lubricants are the Polyolester or ester
based oils.
Commonly known as POE oils.
POE oils are miscible with any mineral oil traces
that might be in the system.
While miscible, it is very important to remove as
much mineral oil, particulates, and moisture from
existing line sets as possible.
Lubrication
The POE oils are more Hygroscopic than mineral
oils.
This means that they absorb moisture very
rapidly.
Exposure to the atmosphere must be limited.
The oil will break down into acid and alcohol.
Keep the system closed.
Lubrication
Any moisture absorbed by into POE oils cannot
be removed with a vacuum pump-Only a new
drier will work!
Break a recovery vacuum with Nitrogen!
Keep all systems closed until any component
replacements are ready for installation.
Brazing
Should be using at least 2% silver alloy.
Always wear glasses and gloves.
Always purge with nitrogen when brazing.
Protect the service valves with wet rags or heat
sink material.
Scale will get you with POE oils.
Evacuation
Evacuation
Recovery
Yes, you still have to recover the refrigerant.
R-410A does not readily biodegrade, care should
be taken to avoid any releases to the
environment.
The recovery machines used for R-410A must be
designed to prevent cross contamination
between oils and refrigerants..
Use machines certified for use with R-410A.
Recovery
Preferred type is an oil-less compressor model
with a pump down feature for removal of all
refrigerant from the machine after each use.
If an oil bearing compressor is used, the
machine should be restricted to R-410A
refrigerant. The machine must use ester based
oil.
A small leak in an R-410A system can cause:
A. All of the system’s oil to vaporize.
B. All of the system’s oil to be contaminated.
C. Little difference in refrigerant
composition
D. Major changes in refrigerant composition.
The high pressure gauge on an
R-410A manifold gauge set typically has a pressure
range of:
A. 30 to 250 psig.
B. 0 to 500 psig.
C. 0 to 800 psig.
D. 0 to 1200 psig.
The cylinder color for a disposable container of R410A is:
A. Maroon
B. Green
C. Blue
D. Rose
Which of the following is a characteristic of POE
oil:
A. POE has higher wax content than
mineral oil.
B. POE oil will not mix with mineral oil.
C. POE oil is available in only one grade.
D. POE oil is hygroscopic.
To remove moisture from POE oil requires the use
of a(n):
A. High capacity vacuum pump.
B. Low volume vacuum pump.
C. Liquid line filter drier.
D. Oil separator.
The preferred method of charging an
R-410A system is:
A. Liquid charging through the low pressure
valve.
B. Liquid charging through the high pressure
valve.
C. Vapor charging through the low pressure
valve.
D. Vapor charging through the high pressure
valve.
Which of the following recovery machine features
will help prevent cross contamination between
different types of refrigerants and oils?
A. An oil-less compressor and pump down
capabilities.
B. A scroll compressor and an internal drier.
C. A piston style compressor and internal oil
separator.
D. A built in sight glass and moisture indicator.
Under which of the following circumstances may an
R-22 expansion valve be used with R-410A?
A. The R-22 expansion valve has an adjustable
superheat control.
B. The system capacity is less than 48,000 btu’s.
C. The evaporator coil is rated for R-410A.
D. Under no circumstances.
R-410A is combustible if it is mixed with:
A. Oil under a vacuum.
B. Oil under pressure.
C. Pressurized air.
D. Pressurized nitrogen.
QUESTIONS?
any questions?
thank you!