1 PRECAUTIONS FOR DEVICES THAT USE R407C REFRIGERANT
11
Caution
Do not use the existing refrigerant piping.
• The old refrigerant and refrigerator oil in the existing
piping contains a large amount of chlorine which may
cause the refrigerator oil of the new unit to deteriorate.
Use refrigerant piping made of C1220 (CU-DHP) phosphorus deoxidized copper as specified in the *JIS
H3300 “Copper and copper alloy seamless pipes and
tubes”. In addition, be sure that the inner and outer
surfaces of the pipes are clean and free of hazardous sulphur, oxides, dust/dirt, shaving particles, oils,
moisture, or any other contaminant.
• Contaminants on the inside of the refrigerant piping
may cause the refrigerant residual oil to deteriorate.
*JIS: Japanese Industrial Standard
Store the piping to be used during installation indoors
and keep both ends of the piping sealed until just
before brazing. (Store elbows and other joints in a
plastic bag.)
Use a vacuum pump with a reverse flow check valve.
• The vacuum pump oil may flow back into the refrigerant cycle and cause the refrigerator oil to deteriorate.
Do not use the following tools that have been used
with conventional refrigerants.
(Gauge manifold, char ge hose, gas leak detector, reverse flow check valve, refrigerant charge base,
vacuum gauge, refrigerant recovery equipment)
• If the conventional refrigerant and refrigerator oil are
mixed in the R407C, the refrigerant ma y deteriorated.
• If water is mixed in the R407C, the refrigerator oil ma y
deteriorate.
• Since R407C does not contain any chlorine, gas leak
detectors for conv entional refrigerants will not react to
it.
Do not use a charging cylinder.
• Using a charging cylinder may cause the refrigerant
to deteriorate.
• If dust, dirt, or water enters the refrigerant cycle, deterioration of the oil and compressor trouble may result.
Use ester oil, ether oil or alkylbenzene (small amount)
as the refrigerator oil to coat flares and flange connections.
• The refrigerator oil will degrade if it is mixed with a
large amount of mineral oil.
Use liquid refrigerant to seal the system.
• If gas refrigerant is used to seal the system, the composition of the refrigerant in the cylinder will change
and performance may drop.
Do not use a refrigerant other than R407C.
• If another refrigerant (R22, etc.) is used, the chlorine
in the refrigerant may cause the refrigerator oil to deteriorate.
Be especially careful when managing the tools.
• If dust, dirt, or water gets in the refrigerant cycle, the
refrigerant may deteriorate.
If the refrigerant leaks, recover the refrigerant in the
refrigerant cycle, then recharge the cycle with the
specified amount of the liquid refrigerant indicated
on the air conditioner.
• Since R407C is a nonazeotropic refrigerant, if additionally charged when the refrigerant leaked, the composition of the refrigerant in the refrigerant cycle will
change and result in a drop in performance or abnormal stopping.
–1–
[1]Storage of Piping Material
(1) Storage location
Store the pipes to be used indoors. (Warehouse at site or owner’s warehouse)
Storing them outdoors may cause dirt, waste, or water to infiltrate.
(2) Pipe sealing before storage
Both ends of the pipes should be sealed until immediately before brazing.
Wrap elbows and T’s in plastic bags for storage.
* The new refrigerator oil is 10 times more hygroscopic than the conventional refrigerator oil (such as Suniso). Water
infiltration in the refrigerant circuit may deteriorate the oil or cause a compressor failure. Piping materials must be stored
with more care than with the conventional refrigerant pipes.
–2–
[2]Piping Machining
Use ester oil, ether oil or alkylbenzene (small amount) as the refrigerator oil to coat flares and flange connections.
Use only the necessary minimum quantity of oil !
Reason:
1. The refrigerator oil used for the equipment is highly hygroscopic and may introduce water inside.
Notes:
•Introducing a great quantity of mineral oil into the refrigerant circuit may also cause a compressor failure.
•Do not use oils other than ester oil, ether oil or alkylbenzene.
–3–
[3]Necessary Apparatus and Materials and Notes on Their Handling
The following tools should be marked as dedicated tools for R407C.
<<Comparison of apparatus and materials used for R407C and for R22>>
Apparatus UsedUseR22R407C
Gauge manifoldEvacuating, refrigerant fillingCurrent product
Charging hoseOperation checkCurrent product
Charging cylinderRefrigerant chargingCurrent productDo not use
Gas leakage detectorGas leakage checkCurrent productShared with R134a
Refrigerant collectorRefrigerant collectionR22For R407C use only
Refrigerant cylinderRefrigerant fillingR22Identification of dedi-
cated use for R407C:
Record refrigerant
name and put brown
belt on upper part of
cylinder.
Vacuum pumpVacuum dryingCurrent productCan be used by attach-
ing an adapter with a
check valve.
Vacuum pump with a check valveCurrent product
Flare toolFlaring of pipesCurrent product
BenderBending of pipesCurrent product
Application oilApplied to flared partsCurrent productEster oil or Ether oil or
Alkybenzene (Small
amount)
Torque wrenchTightening of flare nutsCurrent product
Pipe cutterCutting of pipesCurrent product
Welder and nitrogen cylinderWelding of pipesCurrent product
Refrigerant charging meterRefrigerant chargingCurrent product
Vacuum gaugeChecking the vacuum degreeCurrent product
Symbols:
Tools for R407C must be handled with more care than those for con v entional refrigerants. They must not come into contact
with any water or dirt.
To be used for R407C only. Can also be used for conventional refrigerants.
–4–
[4]Brazing
No changes from the conventional method, but special care is required so that foreign matter (ie. oxide scale, water, dirt,
etc.) does not enter the refrigerant circuit.
Example: Inner state of brazed section
When non-oxide brazing was not usedWhen non-oxide brazing was used
Items to be strictly observed:
1. Do not conduct refrigerant piping work outdoors on a rainy day.
2. Apply non-oxide brazing.
3. Use a brazing material (Bcup-3) which requires no flux when brazing between copper pipes or between a copper pipe
and copper coupling.
4. If installed refrigerant pipes are not immediately connected to the equipment, then braze and seal both ends of them.
Reasons:
1. The new refrigerant oil is 10 times more hygroscopic than the con ventional oil. The probability of a machine failure if
water infiltrates is higher than with conventional refrigerant oil.
2. A flux generally contains chlorine. A residual flux in the refrigerant circuit may generate sludge.
Note:
•Commercially available antioxidants may have adverse effects on the equipment due to its residue, etc. When
applying non-oxide brazing, use nitrogen.
–5–
[5]Airtightness Test
No changes from the conventional method. Note that a refrigerant leakage detector for R22 cannot detect R407C leakage.
Halide torchR22 leakage detector
Items to be strictly observed:
1. Pressurize the equipment with nitrogen up to the design pressure and then judge the equipment’s airtightness, taking
temperature variations into account.
2. When investigating leakage locations using a refrigerant, be sure to use R407C.
3. Ensure that R407C is in a liquid state when charging.
Reasons:
1. Use of oxygen as the pressurized gas may cause an explosion.
2. Charging with R407C gas will lead the composition of the remaining refrigerant in the cylinder to change and this
refrigerant can then not be used.
Note:
•A leakage detector for R407C is sold commercially and it should be purchased.
[6]V acuuming
1. Vacuum pump with check valve
A vacuum pump with a check valve is required to prevent the vacuum pump oil from flowing back into the refrigerant
circuit when the vacuum pump power is turned off (power failure).
It is also possible to attach a check valve to the actual vacuum pump afterwards.
2. Standard degree of vacuum for the vacuum pump
Use a pump which reaches 0.5 Torr (500 MICRON) or below after 5 minutes of operation.
In addition, be sure to use a vacuum pump that has been properly maintained and oiled using the specified oil. If the
vacuum pump is not properly maintained, the degree of vacuum may be too low.
3. Required accuracy of the vacuum gauge
Use a vacuum gauge that can measure up to 5 Torr . Do not use a general gauge manifold since it cannot measure a
vacuum of 5 Torr.
4. Evacuating time
• Evacuate the equipment for 1 hour after –755 mmHg (5 Torr) has been reached.
• After envacuating, leave the equipment for 1 hour and make sure the that vacuum is not lost.
5. Operating procedure when the vacuum pump is stopped
In order to prevent a backflow of the vacuum pump oil, open the relief valve on the vacuum pump side or loosen the
charge hose to drawn in air before stopping operation.
The same operating procedure should be used when using a vacuum pump with a check valve.
–6–
[7]Charging of Refrigerant
R407C must be in a liquid state when charging, because it is a non-azeotropic refrigerant.
For a cylinder with a syphon attachedFor a cylinder without a syphon attached
Cylin-
Cylin-
der
Cylinder color identification R407C-GrayCharged with liquid refrigerant
Valve
R410A-Pink
der
Valve
Liquid
Liquid
Reasons:
1. R407C is a mixture of 3 refrigerants, each with a different evaporation temperature. Therefore, if the equipment is
charged with R407C gas, then the refrigerant whose evaporation temperature is closest to the outside temperature is
charged first while the rest of refrigerants remain in the cylinder.
Note:
•In the case of a cylinder with a syphon, liquid R407C is charged without turning the cylinder up side down. Check the
type of cylinder before charging.
–7–
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