Medium and Low Temperature Retrofit from
R502 to R404A/R507
Application Bulletin 125
Application Bulletin
Number:
Release EN:
Date:
Revision EN:
Date:
125
C18810
10/20/95
Z27301
10/2/15
Subject: Medium and Low Temperature Retrofit from R502 to R404A/R507
These are general guidelines only and in no way should they replace, contradict or otherwise take precedence
over any local, state or federal law or regulation pertaining to the recovery, reclamation, and recycling of refrigerants.
With the phase-out of CFC’s, existing refrigeration equipment will need to be replaced with new equipment or retrofitted with new components (including the compressor) that are approved for use with the new refrigerant and
their lubricants. Using the procedures described below, existing R502 systems can be retrofitted for use with
R404A or R507, allowing them to continue in service for the remainder of their useful life. Bristol Compressors
does not recommend the changeover of CFC refrigerants to HFC’s in systems that are operating and have no
leaks.
R404A is a near-azeotropic blend of refrigerants of the following composition:
R125
R143a
R134a
44%
52%
4%
R507 is an azeotropic blend of refrigerants of the following composition:
R125
R143a
50%
50%
New Medium and Low Temperature R404A/R507 Compressors are identified by the number 6 in the second
digit of the model number (example: L61B562BBC). These compressors are factory oil charged with polyolester
(POE) lubricant and employ an improved lubrication system which are required for the new refrigerant.
Bristol’s lubricant approved for use with R404A and R507 is Polyolester Mobil EAL Arctic 22A. The use of any
other lubricant may void the compressor warranty. The amount of oil charge for each model is listed in the individual compressor specification.
SYSTEM DESIGN
1.0
Refrigerant Metering Devices
The performance of each system is very dependent on the proper operation of each metering device. Devices such as solenoid valves, capillary tubes, fixed orifice valves, and expansion valves can perform differently if they are not correctly adjusted or properly sized. For example, the port size of a valve may not be
correct for the new refrigerant density. Each valve and metering device manufacturer should be consulted,
along with the system’s manufacturer, to ensure all components will work properly in the presence of the
new refrigerant and lubricant.
2.0
Filter Driers
The proper selection of a system’s filter drier is very important. Some filter driers may not be suitable for
R404A/R507 refrigerant and polyolester lubricant. Therefore, the original equipment manufacturer should
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be contacted for the proper filter drier selection. It is important to replace the filter drier any time the refrigerant or lubricant in a system is changed. Specifically, Bristol Compressors requires a new suction line filter
drier be installed during any compressor replacement. Maintaining good system performance, reliability
and cleanliness is closely linked to proper filter drier operation.
3.0
Controls
The proper operation of many types of refrigeration equipment requires that the control systems function
correctly. The control system could be pressure controls, temperature controls, timing devices, or sophisticated electronic controls. Changing to R404A/R507 refrigerant and polyolester lubricant in a system could
adversely affect these control systems. Each equipment manufacturer should be consulted to ensure each
control system will operate correctly with the R404A/R507 refrigerant/polyolester lubricant combination.
Changes most likely will have to be made for continued good equipment performance. These changes
could involve adjusting temperature or pressure set points to new values or replacing the control system
with a newly designed unit.
4.0
Explanation of R404A/R507 vs. R502 Condenser and Evaporator Temperature/Pressure Graphs
Pressure versus temperature charts and graphs are included on pages 3 through 5 as a general information
guideline. More detailed saturated property tables can be obtained from the chemical manufacturer and
should be used when conducting system retrofits. The graphs are intended to represent the pressures that
R404A/R507 delivers versus R502 at the equivalent saturated evaporator and condenser temperatures.
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Saturated Properties of R404A, R507 and
R502 Pressure vs. Temperature Graph
Pressure (Psia)
Condenser Pressure vs. Temperature
375
365
355
345
335
325
315
305
295
285
275
265
255
245
235
225
215
205
195
185
175
165
155
145
135
125
R507
R502
R404A SAT VAPOR
R404A SAT LIQUID
80
90
100
110
120
130
Condenser Temperature (°F)
FIGURE # 1
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Saturated properties of R404A, R507 and R502
Pressure vs. Temperature Graph
Evaporator Pressure vs. Temperature
140
R507
R502
120
R404A SAT VAPOR
R404A SAT LIQUID
Pressure (Psia)
100
80
60
40
20
0
-20
-10
0
10
20
30
40
50
Evaporator Temperature (°F)
FIGURE # 2
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TABLE 1
Pressure-Temperature Chart
Pressure
(1)
Saturated Vapor Temperature °F
Pressure
Saturated Vapor Temperature °F
(psig)
R404A(1)
R507
R502
(psig)
R404A(1)
R507
R502
0
-50
-51
-50
46
12
10
15
2
-45
-47
-45
48
14
11
16
4
-41
-43
-40
50
15
13
18
6
-37
-39
-36
52
17
15
20
8
-33
-35
-32
54
19
16
21
10
-30
-32
-29
56
21
18
23
12
-26
-29
-25
58
22
19
24
14
-23
-26
-22
60
24
21
26
16
-20
-23
-19
62
25
22
28
18
-17
-20
-16
64
26
24
29
20
-15
-17
-13
66
27
25
30
22
-12
-15
-11
68
29
26
32
24
-10
-12
-8
70
30
28
33
26
-8
-10
-6
72
32
29
34
28
-5
-8
-3
74
33
30
36
30
-3
-5
-1
76
34
32
37
32
-1
-3
1
78
35
33
38
34
1
-1
3
80
36
34
40
36
3
1
5
85
40
37
43
38
5
3
7
90
43
40
46
40
7
5
9
95
45
43
49
42
9
6
11
100
48
46
51
44
10
8
13
105
51
48
54
Saturated Vapor Temperature (Dew Point)--The temperature (at a given pressure) at which
the last drop of liquid R404A/R507 has boiled. It is also the temperature (at a given pressure)
where condensation begins. Above this temperature (at the same pressure), the refrigerant
is superheated vapor.
NOTE: For R404A/R507 the mean evaporator temperature where a change of state occurs is approximately 1°F below the saturated vapor temperature. For example, at a saturated vapor
temperature of 11°F, the mean evaporator temperature is approximately 10°F.
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5.0
Maximum Continuous Current (MCC) Data
Extensive testing has been done at maximum continuous current (MCC) test conditions with R404A/R507 and
R502 refrigerant on many different displacement compressors. The MCC values of the compressors did not
change from the published R502 values when R404A or R507 refrigerant was utilized.
6.0
Retrofit Procedure
Summarized below are the recommended procedures for retrofitting an R502 system to R404A or R507:
6.1
Compatibility. Consult the original equipment manufacturer of the system components for their recommendation on the following:
-
Plastics compatibility
Elastomers compatibility
Lubricant (viscosity, manufacturer, additives)
Solid core driers: Check with drier manufacturer for recommendations
6.2
If compressor has failed:
a. Determine reason for system/compressor failure and correct
b. Recover refrigerant (see step 6.4)
c. Remove compressor (see step 6.5)
d. Measure lubricant remaining in compressor - should be greater than 95% of original charge to minimize removal efforts in step (e)
e. Assure removal of residual levels of original lubricant (must be less than 5%)
- Purge system heat transfer components using high pressure inert gas (e.g., nitrogen)
- Disconnect and purge line sets, or any other component that could trap lubricant (e.g., oil separator, valves, etc.)
- Large system/long line sets may require up to three (3) oil changes after replacing compressor
f. Go to 6.6
6.3
If compressor has not failed:
a. Run at reference condition and record on Data Sheet (see Appendix 2) which will be used to confirm
R404A or R507 charge requirements
b. Run system at a high flow condition (highest suction pressure) for 10 - 15 minutes for optimum lubricant pick-up/return to compressor
c. Go back to step 6.2, item (b) through (f)
6.4
Remove R502 charge. Remove refrigerant and collect in a recovery cylinder using a recovery device
capable of pulling 10 - 20 in. Hg vacuum. If the correct R502 charge size for the system is not known,
weigh the amount of refrigerant removed. The initial quantity of R404A or R507 charged in the system
will be determined from this weight.
6.5
Remove compressor. The compressor must be removed from system since it will not be compatible with
HFCs/POE lubricant.
6.6
Replace filter drier. Replace filter drier with one approved for use with R404A or R507 refrigerant/
polyolester lubricant.
6.7
Install compressor. Using normal service practices, install one approved for R404A or R507
refrigerant/polyolester lubricant.
CAUTION: Do not leave compressor or system open to atmosphere longer than 15 minutes
maximum. Polyolester lubricants are at least 100 times more hygroscopic (ability to absorb
moisture) than mineral oils. It is almost impossible to remove the moisture absorbed by the
lubricant even with heat and vacuum.
6.8
Leak check system. Use normal service practices. If a leak detector is used, consult the leak detector manufacturer for unit’s sensitivity to R404A and R507.
6.9
Evacuate. Use normal service practices to remove air and other non-condensables in the system,
evacuate to at least 200 microns.
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6.10 Charge system with R404A or R507. To ensure that the proper refrigerant composition is charged in
the system, it is important that liquid only be removed from the charging cylinder using R404A. R507
is an azeotrope and does not require charging in the liquid phase. Once removed from the cylinder,
R404A can be charged to the system as vapor as long as all of the refrigerant removed from the cylinder is transferred to the system.
Due to the liquid density difference of R404A and R507 versus R502, the refrigeration system will require less weight of R404A and R507 than R502. The optimum charge will vary depending on the
operating conditions, size of the evaporator and condenser, size of receiver (if present), and length of
pipe or tubing runs in the system. For most systems, the optimum charge will be 90 - 95% by weight
of the original R502 charge. It is recommended that the system be initially charged with about 90% by
weight of the original R502 charge (refer to section 6.4).
Add the initial charge to the liquid line of the system with the compressor not running. When the system and cylinder pressures are equal, start the compressor and meter the remainder of the refrigerant
into the suction line of the system. Since some compressors may be damaged if liquid refrigerant enters the suction side of the compressor, it is important to charge the refrigerant slowly into the suction
line to allow it to vaporize before it enters the compressor. A throttling valve can be used to ensure
that the liquid is converted to vapor prior to entering the system.
6.11 Charge adjustment. Allow the system to run until conditions stabilize. Add additional R404A or R507
in small amounts until the system conditions reach the desired levels (refer to data recorded in step
6.3). Be sure to charge by evaporator/condenser temperatures, since the pressures will be higher at
the temperatures equal to R502. Total charge should not exceed original R502 charge levels.
6.12 Label components and system. After completion of retrofit, label the system and the converted components to identify the type of refrigerant and lubricant, so proper service will be performed in the future.
Attached is a Retrofit Checklist (Appendix 1) for R404A and R507 to assist you in the retrofit process
and a System Data Sheet (Appendix 2) to record the system operating conditions for your records.
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Appendix 1
Checklist for R404A/R507 Retrofit
1. Consult the original equipment manufacturer of the system components for their recommendation concerning compatibility and their retrofit procedures in order to sustain warranty.
2. If compressor is operable, run high flow condition (highest suction pressure) for 10 - 15
minutes to maximize oil return to compressor.
3. Remove R502 charge from system (need 10-20 in. Hg vacuum to remove charge). Use recovery cylinder --Do not vent to atmosphere-4. Replace filter drier with new filter drier approved for use with R404A/R507.
- Loose fill driers: Use XH7 or XH9 desiccant or equivalent.
- Solid core driers: Check with drier manufacturer for recommendation.
5. Replace compressor with one approved for usage with R404A/R507
- Measure and record oil remaining in old compressor
- Residual lubricant should be less than 5% by weight of the total lubricant used in system
6. Leak check system using normal service practices.
7. Evacuate with vacuum pump (200 microns minimum).
8. Charge system with R404A/R507.
- Initially charge 90% by weight of original equipment manufacturer specified R502 charge.
- Amount of refrigerant charged: _______
9. Start up equipment and adjust charge until desired operating conditions are achieved.
- If low on charge, add in increments of 2 - 3% of original R502 charge.
- Amount of refrigerant charged: _______
10. Total Refrigerant Charged (add 8 and 9) _______
- Should not exceed original R502 charge level
11. Label components and system for type of refrigerant (R404A or R507) and lubricant
(polyolester oil).
12. Conversion is complete!!
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Appendix 2
SYSTEM DATA SHEET
Type of System/Location:
Equipment Mfg.:
Compressor Mfg.:
Model No.:
Model No.:
Serial No.:
Serial No.:
Original Lubricant:
Type/Mfg.:
Charge Size:
New Lubricant:
Type/Mfg.:
1st Charge Size:
2nd Charge Size:
Additional Charge Size:
Drier Mfg.:
Drier type (check one):
Model No.:
Loose Fill:
Solid Core:
Condenser Cooling Medium (Air/Water):
Expansion Device (check one):
Capillary Tube:
Expansion Valve:
If Expansion Valve:
Manufacturer:
Model No.:
Control/Set Point:
Location of Sensor:
Other System Controls (e.g.: head press control); Describe:
(circle units used where applicable)
R502 Data
R404A or R507 Data
Date/Time
Refrigerant
Charge Size Lb.
Ambient Temperature (°F/°C)
Relative Humidity
Compressor:
Suction Temperature (°F/°C)
Suction Pressure psig
DischargeTemperature (°F/°C)
Discharge Pressure psig
Indoor Temperature (°F/°C)
Evaporator:
Refrigerant Inlet Temperature (°F/°C)
Refrigerant Outlet Temperature (°F/°C)
Coil Air/H 2O In Temperature (°F/°C)
Coil Air/H 2O Out Temperature (°F/°C)
Refrigerant Temperature @ Superht. Ctl. Pt. (°F/°C)
Condenser:
Refrigerant Inlet Temperature (°F/°C)
Refrigerant Outlet Temperature (°F/°C)
Coil Air/H 2O In Temperature (°F/°C)
Coil Air/H 2O Out Temperature (°F/°C)
Exp. Device Inlet Temperature (°F/°C)
Motor Amps
Run/Cycle Time
Comments:
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Application Bulletin 125
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Release EN Number C18810
Release Date 10/20/95
Revisions
D00905
Revision Z27301
2/9/96
Z27301
10/2/15
Application Bulletin 125
Page 11