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Forane®427A (R427A)系统改造指南

使用Forane® 427A (R427A) — the Easy R-22 RetrofitTM改造您的R-22系统时,请遵循下列指南。如需获取其他支持和故障排除方法,请与我们的客户服务部联系((800) 245-585)。如有任何有关R-22系统改造方面的技术问题,请您拨打我们的技术服务热线:(800) 738-7695。

第1步:确定基准性能

检查系统是否有泄漏,确定是否需要进行任何修理。基于出厂R-22系统充注量运行设备,并使用阿科玛的“系统改造数据表”记录性能参数。

第2步:回收系统里的R-22

回收现有的R-22制冷剂(切勿排放到大气中),确保不要与其他制冷剂气体混合。记录回收的制冷剂重量。

第3步:检查润滑油

润滑油可能不需要更换,但我们还是建议您将润滑油更换为POE,以确保实现最佳性能。很重要的一点是必须确认润滑油的品质,检查润滑油是否有水分、酸度、金属碎屑或沉淀物。如果润滑油不符合所需的规格,建议将系统里的润滑油替换成POE油。系统配备复杂配管或储液器的系统可能阻碍正常回油,因此建议添加或更换为POE油。对于通过将润滑油从油槽底部抽出的方式对压缩机轴承进行润滑的系统,比如配备Danfoss SM涡旋压缩机和Trane® 3-D®压缩机的系统,也建议将润滑油更换为POE油。

第4步:更换过滤干燥器滤清器干燥器和密封圈

更换过滤干燥器,如有必要,更换弹性密封圈和垫圈,比如针阀阀芯的密封圈。

第5步:系统检漏,并将系统排空

使用干燥氮气对系统做保压测试,以确定系统是否有泄漏,压力需保持在系统安全压力极限之下。如有必要,检所有漏点。抽到最少500微米的真空度(0.5毫米汞柱),确保其保持真空。如果系统不能保持真空,漏点可能仍然存在。

第6步:给系统充注Forane® 427A (R427A)

仅以液体形式充注制冷剂,小心不要损坏压缩机。初始重量应当为R-22初始加注量的大约95%,必要时,加注至100%。

第7步:启动系统并检查性能

运行系统并记录系统性能,注意过热度和过冷度。调节TXV设定值和/或制冷剂充注量,以实现所需的过热度。低压开关设定点也可能需要调节。

第8节:为系统张贴标签

为系统妥善张贴标签,注明已使用Forane® 427A (R427A)进行系统改造。如需获取Forane® 427A (R427A)系统改造标签,请拨打阿科玛客户服务热线:(800) 245-5858。

Other import details

Always charge less than the original R-22 charge.  Charge 90% of the original R-22 charge, let the system run for twenty minutes, then add refrigerant, if needed.  The flow rate of Forane® 427A is within 8% of R-22.  Rarely will an adjustment of the expansion device be needed, in most systems.  Large systems running EEVs will need to be programmed for the P/T characteristics of R-427A.   

 

Pressure Temperature (P/T) Chart:  All refrigerants have a respective P/T chart.  Technicians can download the Forane® PT App (found in iTunes and GooglePlay), containing all Forane refrigerants (see QR codes below).   Blended gases have two columns:  Vapor and liquid.  Use the vapor column for calculating superheat and the liquid column for subcooling.  Use subcooling for systems utilizing a TXV.

 

Charging to sight glass:  Unlike R-22, which is a single component refrigerant, R-427A is blended from four component refrigerants:  R-32, R-125, R-143a, and R-134a.  Each component has a different boiling point, which equates to a 9o glide, when combined in ratios specific to R-427A.  Seeing bubbles in a sight glass might not be indicative of a low charge, rather it could be a consequence of the glide.  Therefore, charging by superheat and subcooling is the only way to attain the optimal charge.

 

“Topping off”:  Forane® 427A refrigerant is a near-azeotrope blend and could fractionate.  The rate of fractionation is dependent of several factors:  Running vs. dormant and/or liquid vs. gas.  Leaks will fractionate at different rates.  If the system leaked out more than half of its charge, Arkema suggests you recover the remaining gas and charge the system with new liquid Forane® 427A.  The consequences of fractionation could be less than optimal performance, and the actual P/T readings will not match the P/T Chart.

 

Mixing refrigerants with R-22:  A technician is not supposed to mix refrigerants for three reasons.

  • EPA 608 prohibits mixing refrigerants in the field. 
  • The original R-22 will be contaminated with the added refrigerant.
  • The P/T readings may not match either P/T chart.

 

There are no use restrictions on R-22 in the USA.  The phase down of R-22 production ends in 2020, however usage can continue until the R-22 supply is completely exhausted.  Some systems might benefit by continuing to operate on R-22.  Flooded evaporators and recirculation systems will be difficult to retrofit to a blended refrigerant.  Arkema recommends continuing to use R-22 in these applications.   

NOTES:

* Forane® 427A is intended as a retrofit in systems originally designed for R-22.  Therefore, how the system was running on R-22 will be a guide or target for how the system should run on R-427A.  Compared to R-22, expect 0-5 psi lower on the suction side and 0-10 psi higher on the discharge.  It could be higher on high load/high ambient days.  

** Forane® 427A is compatible with MO & AB.  However, unlike R-22, it is not completely miscible (ability to form one solution).  Therefore, it is recommended to either add 20% additional POE or change over to POE, where circumstances warrant.  Oil return could be inhibited in systems with long complex line sets and risers feeding compressor located > 5’ above the evaporator.  Tandem compressors without oil separators and chillers with large diameter suction lines will require a complete change to POE to assure proper oil return.  Layering of liquid oil and liquid refrigerant might occur in receivers, which could prove problematic for oil return.  Poor oil quality could also affect oil return and cause damage to the system.  Contaminated systems should be flushed, and oil replaced with new POE.  Below is a guide to when you should be concerned with oil return using MO/AB with R-427A.  Be aware that compressor age, type, and condition could also impact oil return. Trane 3-D, Danfoss SM and all screw compressors will require a complete oil change to POE.   

               

                       NO OIL CHANGE

  1. Evaporator above compressor
  2. Standard line set with minimal bends
  3. Package units and close coupled systems
  4. Systems utilizing oil separators

               Add or Change to POE

  1. Compressor above the evaporator > 5’
  2. Long complex line sets
  3. Tandem compressors, without an oil separator
  4. Large diameter suction lines > 3”
  5. Trane 3D scrolls & Danfoss SM compressors
  6. Systems with receivers

 

*** If you add or change over to POE, you must install a new filter dryer.  POE will act like a solvent and loosen dirt/grime within the system.  POE oil is also hydroscopic.  Pulling deep vacuums to 500 microns and installing new filter dryers are highly recommended.

**** Elastomeric seals can swell as a result of absorbing refrigerant.  Different materials (different refrigerants) can be absorbed at different rates or to different amounts, and the extent of swelling will be different.  The swelling is taken into account during the design of HVAC systems.  HCFC refrigerants, like R-22, have chlorine.  By their nature, chlorinated refrigerants will be more easily absorbed by elastomer materials than non-chlorinated refrigerants like (HFC) R- 427A. The seals/gaskets will not swell as much compared to R-22.   Additionally, pulling a vacuum could further deform the seal.  Arkema recommends replacing seals and gaskets, when retrofitting any R-22 system. In many HVAC systems, the Schrader core is only external seal that needs to be replaced.  

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