TECHNICAL SUPPORT At MSI our commitment to service continues after the sale. Our Tech Services department is standing by to provide you with the technical support you need when you need it. And if necessary we can meet you on the job site to show you first hand what needs to be done.
Contact Tech Service:
1-888-967-4832
PARTS To support our Dealers we stock a wide variety of OEM service parts for the equipment lines we carry as well as a complete selection of aftermarket parts, at all locations. If we don't have what you need special orders are no problem, and we carry a wide selection of quality tools for the HVAC technician.
EDUCATION MSI proctors both NATE and EPA exams and also provides regular training opportunities to help you sharpen your skills while keeping up with our changing industry. Check with your local branch for upcoming events or browse our events and training calendar.
Technical Reference
Armstrong Specs
Ducane Specs
Allied Commercial Specs
EPA R22 Phase Out FAQ
R22 - R410A Conversion
Deep Vacuum Process
Industry links
NATE Certification
RSES
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R22 - R410A Conversion
R410A and R22 refrigerants are not interchangeable. They can not be mixed in one AC system or used in a system that is not specifically designed for one or the other. R410A and R22 also use different lubricating oils that are not compatible, so when replacing an R22 system with an R410A system the best option is to remove and replace the condenser, indoor coil, and lineset.
When the lineset is inaccessible and can not be replaced it must be flushed to remove all residual oils and contaminants. Extra effort should be taken when flushing a lineset that includes traps and low spots, or if the previous system experienced a burnout.
When brazing lineset connections a nitrogen purge should be used to avoid creating carbon deposits inside the lineset that will be carried through the system and possibly create an obstruction at the metering device.
Before opening the R410A condenser to the rest of the system a deep vacuum (500 microns) must be pulled to thoroughly evacuate and dehydrate the system. This is especially important with R410A systems because the POE oil used with R410A is extremely hydroscopic. (It has a great affinity to water). If a thorough dehydration is not accomplished the POE oil will become contaminated by the moisture left in the system.
Deep Vacuum Process
Proper dehydration (boiling off any moisture in the system so that it can be removed as a vapor by the vacuum pump) only occurs when the pressure in the system is lowered sufficiently (500 microns or less). And the only accurate way to confirm that the vacuum is deep enough is by using a micron gauge. Pulling a vacuum for a certain length of time can not be relied on to determine the level of vacuum achieved. If there is a leak in the system, hoses, or manifold, the pump could run indefinitely without ever reaching a pressure low enough to ensure proper dehydration. Or the vacuum pump itself may be unable to reach the required levels due to poor maintenance practices. Always keep clean oil in your vacuum pump to maximize its efficiency and extend its life.
Steps to complete dehydration:
1. Draw a vacuum until you have a reading of 500 microns.
2. Isolate the system from the vacuum and wait 15 minutes.
3. If the pressure rises to 1500 microns and holds, then there is moisture in the system that has vaporized and needs to be evacuated. Restart the process from step one.
4. If the pressure continues to rise beyond 1500 microns there is a leak in the system. Break the vacuum with nitrogen then locate and repair the leak. Restart the process from step one.
5. When the pressure holds at 500 microns the system has been properly dehydrated.
Once the evacuation is complete, start up and charge the system according to the manufacturer's specifications.
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