Many people who ask this question, mistakenly interpret it as 2 different HVAC technologies. Actually, those are two different terms for the same type of HVAC technology. Eventually, VRF is the more common term for these types of systems, and this is the term that will be used for the rest of the article. Check out our solutions for HVAC service providers and professionals: Check out our simple solutions.
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Thanks Ryan! The install is the most critical part of a successful system, without a quality install you will not get desirable results. There are many issues that can come arise from install issues, but here are a few of the most common ones.
Leaks and Tightness Test Flares….. I know, everyone hates them but a properly made and installed flare is an effective mechanical joint. Be sure to ream deburr the tubing, use your flare sizing guide tool to assure the flare is a good flare.
The link to the one I use will be at the bottom. Also, be sure to use a torque wrench and torque all flares to the appropriate torque specs. I have come across a lot of them that leak after the change of season with the corresponding expansion and contraction. Be sure to complete the tightness test in accordance with the install procedure, finishing pressure being psi for the FXTQ for 24 hours or more.
Also, In my contracting business, we find that using a good, quality, modern flaring tool with a depth gauge and clutch as well as some assembly lubricant such a refrigerant oil or Nylog can really help make a great, tight-fitting flare with less galling.
Refnets Be sure to mount your refnets within the allowable angle which is 15 degrees for outdoor refnets and 30 degrees for indoor refnets. Finishing Vacuum Be sure to get below microns and hold. A new and tight system should easily be able to get down under and hold there, if not then you want to investigate further. If line sets run through an attic or unconditioned space, this is especially important. Be sure to seal the joints with appropriate glues or tapes designed for the purpose.
See pictures below. Moisture Moisture can be a major issue with the use of PVE oil. This sludge can gum up mechanical components in the refrigeration system which can cause premature failures. Communication wiring Be sure to daisy chain your wiring.
Setting The Units Verify that the units are set in the proper order, the largest unit goes closest to the indoor units on down to the smallest unit VRV 4. VRV 3 has a cross over line that goes between the modules so this is not a concern.
Line Length Measurements Please, please, please keep track of and measure the lineset! Send it to your sales engineer so that the correct additional charge can be calculated. These are critical charge machines so every pound matters.
I have changed many compressors that have nearly no oil left in them. Be mindful of keeping piping on the same level. There are specific rules about oil traps in your install class. Expansion Joints Install expansion joints per your sales engineer requirements. This is important because of the possibility of a large change in temperature that the pipe is under and needs to be allowed to expand and contract. Unit Placement Be sure to have the units mounted on stands above the highest average snowfall.
Having snow pile up or water from defrost freeze in the pans or on the bottom of the coils can be very problematic. Be sure the bottom of the units are clean as that can cause the water not to drain out of the pan also.
Climatisation VRV : une régulation et une gestion des besoins thermiques
VRV or VRF ?