Full Piping Services

Piping for Variable Refrigerant Volume (VRV) and Variable Refrigerant Flow (VRF) air conditioning systems is complex. Too complex to handle without the proper training, experience, equipment, and tools. Instead of doing all the work yourself, or hiring a contractor who has done only one project like yours before and doesn't really know how it works, let Lightning Mechanical help. We're highly experienced in piping for VRV/VRF systems with many years of service in New York, New Jersey, Northern Maryland all the way to Southern Maine, and Harrisburg, PA. We can also reach you in Boston and Albany through our subsidiary: Lightning Service Group.


Our customers range from small facilities like doctor's offices to large facilities like universities, hospitals, and data centers. We typically work on both new construction projects and renovations or retrofits. Our customers are residential homeowners who want their cooling systems to be efficient and environmentally friendly; to save them money on monthly energy costs. We help our commercial customers by providing them with quality workmanship and prompt service so they can get back to business.

We are also available as subcontractors for other HVAC contractors who might need an expert partner to repair and install VRF refrigeration piping.

Call us today at (973) 763-0300 or Email us at Craig@lightningmechanical.com

How Lightning Mechanical does Refrigerant Piping Work

Refrigeration piping is process piping. Process piping is the industrial process of transporting matter in different states (in this case, gas, and liquid). A process piping service needs to account for pressure differences, temperature differences, expansion, and fire protection. Our experience with such systems means that we won't get blindsided by engineering problems like wall thickness and flange ratings that lead other companies to take shortcuts. Instead, we find innovative solutions tailored to your structure and in line with industry standards. Our professionalism, superior workmanship, attention to detail, and dedication to our customers have made us the go-to choice for process piping services across the New York City tri-state area.

Our Process Pipping Methodology

VRV systems will have a low-pressure line, a power exhaust line, two gas lines (one for cooling and one for heating), an electric box with contactor and shunt trip, an indoor fan coil unit or outdoor unit with a compressor, a high-pressure line, and one or more remote units.

Here's a brief overview of the standard refrigerant piping service methodology for full single-zone VRV/VRF systems; scroll down to view in detail the complete services that we offer to assist you with your VRV/VRF piping projects.

Piping Configuration
Ozone depletion potential (ODP) values should be considered when determining the refrigerant that is used in VRV/VRF systems. The ODP value for R-407C (1, 1, 2-trichloroethane) is 0.055, while R-410A (1, 1, 1, 2-tetrafluoroethane) has an ODP value of 0.020. We run calculations to determine exactly what will work best for your refrigeration piping. This helps you stay clear of EPA penalties and reduce energy bills.
Charging Method
There are two options available for the method of charging. The first option is to charge using sight glasses on each valve; the second option is to use a fixed metering device (FMU) followed by service ports. If FMUs are used, they must be remotely located from the indoor unit or outdoor unit.
Ozone Depletion Regulations Compliance
Ozone depletion potential (ODP) values should be considered when determining the refrigerant that is used in VRV/VRF systems. The ODP value for R-407C (1, 1, 2-trichloroethane) is 0.055, while R-410A (1, 1, 1, 2-tetrafluoroethane) has an ODP value of 0.020. We run calculations to determine exactly what will work best for your refrigeration piping. This helps you stay clear of EPA penalties and reduce energy bills.
Piping Length
The refrigerant charge in VRV/VRF systems is low, and therefore these systems will not maintain pressure in a long straight run of piping. This means that all vent lines must be kept as short and direct as possible, and they should never exceed 90 feet in length. If they exceed 90 feet, an accumulator should be installed before the vent line.

Indoor Unit Piping

Self-contained indoor units (fan coils) are preferred over other indoor units because their internal piping requirements are more straightforward than different indoor unit designs. When using other types of indoor units, there may be additional piping requirements to install.

The evaporators in the indoor units should be kept below any heating coils so that warm air will not contaminate them, resulting in poor cooling performance. When arranging piping, keep it close to the wall on one side, and far away from radiators or other devices that produce heat. This is because if copper tubing containing refrigerant is located close to a heat source, it will expand and rupture.

Mini-Split Piping

Mini-split VRF systems are becoming more popular in North America due to their large energy savings over conventional air conditioning systems. One of the reasons these systems are so efficient is that they use a variable volume (high and low side) refrigerant system instead of a fixed volume one like conventional systems.

The compressor and outdoor fan (indoor units only) must be equipped with limit switches or pressure switches to stop operation if refrigerant pressures fall below preset values. These switches must be accessible and can be reset by hand (limit switches) or automatically (pressure switches).


The high- and low-pressure sides of the system must either be connected, or there should be a service valve installed between them. If they are connected, then an equalizer line is required to distribute refrigerant properly in case one of the pressures deviates from the other. If a service valve is installed, make sure that it can be removed without disturbing any of the piping or electrical connections.

Piping Accessories

When using copper tubing, bend reliefs should be used to prevent kinking and possible system damage due to reduced flow. When using aluminum tubing, expansion fittings must be used in order to avoid buckling due to expansion.

Outdoor unit piping must be secured, and it should never be allowed to come in contact with any other part of the system. If there are loose fittings on an outdoor unit, tighten them before starting the system. We ensure that tubing clamps or supports are installed every 18 inches.

Water Traps

Water traps must be installed at the low-pressure side of the evaporator and any other point where air can enter the system. The water trap must be located as close as possible to the evaporator so that only dry; warm air comes in contact with it. We make sure that all water traps are removable for easy cleaning.

VRV Design

Using our extensive knowledge and experience, we can help you ensure that your VRV/VRF system operates at peak performance. We have a wide variety of both small and large equipment for rent, which enables us to provide the following piping services:

  • Accumulator charging and testing
  • Frost-free piping systems installation and conversion
  • Indoor Unit piping and charging
  • Outdoor unit piping and charging
  • Liquid line (evaporator) and suction line (compressor) piping and charging
  • Suction service valves installation and repair
  • Suction line leak detection using refrigerant dye
  • Outdoor unit installation and removal
  • Core drilling (for new construction or retrofitting)
  • High-temperature hot water to refrigerant conversion
  • Liquid sub-cooling installation
  • Superheat installation or removal
  • Compressor oil to refrigerant conversion
  • Hermetic compressor replacement
  • Compressor overhaul and seal replacement
  • Compressor retrofit with new hermetic or semi-hermetic compressors
  • Manifold gauge set rental, purchase, and calibration services
  • Copper and aluminum tubing bending, flaring, threading, and cutting

We can also provide accurate charge calculations for your VRV/VRF system. We have the necessary equipment to accurately measure the amount of refrigerant in your piping system.

It's a full piping service for a reason; there isn't much we don't do. Please write to us here to let us know the specifics of your manufacturing process or refrigerant gas pipe requirements.

VRF Refrigerant Piping Design

VRF piping design can be confusing, with most manufacturers publishing different piping configurations. We provide consulting services to ensure that the system is designed for proper flow and efficiency. Our team of experts has installed hundreds of VRV/VRF systems in industrial, commercial, and residential settings, enabling us to optimize your VRF system's performance by providing a custom design tailored to your building.

Process Piping services we don't provide

Need something done on your VRV/VRF piping systems that you can't find on our service list? Call us and ask us about it. We offer specialized piping systems for low-temperature applications across a full range of industries.

We've worked with clients that required carbon steel piping, extra fire protection, unique materials fabrication, and specific refrigeration gases.


Contact Us

65 Newark Way, Maplewood, NJ 07040, US
Monday - Friday: 8am - 6pm
24 Hour on call emergency service available