VRF/VRF Piping Design VRF

VRF piping design is another crucial task in VRF installation to increase system efficiency and reduce installation costs.

All piping capabilities are different; if you adopt a flexible VRF piping design where you can use more Y-shape joints and headers, the total piping length will be shorter.

It takes less refrigerant and minimizes total cost. But what is the process of designing a VRF piping diagram, and where to start?

Step 1 — Develop a Preliminary System VRF Piping Layout 

The VRF piping design process starts with a comprehensive system layout design, including VRF refrigerant piping, indoor fan coil units, circuit controllers, and condensing units, considering your project’s performance requirements.

This design will help you place branch selectors in the most accessible locations, requiring fewer indoor fan coil units, less piping length, and less refrigerant charge.

Step 2 — Get Your VRF Piping and Wiring Diagrams 

Based on the primary VRF piping layout, your VRF manufacturer representative will provide you with a software calculation of:

  1. VRF Piping Diagram
  2. VRF Electrical and Control Wiring Diagram
  3. Initial Equipment Selection Options
  4. Total Amount of Refrigerant
  5. Total Pipe Sizing and Length
  6. Model Numbers of Accessories and Equipment

The schematic electrical and control wiring diagrams from your VRF manufacturer will present how all the system components are powered and controlled, including power and control wiring size and type.

If the VRF piping diagram exceeds the allowable length, the software will indicate it, and you can quickly recalculate the system parameters and update them in the software.

For manual calculation, you can also use the VRF installation manuals and refrigerant pipe sizing charts provided by your manufacturer.

Step 3 — Verify VRF Piping Rules Compliance with ASHRAE Standards

When your VRF piping design is ready, verify that the VRF piping layout complies with ASHRAE VRF piping rules, standards 15 and 34.

This includes:

  1. Checking if the room’s occupancy classification aligns with ASHRAE Classification Standard 15.
  2. Calculating the minimum allowed floor area based on the total system refrigerant charge and ceiling height.
  3. Ensuring the minimum permitted floor area is not smaller than the room with parts installed by the refrigerant system.
  4. Ensuring adequate room volumes.

Additionally, meet other ASHRAE VRF refrigerant piping installation requirements, such as:

  1. If the piping has proper support.
  2. If the pipe is isolated from other pipes.
  3. VRF piping is not installed in enclosed stairways or moving object shafts

The following steps will ensure an efficient, cost-effective VRF piping layout and installation.

VRF Piping Installation

VRF Piping Installation

Having a good VRF system is only half the battle, the other half is getting it right.

Therefore, you need to understand VRF System Installation and VRF Piping Installation.

The most important steps in VRF pipe installation are cutting the appropriate length of copper pipe, insulation, and ensuring the correct connection of the copper Y joint.

Remember to ensure that both ends of the copper pipe are sealed at all times to prevent dust from entering the interior.

While cutting the pipe(use a pipe cutter), make sure the length is accurate, and remove copper burrs with a Deburring Tool.

Check the liquid and gas piping dimensions before connecting the refrigerant pipe.

Make sure one refrigerant pipe does not touch other refrigerant pipes, unit panels, or base plates.

When connecting the twinning kit to the outdoor unit, the length of the straight pipe must be 500 millimeters or longer.

VRF Piping Insulation

VRF Piping Insulation

After cutting the pipes properly, provide sufficient insulation work into liquid and gas pipes to avoid dewdrops(Learn VRF pipe insulation).

Remember, the inner diameter of the insulating materials you’ll use should match the size of the refrigerant pipes. Ensure there is no gap with the indoor unit pipe insulator.

This is because if there is air between the insulation and the copper tubing, condensation will form which will corrode the VRF lines.

In brief, it has many benefits like preventing energy loss, maintaining unit performance, and saving you from high temperatures.

Related product: Insulated Copper Pipe

VRF Y Joint Installation

VRF Y Joint Installation

From a cost perspective, VRF Piping installation accounts for 1/3 of the entire system. (learn VRF system cost)

Therefore it is also important to study the installation of VRF lines.

There are two types of refrigerant pipe connection methods for indoor units. It’s Brazing and Press.

In the brazing method, we don’t recommend using an anti-oxidizing agent as it may cause VRF Y joint corrosion and degradation. (Learn copper Y joint)

Using other brazes, like non-oxidation brazes with nitrogen purges, doesn’t have this downside.

But it also produces excessive heat, which may cause the VRF pipe to burn and shrink by heat.

So far, there is no suitable soldering method to solve the defects of VRF pipe soldering.

So, Miracle recommends you use braze-free connection technology.

HVAC press tools and fittings are the best solutions for VRV/VRF Air Conditioner systems.

Miracle braze-free HVAC tools and fittings can used for copper, aluminum, stainless steel pipe, etc.

Whether it’s a Copper Y joint or an elbow, you can use a Miracle ring.

Contact us to get the right VRF pipe installation solutions.

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