Air Tightness Test; Water Discharge Piping Installation - mundoclima MVD DC2 Manual De Instalación Y Usuario

Pipe fittings
Slot the refrigerant piping into the brass nut , and expand the piSlot the

refrigerant piping into the brass nut , and expand the pipe socket. Refer to the
following table for the size of the pipe socket and the appropriate tightening
torque.
External diameter
Tightening torque
(mm)
Φ6.35 14.2-17.2N·m
Φ9.53 32.7-39.9N·m
Φ12.7 49.5-60.3N·m
Φ15.9 61.8-75.4N·m
Caution
• Apply the appropriate tightening torque according to the installation
conditions. Excessive torque will damage the socket cap, and the cap will
not be tight if you apply insufficient torque, leading to leakages.
 Before the socket cap is installed on the pipe socket, apply some
refrigerant oil on the socket (both inside and outside), and then rotate
it three or four times before you tighten the cap. See Figure 4.3.
Apply refrigerant oil
Figure 4.3
Precautions to take when welding the refrigerant pipes
• Before you weld the refrigerant pipes, fill the pipes with nitrogen first to
discharge the air in the pipes. If no nitrogen is filled during welding, a large
amount of oxide film will form inside the piping which may cause the air
conditioning system to malfunction.
• Welding can be carried out on the refrigerant pipes when the nitrogen gas
has been replaced or refilled.
• When the pipe is filled with nitrogen during welding, the nitrogen must be
reduced to 0.02 MPa using the pressure release valve. See Figure 4.4.
Figure 4.4

4.5 Air Tightness Test

Carry out the air tightness test on the system according to the instructions in the
installation manual of the outdoor unit.
Caution
• The Air Tightness Test helps to ensure that the air and liquid cut-off
valves of the outdoor unit are all closed (maintain the factory defaults).
Normal wrench
Torque wrench
Pipe socket cap
Figure 4.1
Flared opening
Flared opening
diameter (A)
8.3-8.7mm
90°±4
A
12-12.4mm
15.4-15.8mm
Figure 4.2
18.6-19mm
1 Copper piping
2 Section being brazed
3 Nitrogen connection
4 Hand valve
5 Pressure-reducing valve
6 Nitrogen
4.6 Heat Insulation Treatment for Gas-Liquid Piping Connections
for the Indoor Unit
The heat insulation treatment is carried out on the piping at the gas and liquid

sides of the indoor unit respectively.
a. The piping on the gas side must use heat insulation material that can
withstand temperatures of 120°C and more.
b. For the piping connections of the indoor unit, use the insulation casing for
copper pipes to carry out the insulation treatment, and close all gaps.
4.7 Vacuum
45°±2
R0.4 ~ 0.8 Create a vacuum in the system according to the instructions in the installation
manual of the outdoor unit.
Caution
•
For the vacuum, make sure that the air and liquid cut-off valves of the
outdoor unit are all closed (maintain the factory status).
4.8 Charge the Nitrogen and Maintain the Pressure
Maintain the system pressure according to the instructions in the installation
manual of the outdoor unit.
4.9 Charge the Refrigerant
Charge the system with refrigerant according to the instructions in the
installation manual of the outdoor unit.

5. Water Discharge Piping Installation

5.1. Water Discharge Piping Installation for Indoor Unit
1. Use PVC pipes for the water discharge pipes (outer diameter: 37~39 mm,
inner diameter: 32 mm). Based on the actual installation circumstance,
users can purchase the appropriate piping length from sales agent or local
after-sales service centre, or purchase directly from the local market.
2. Insert the water discharge pipe into the end of the water suction connecting
pipe of the unit body, and use the ring clamp (accessory 5) to clamp the water
discharge pipes with the insulation casing for the water outlet piping securely.
3. Use accessory 4 to bundle the water discharge piping of the indoor unit
(especially the indoor portion) to the unit body, and the water discharge
piping must be properly covered with insulation casing. Use the tie for the
water discharge piping (accessory 4) to bind them firmly to make sure air
does not enter and condense to form water.
4. In order to prevent the back-flow of water into the interior of the air conditioner
when the operation stops, during installation, make sure the water discharge
pipe slope downwards towards the outside (drainage side) at a slope of more
than 1/100. Make sure that the water discharge pipe does not swell or store
water, otherwise it will make unusual sounds. See Figure 5.1.
5. When connecting the water discharge piping, do not use force to pull the
pipes to prevent the water suction pipe connections from coming loose. At
the same time, set a supporting point at every 0.8~1 m to prevent the water
discharge pipes from bending. See Figure 5.1.
6. When connecting to a long water discharge pipe, the connections must be
covered with the insulation casing to prevent the long pipe from coming loose.
7. When the outlet of the water discharge pipe is higher than the pipe
connection for water suction, try to keep the water discharge pipe as vertical
as possible, and the water outlet connecting fittings will bend so that the
height of the water discharge pipe should be within 1000 mm away from the
base of the drain pan. Otherwise, there will be excessive water flow when
the operation stops. See Figure 5.2.
8. The end of the water discharge pipe must be more than 50 mm above the
ground or from the base of the water discharge slot. Besides, do not put it
in the water.
Caution
•
Make sure all the connections in the piping system are properly sealed to
prevent water leakages.
25
Face upwards
On-site piping
Unit
Attached insulation side
body
heat pump belt
Figure 4.5