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Precharging Refrigerant
Prerequisites
Before charging refrigerant, ensure that air is exhausted from the gas pipe connecting to the refrigerant cylinder.
Context
- When charging refrigerant, you are advised to use a safety valve to prevent refrigerant leakage during the removal of the leather hose, which may cause frostbite.
- Wear antifreeze gloves when performing refrigerant-related operations.
- Charge refrigerant (R410A) right after checking that the cooling system does not leak and the vacuum level meets the requirements.
Procedure
- Remove the vacuum pump from the vacuumizing equipment, and replace the vacuum pump with a refrigerant cylinder, as shown in Figure 4-3 or Figure 4-4.
- Slightly open the refrigerant cylinder valve and loosen the connection nut of the pressure gauge. Tighten the nut when cold air escapes out of the nut.
- Put the refrigerant cylinder upside down on the electronic
scale. Clear the reading on the balance.
If the R410A refrigerant is provided by Huawei, put the refrigerant steel vessel upside down when charging in the refrigerant. If the refrigerant is not provided by Huawei, check with the refrigerant provider whether the steel vessel has a siphon. If the vessel has a siphon, do not put it upside down when charging refrigerant. If the vessel has no siphon, put it upside down when charging refrigerant. These measures ensure that the refrigerant is charged in the liquid form.
- Open the pressure gauge valves and refrigerant cylinder
valve shown in Figure 4-4 to charge refrigerant.
- Do not move the pipe or steel vessel when charging refrigerant. Otherwise, the value on the electronic scale is influenced.
- When charging refrigerant for a cooling system without a low-temperature component, open only the low-pressure gauge valve. Charge 1 kg of refrigerant from the low pressure side, and then close the low-pressure gauge valve. Then, open the high-pressure gauge valve and charge the remaining refrigerant from the exhaust pipe needle valve.
- When charging refrigerant for a cooling system with a low-temperature component, open only the low-pressure valve of gauge 1 and gauge 2. Charge 1 kg of refrigerant from the low pressure side, and then close the low-pressure valve of gauge 1. Then, open the high-pressure valves of gauge 1 and gauge 2. Charge the remaining refrigerant from the exhaust pipe needle valve and liquid pipe needle valve.
- The amount of refrigerant precharged must be more than half of the total charge amount calculated and less than the total charge amount. If refrigerant is not charged to the total amount in the precharging process, charge the remaining amount of refrigerant during power-on commissioning. For details about commissioning, see Charging the Remaining Refrigerant.
- After refrigerant charging, close pressure gauge valves
and the refrigerant steel vessel valve.
After the injection is completed, tighten the needle valve bonnet, and check whether the needle valve leaks by applying soap bubbles to the valve vent or using a halogen leak detector. If the valve leaks, contact Huawei technical support.
