Heat Pump Pool Heater
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If a leakage of refrigerant is found which requires brazing, all of the refrigerant
shall be recovered from the system, or isolated (by means of shut off valves) in a
part of the system remote from the leak. Oxygen free nitrogen (OFN) shall then be
purged through the system both before and during the brazing process.
6.6.7 Removal and Evacuation
When breaking into the refrigerant circuit to make repairs – or for any other
purpose –conventional procedures shall be used. However, for flammable
refrigerants it is important that best practice be followed, since flammability is a
consideration. The following procedure shall be adhered to
：
(1) Safely remove refrigerant following local and national regulations;
(2) Evacuate;
(3) Purge the circuit with inert gas (optional for A2L);
(4) Evacuate (optional for A2L);
(5) Continuously flush or purge with inert gas when using flame to open circuit;
(6) Open the circuit.
The refrigerant charge shall be recovered into the correct recovery cylinders if
venting is not allowed by local and national codes. For appliances containing
flammable refrigerants, the system shall be purged purged with oxygen-free
nitrogen to render the appliance safe for flammable refrigerants. This process might
need to be repeated several times. Compressed air or oxygen shall not be used for
purging refrigerant systems.
For appliances containing flammable refrigerants, refrigerants purging shall be
achieved by breaking the vacuum in the system with oxygen-free nitrogen and
continuing to fill until the working pressure is achieved, then venting to atmosphere,
and finally pulling down to a vacuum (optional for A2L). This process shall be
repeated until no refrigerant is within the system (optional for A2L). When the final
oxygen-free nitrogen charge is used, system shall be vented down to atmospheric
pressure to ensure work to take place.
Ensure that the outlet for the vacuum pump is not close to any potential ignition
sources and that ventilation is available.
6.6.8 Charging Procedures
In addition to conventional charging procedures, the following requirements
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