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A Typical Heat Pump Repair Case: Resolving Severe Outdoor Unit Frosting of RJP-150F/SN8 Heat Pump
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03/16/2026 We sincerely appreciate our customer for sharing this valuable repair case of the RJP-150F/SN8 R32 15 kW heat pump, which effectively addresses the issue of severe outdoor unit frosting and unsuccessful room temperature rise.
The customer encountered a challenging situation: a new family house with a 260 m² floor heating area was being heated for the first time. Despite the outdoor temperature being around 0°C, the room temperature failed to increase even after 24 hours of operation. The heat pump performed satisfactorily in heating domestic hot water (DHW) but struggled with floor heating— the floor temperature remained stuck at 20°C for 20 hours. Prior to seeking further solutions, the customer conducted thorough checks: confirming no refrigerant leakage, refilling the refrigerant to the required amount (1900g + 240g for 12m pipes at 20g/m + 36g for 12m pipes at 3g/m) with a total copper pipe length of 17m, verifying the normal operation of the 3-way valve, and observing that the compressor frequency could reach 70Hz at startup.
solely on initial assumptions.
This case draws a crucial conclusion: the heat pump itself was functioning properly. The insufficient water flow likely caused high refrigerant pressure in the system during defrosting, preventing the completion of the defrosting cycle and leading to severe frosting on the outdoor unit. It emphasizes the importance of diagnosing problems based on actual conditions rather than relying solely on initial assumptions.
Additionally, long-term monitoring of the heat pump’s operation via WIFI would help identify such hidden issues more efficiently, providing data support for accurate troubleshooting. This shared experience offers valuable insights for handling similar heating system challenges in the future.
