Hydro Pro Heat Pump Type PX21/32 exploded view & spare parts

Hydro Pro Heat Pump Type PX21/32 exploded view & spare parts

This page provides the official exploded-view diagram and full bill of materials for the Bosta Hydro Pro Heat Pump Type PX21/32 (factory reference 7028287). The diagram covers both the PX21 and PX32 output variants within this horizontal inverter series, which uses R32 refrigerant and a variable-speed compressor to deliver efficient pool heating across a wide range of ambient conditions. Use the numbered diagram alongside the parts list below to pinpoint exactly the component you need, whether you are a pool owner carrying out routine maintenance or a technician working through a fault. Most visitors locate their part and have an order placed within a few minutes.

Cómo utilizar el esquema numerado para localizar tu pieza

Every number printed on the exploded-view diagram corresponds directly to a numbered row in the parts list table on this page — locate the area of the unit you are working on, read off the call-out number, then find the matching row to obtain the SKU. Start by identifying the broad zone first: airside components (fan, motor, grilles) sit in a different region of the diagram from refrigerant-circuit parts (compressor, valves, heat exchanger) and electrical-box components (controller, switches, relay). Bear in mind that some reference numbers appear more than once in the diagram where an identical part is used in two locations — always cross-check the written description in the parts list to confirm the component is the one you are looking at. This BOM also contains associated accessories and reference items — for example position 33 groups several accessory parts under a single call-out, so read the full description text carefully rather than relying on the position number alone. Where a position number is shared between a sub-assembly and an individual component (position 25 appears in the BOM for both the junction box body and the right side plate), compare the description and any dimensions given to ensure you select the correct item. If a SKU column shows no value for a position, that part is not currently sold individually; contact our team for guidance. For all positions that do carry a SKU, add the part directly to your basket using the link in the corresponding row.

Main replaceable assemblies on the Hydro Pro Heat Pump Type PX21/32

The airflow assembly is built around the axial fan motor (position 6, SKU 7024943, rated 75 W, model ZWS75-A) which drives a 510 mm × 160 mm fan blade with a 10 mm anti-clockwise bore (position 4, SKU 7024944); both items are common service replacements after prolonged outdoor exposure. The plastic fan net (position 3) and fan protection net (position 8) shield the blade from debris and are structural counterparts to the fan motor bracket (position 10) that holds the motor to the chassis. The top lid (position 12, SKU 7033050, 1115 × 427 mm) closes the upper casing and is supported by two top support plates (positions 11 and 13); the front frame (position 1) and right-side plate (position 25) complete the outer enclosure together with the chassis (position 28). The refrigerant circuit centres on the Mitsubishi SVB220FLGMC-L compressor (position 29) and flows through a 4-way reverse valve (position 23) that enables heat-pump or cooling mode, an electronic expansion valve (position 20), and a filter (position 22). Pool water is heated by the titanium heat exchanger PIV 21/32 (position 27, SKU 7024876), which is the primary reason titanium is specified — it resists chlorinated and salt water corrosion effectively. Refrigerant-side protection is handled by the low pressure switch at 0.3 MPa / 0.15 MPa (position 15, SKU 7011009) and the high pressure switch at 3.2 MPa / 4.4 MPa (position 17, SKU 7011008); a pressure meter calibrated for R32 gas from 0–55 bar at −15 °C (position 24, SKU 7026259) assists technicians during servicing. On the water side, the flow switch (position 18, SKU 7006471) prevents the unit from running without adequate water circulation — one of the most frequently replaced components after a blockage or dry-run event. User control is provided by the glass display CM404 (position 2, SKU 7029494) and the centralised controller 82300052 + 82400021 PIV 21/32 (position 30, SKU 7029489), both of which can develop faults in the event of moisture ingress or a power surge.

Choosing between variants and pack sizes

Position 17 in this BOM carries a single SKU (7011008) for the high pressure switch, but the same diagram row also references two separate temperature sensors with their own part numbers — a 5 K sensor (SKU 7011007) and a 50 K sensor (SKU 7024867). These sensors are not interchangeable: fitting the wrong resistance rating will cause incorrect temperature readings and potential unit shutdown, so confirm which sensor your specific build date requires before ordering. Position 33 bundles several accessories — including the 10-metre extension cable, housing, and rubber feet — into a single diagram call-out rather than assigning individual position numbers; if you need one of these items in isolation, note the individual reference quoted in the description and use our search bar or contact us to locate it. Where dimensions are stated explicitly — such as the 510 mm × 160 mm fan blade (position 4) or the 1115 × 427 mm top lid (position 12) — treat those measurements as mandatory selection criteria, since physically similar parts from adjacent models in the PX range may differ in size and will not fit correctly. If you are unsure whether a part listed without a SKU can be supplied separately, reach out to our team with your factory reference 7028287 and the position number, and we will advise on availability.