Worcester Bosch · Heat-pump or fixed-AC model
Compress 3400i AWS
Worcester Bosch Compress 3400i AWS is a current single-phase R32 split air-to-water heat-pump family in 4, 6, 8 and 10 kW forms.
Specifications
| Specification | Value |
|---|---|
| Type | air-source, air-to-water split |
| Supply phases | single |
| Rated output (kW) | 4, 6, 8 or 10 capacity name |
| Rated-output conditions | A2/W35 published output is 3.81, 5.98, 7.35 and 7.85 kW respectively |
| SCOP (seasonal coefficient of performance) at 35°C | 4.61, 4.21, 4.34 and 3.95 in capacity order in the MCS directory on 23 July 2026 |
| SCOP at 55°C | 3.15, 2.91, 2.98 and 2.95 in the same order |
| Maximum flow temperature (°C) | 60 |
| Refrigerant | R32 in a split outdoor-to-indoor refrigerant circuit |
| Sound power (dB) | 61 at 4 kW; 59 at 6, 8 and 10 kW |
| MCS certified | MCS HP0329/01–04 current with no end date shown on 23 July 2026 |
| Warranty (years) | minimum 2 under current terms; longer cover is product- and installer-dependent |
Compress 3400i AWS is Worcester Bosch’s current compact split air-to-water range. It has 4, 6, 8 and 10 kW capacity names and uses a refrigerant connection between the outdoor and indoor units.
Split-system identification
The exact outdoor codes are CS3400iAWS 4, 6, 8 and 10 ORE-S. They use a single-phase supply and R32 refrigerant. Because the circuit is split, installation and refrigerant work require the qualifications and procedures stated in the manufacturer instructions.
The 4 kW outdoor unit uses a smaller casing. The 6, 8 and 10 kW variants share the larger published dimensions. The indoor unit is a separate item with its own hydraulic and backup-heater functions.
Output and temperature
At 2°C outdoor air and 35°C water, Worcester Bosch gives 3.81, 5.98, 7.35 and 7.85 kW in capacity order. This illustrates why the headline model name is not the output at every design point. The published maximum heat-pump flow temperature is 60°C.
Sound power is 61 dB(A) for the 4 kW model and 59 dB(A) for the three larger models. The site’s sound-pressure result depends on operating condition, distance and surrounding surfaces.
MCS and guarantee records
The four exact capacities were current in the MCS Product Directory on 23 July 2026 under MCS HP0329/01 to /04, with no end dates shown. Their directory seasonal values differ by capacity and by 35°C or 55°C application, as retained in the structured specification.
Current Worcester Bosch terms provide a minimum two-year heat-pump guarantee and allow longer durations depending on the model and installer accreditation. Correct commissioning, annual servicing and the other terms apply.
Related entries
Manufacturer and reference sources
Brand
Reference type
Heat-pump or fixed-AC model
Last reviewed
23 Jul 2026
Current status
Current in the manufacturer's UK range.