S735C

NIBE S735C is an exhaust-air heat pump with active cooling. Like the standard S735, it combines mechanical extract ventilation, space heating and an integrated domestic hot-water cylinder in one indoor cabinet. The additional cooling function is the material distinction.

NIBE’s UK S735 page says an S735C active-cooling variant is available, and NIBE UK has described S735C installations in its current project material. The detailed European page lists 4 and 7 output classes with several suffixes. The full order code and UK documentation are needed because suffixes can identify configuration and market differences.

Heating and ventilation

S735C extracts warm, stale air from wet rooms, recovers energy and discharges the cooled exhaust air outside. It also needs correctly designed replacement-air paths into the dwelling. Heating performance therefore depends on the building heat loss, ventilation rate and heating-water temperature.

It is not simply an air conditioner added to any existing extract system. Duct layout, airflows, pressure losses, terminals and commissioning all form part of the heat-pump design.

Active cooling

The compressor can provide active cooling through a suitable water-based distribution system. That capability does not establish how much cooling a room will receive. Cooling load, water temperatures, emitter or fan-coil output, flow rate and controls have to be designed.

Condensation is a central boundary. Pipework and components carrying cool water may need vapour-tight insulation, while emitters and controls need to prevent damaging surface condensation. Standard radiators designed for heating are not automatically suitable cooling emitters.

Heating, cooling and ventilation design

The full S735C code identifies the product variant. Sizing then uses its heating and cooling outputs at the selected design conditions, ventilation airflows, hot-water assumptions and electrical load. Cooling distribution, condensate handling, sensors and control logic complete the system arrangement.

NIBE uses R290 refrigerant and S-Series controls with myUplink. Installation and servicing must follow the exact product instructions, including refrigerant-related location and access requirements.

The standard S735 and S735C should not be treated as interchangeable in records. Keep the data plate, ventilation commissioning results, hydraulic settings, cooling design and warranty registration with the handover information.

Related entries

• NIBE
• NIBE S735