Air source heat pump replacement in Stevenage, Hertfordshire

Making sure that we work with Housing Providers, we are able to visit tenants homes to replace and maintain a variety of renewable and energy efficient technologies.

Air source heat pumps (ASHP) are a renewable heating and cooling system which utilises the transfer of heat from outside to inside a building. They absorb heat from the outside air which is then absorbed at a low temperature into a fluid, which passes through a compressor increasing the temperature transferring this into heating or hot water.

As a domestic heating technology, ASHP are an economic solution to low carbon heating and hot water demand being able to replace any existing heating system.

We were called out from a Housing Provider who reported functionality problems and decreased temperature levels on a tenant property in Stevenage, Hertfordshire.

After the initial inspection of the outdoor unit and indoor cylinder, the cause of the problem was identified and the outdoor unit was replaced.

Rust build-up on the heat pump compressor can severely compromise the structure and threaten the whole operation of the system.

The compressor is a main component of the pump. This component resembles a piston engine in operation. It places the refrigerant in the system under high pressure by compressing it. This raises the temperature of the refrigerant and turns it into a high-pressure gas. The change in pressure moves the gas along to the condensing coil (which may be either the indoor or outdoor coil in a heat pump depending on whether it’s in heating or cooling mode) to start the heat exchange process.

Technical specifications/current status of the system:

  • Mitsubishi Electric PUHZ-W50 packaged

  • Type of Cylinder: Unvented Grant Monowave Heat Pump Cylinder 150L

  • Weather compensation installed

  • Pipe sizes: 15mm 22mm cooper

  • Heat pump on dedicated circuit

  • Heat pump and cylinder are serviced

  • Heating and hot water operating correctly

  • Rusted compressor

ASHP replacement process description:

  • Outdoor unit replaced

  • Lagged pipe work in the cylinder cupboard

  • Flushed the system with heat pump glycol

  • Checked dip switches

  • Bleed all radiators

  • No leaks were identified

  • Flow rate 20l/min

  • Checked all terminals

  • Pressurised both expansion vessels

  • Checked immersion

  • Programmed the LCD controller

  • Showed the tenant how to use the system