A fridge or freezer is an appliance which removes heat from one area (where the food products are stored) and discharges this unwanted heat to another area (usually into the surrounding air at the back of the appliance).

The “refrigeration circuit” consists of
a freezer section which has very cold refrigerant gas passing through it, a compressor (that’s the big black metal thing near the floor at the back) which drives the refrigerant through the pipes, and a condenser (a series of tubes at the back, which are quite warm to touch. The condenser tubes are actually discharging unwanted heat into the surrounding air.

An air conditioning system is a larger version of the fridge/freezer, which removes heat from one area (a room inside the building) and discharges it through its condenser to outside the building.

In order to make it practical to install an air conditioning system in a building, the “refrigerant circuit of an air conditioner is divided into two parts

A heat pump system, like and air conditioning system, has an indoor unit/interconnecting pipes/outdoor unit, but it also has a reversing valve which pumps the refrigerant the other way around the circuit. This “reverse cycle” operation makes the outdoor unit cool the surrounding air, and the indoor unit discharge its heat into the room. Whilst this may appear very elaborate, there are two very good reasons for having the heat pump option:

1. Most rooms which require cooling, also require heating.

2. A heat pump system capable of providing 7KW of heating in the room, consumes only 2KW of electricity – very cost effective on running costs. This means it is 2/7, or 28% of the running costs of an electric heater.

When the air conditioner is turned on, the thermostat which is fitted to the indoor unit will determine the temperature of the room. If the room is too hot, the compressor will be started, and the “refrigerant circuit” will produce cooling within the room. When the room temperature is at the desired level, the thermostat will be satisfied, and turn off the compressor.

If the system is also a heat pump, it will automatically control the heating process in a similar manner.

Most systems which are manufactured provide heating as well as cooling, because the price difference of a cooling only system is minimal.

The above description of the workings of an air conditioning & heat pump system is very basic.

Descriptions of the types of units, how they are installed, and the types of controls, are explained in the Technical Guide section of this website, under Products. You can print the sales brochures if you wish.

Air conditioning systems are made all over the world. Some are cheap and cheerful, some are very expensive. Mitsubishi manufacture thousands fo systems every week in their Japanese factory, and all are made to the highest standards of quanilty and reliability.

We do not offer free holidays, or televisions, to our installer customers, to induce them to persuade their customers to have our brand, other manufacturers do offer such incentives. We import direct from the Manufacturer, and we supply direct to your installer. This way we keep the prices very competitive.

When you decide to invest in an air conditioning system, choose a recognised brand (hopefully ours) which has a comprehensive technical back up in this country, a techical help desk, stocks of spare parts, really all the things you would check out of you were buying a car. 3 D Air Sales Ltd has been the supplier/distributor of MHI products in the UK and Ireland since 1996. In 2004, 3D was acquired by HRP Ltd, one of the largest and most successful wholesalers of refrigeration and air conditioning products and components in the UK, now with sales exceeding £75m. MHI products, spares, and installation accessories are available nationwide through all 12 HRP Service Centres, each of which have delivery vehicles covering all parts of the UK mainland.

Air Conditioning systems will go wrong if they are not installed correctly. Mitsubishi has the highest standards of manufacturing quality, but if the installer does not do the job properly, it may work for a few months, but then the problems will start.

Make sure the installer can provide references, and and has a good reputation.

1. It is imperative the installer uses ‘refrigeration quality’ copper pipes for connecting the indoor and outdoor units. The pipes must be kept free of moisture, and dirt. The pipes must be properly evacuated, using a vacuum pump, before the service valves in the units are opened.

2. The pipes must be jointed using proper tools, and if they are required to have brazed joints, the joints must be made whist dry nitrogen is purged through the inside of the pipes. This prevents particles of oxides forming, which will cause blockages, and worse, result in acid formation in the compressor oil, ending up with a burn-out.

3. Refrigerant gas is usually required to be added to the system, which is from a pressurised cylinder. The new ozone friendly refrigerants require careful handing, and the additional amount of refrigerant must be calculated accurately, and weighed in to the system using electronic scales.

It is not difficult to get the job done correctly, and it is worth taking care to ensure high installation standards, when making the purchase decision.

If you would like us to recommend an installer, or perhaps two or three who can provide a competitive tender, please contact our Sales Office - see 3D Information & Contacts.