Airtech Pty Ltd
attn. Barry Machin
971 South Road
Melrose Park SA 5039

17 April 1998

Dear Barry,

The installation of the air conditioning system has now been completed. Unfortunately, we have discovered a number of problems, some of them serious.

As you will be aware, we have retained the sum of $200 from the invoice pending repairs to the plasterwork caused while installing the control unit and switches. In view of the surprising extent of the damage caused, I do not believe that your people will be able to perform the repair to our satisfaction. This repair requires some paint work, and I suspect it will be difficult to match the colour of the wall. I had therefore intended to call in a specialist in this area. If you wish, of course, we will let your people do it, but this could prove to be a waste of time for all concerned.

We have also had some problems with the unit itself: the circuit breaker has tripped twice. I attribute this to incorrect dimensioning. Although the compressor is rated at 23.8 A, your electrician installed a 20 A circuit breaker, although I drew his attention to this problem before he started. Please correct this problem as quickly as possible. I am going overseas for two weeks starting on Sunday, 19th April, and my wife is concerned that she will have difficulty if the unit malfunctions again.

In addition, Jeff, the electrician, told me just before leaving that it was not permissible to turn the dampers on while the unit was running, since they could burn out. If I were to do so, the guarantee would be invalidated.

I find this unacceptable for two reasons: firstly, there should be no reason to build or furnish dampers like this. Secondly, any such information should be supplied in writing. I am not sure whether this information is correct. Please confirm or deny it. If there are any other unwritten things I should know about the unit, please let me know in writing.

These are relatively small matters. What concerns me much more are the following:

• You have installed a total of seven zones, six of them controlled by ``dampers'', which I had assumed would control the air flow and thus allow a temperature regulation. In fact, I discover that they are binary devices: they are either on or off. I can't see any use for this kind of device. If I turn any zone off for any length of time, the temperature will wander from the temperature of the active zones. When I turn it on again, there is no way to return the temperature to that of the active zones, since it will only be heated at a rate proportional to that of the active zones. In addition, there is no feedback about the actual temperature in the rooms, which can be influenced by such factors as wind and sunlight. This effectively makes the zones useless for temperature control. I had expected as a minimum that each zone would contain its own temperature sensor and an independent means of adjusting air flow so that it could be heated of cooled independently of the others.
• The rate of heating is very difficult to adjust. In some cases, it appears impossible: although the vents are fully open, we have not been able to adjust the temperature in the master bathroom to the same temperature as the rest of the house. There appears to be inadequate air flow. In the kitchen, on the other hand, we have not been able to keep the temperature low enough.
• The control unit is primitive, and the description is inadequate. I have had to discover the function by trial and error. In particular, I had expected to leave the slide switch cool/auto/heat in the position ``auto'', but this appears to create alternate heating and cooling\(emnot a useful function. On the other hand, it appears that I must leave the fan in the ``auto'' position, in which it will not blow less than ``medium''. If I select ``low'' fan, it continues heating after the set temperature has been reached. This is inadequate. The timer appears to be useless, since it does not provide for different temperatures at different times of the day or night.

Sincerely,

Greg Lehey