this could be also a good start to having the invoice detailings yeah?
Here is a list of what i think may be relevant to include in the sales invoice when you pay:
1. Brand New machines, packaging to be opened in front of customer
2. State quantity and model number of compressor and fan coils clearly.
3 2 installations done with no extra charge
4. Site survey (no extra charge)
5. Vacuum process (state amount of time of vacuum)
6. Unlimited copper piping AND trunking
7. Class 1 PSB rated insulation, 1/2 inch thickness
8. 16mm Drain pipe for all fancoils
9. Grade 23 copper used for all, sizing of pipe according to catalog, bent with proper tools, BCA workers, etc.
10. All labour and transport included
11. No further charges to be incurred by homeowner
I will explain my logic for some of these items
1. Make sure the machines are new and that they open in front of you. I am sure the incidence of companies installing used systems is low but if the company wants to try to install a used unit, at least they know you will be looking out for this and hopefully discourage them. Examine the boxes etc carefully.
7. Most of the time, they will use 3/8 inch insultation. It is quite ok unless your pipes are going to be hidden behind furniture/wardrobe etc. If you use a thinner insulation, the chances of condensation will be higher.
Also, i heard that R410 system pipes tend to be colder than R22 pipes, so it may be better to use thicker insulation.
When i checked with one supplier, they charged extra $50 per fancoil to upgrade to 1/2 inch.
9. As AhNaiz said, R410 systems have higher pressures than R22. So using thicker copper might make sense.
Any comments are welcome!
p/s this is taken from another forum
i would advise you to go there and post to ahnaiz if you have any question he is a better expert than i am