People often find they are ‘short of air’ and their minds naturally works towards the compressor – is it too small or is it under performing?
Fortunately, there is a simple test you can carry out yourself to determine the approximate output of your compressor and this may then allow you to look elsewhere for your issues.
Simple load test procedure is as follows:
- Start with the receiver completely empty of air – i.e. 0 pressure on the gauge
- Close the isolating valve to the system
- Turn on the compressor and start your stopwatch
- Note time (T) in seconds taken till the compressor goes off load and what pressure it achieves (P2) in bar.
- Note the size of the receiver (V2) in litres.
Calculation is as follows:
P2 x V2
——— = Compressor output in litres/second
1 litre/second = 2.119 cfm
As a rule of thumb the output of a compressor (at 7 bar) can be related to the HP or KW of its motor.
Screw or Vane compressors – 1HP = 1.89 l/s or 1KW = 2.53 l/s
Piston (or reciprocating compressors) – 1HP = 1.42 l/s or 1KW = 1.89 l/s