I really like symbol used. It has some depth to it. I am not too sure about using orange for a color but how you incorporated it into the symbol makes the design more interesting.
Can you bring forward the idea of a control panel (Like the dash board of an airplane)? This would be the types of "INSTRUMENTS" we as a company would fix.
95 and 94 needle pointers look good. Try using 84 and 85 gauge colors: Needle pointer in the green for good, over pressure or over flow will be red, organge will be low flow or low pressure. Thanks.
Make 144 have a metalic shiny silver (Like a table spoon) on that outer grey ridge and that will look so close to the real thing I see in the industry. THANKS!
Good with 155. We now need to look at the gauge readout. Whent the dial is pointing to red it means "OUT OF CONTROL" or "PROBLEM" or "DANGEROUS". If we could change the scale to have the pointer on green for "CONDITIONS ARE GOOD" then to the right have the RED and to the left have the ORANGE. Thank you.