Jimbo I understand your concern, and wonder where you think the best spot for mounting them is? What are your thoughts on mounting these compressors in the engine bays, which a lot do, and in fact there are companies making mounting plates specifically for this location. I couldn't think of a worse spot to mount a compressor, as not only are they subject to prolonged heat exposure when not being used, but are drawing all that hot air in when being used also. So hot air is being compressed, and heating up even further.
If you look at the photo below, there is plenty of air to circulate around my compressor when working, and most times this air is only at ambient temperature, or less thanks to the air conditioner running to keep the interior of the vehicle cool. There is also a hug amount of space between the compressor and the seat bottom material, and if anything, the carpet is the closest to the heat of the compressor.
After reading your post, I was confident that heat build up wasn't a problem under the seat, however decided to do some temperature checks on, not only the compressor motor and compressor receiver tank, but also on the seat material under the seat.
I dropped all of my tyre (285.70R17) pressures to 15 psi, and then re-inflated them to 30 psi, taking temperature readings as each tyre was inflated.
Temperature reading were teken with an infra-red temperature gun.
First tyre inflated to 30 psi.
- Inflation time - 1 minute 20 second
- Motor temperature - 24 degrees (c) or 75 degrees (f)
- Tank temperature - 25 degrees (c) or 77 degrees (f)
- Under seat material temperature - 17 degrees (c) or 62 degrees (f)
Second tyre inflated to 30 psi.
- Inflation time - 1 minute 36 second
- Motor temperature - 33 degrees (c) or 91 degrees (f)
- Tank temperature - 33 degrees (c) or 91 degrees (f)
- Under seat material temperature - 20 degrees (c) or 68 degrees (f)
Third tyre inflated to 30 psi.
- Inflation time - 1 minute 40 second
- Motor temperature - 41 degrees (c) or 106 degrees (f)
- Tank temperature - 40 degrees (c) or 104 degrees (f)
- Under seat material temperature - 20 degrees (c) or 68 degrees (f)
Forth tyre inflated to 30 psi.
- Inflation time - 1 minute 50 second
- Motor temperature - 51 degrees (c) or 124 degrees (f)
- Tank temperature - 52 degrees (c) or 126 degrees (f)
- Under seat material temperature - 23 degrees (c) or 73 degrees (f)
At the end of the test I also took temperature readings from the seat frame, and from the carpet around the compressor, and the highest reading I got was 35 degrees (c) or 95 degrees (f).
After this test I am confident that there is absolutely no chance of any of the material around the compressor being damaged due to heat, nor is there any chance of the under seat material catching on fire.
Thank you for raising the issue though, as if you hadn't I wouldn't have done this test and known for sure.