Digital Hornblasters Gauge Bad Reading?

I installed my airhorns with the blue digital hornblasters guage. The problem is when the gauge reads around 50 psi my 145 psi pop off valve blows. I called hornblasters and they said be sure to have the sending unit set at 150 (which makes sense). I went in the settings and verified it was set at 150. I even reset it and it still only gets to ~50 psi before releasing. Anyone else had this problem? Thanks in advance.


Everytime I talk to the guys at hornblasters, they tell me to make sure it is set to 400psi. There was a thread about this earlier on… try using the search to find it…

I don’t know what the deal is with the 145 pop off valve that you have, but you are probably running a 150psi system right? You should get a 175psi pop-off

I have a 150 psi safety valve and my dual Viair 400c units cut off at 145 psi. The safety valve never blows, even when the tank gets up to 148 psi on a hot day. My Air Zenith digital gauge is always dead-accurate within +/- 1 psi.

But regardless of your gauge being accurate or not, this should effect when your compressors shut off. If you have the right pressure switch with a 145 psi cutoff or lower then the 150 psi safety valve should not blow. But I did read that most safety valves have a margin of error like +/-10% so maybe your valve is just on the low side, or maybe it has been worn to the point of blowing too soon.

I Agree, it shouldn’t blow because the pressure switch should be 145-off, but the guys at viair or US say that it can stop them as high as 155psi, in which case it will let go at 150 like it should…

Thanks for the replies. I will try setting the sending unit up at 400 psi and see what happens. Hopefully it will read true.

Oh also I don’t have a pressure switch installed. I just use my truck upfitter switch to cutoff the compresser when it gets to ~145. I was mistaken and thought a 150 psi system was max pressure and that I shouldn’t let the pressure exceed that. Which Is why I got a 145 psi pop off valve. :confused:

You should ALWAYS run the compressors with a pressure switch… I use my upfitter switches for the compressors as well, however, I have a pressure switch installed just incase I don’t get to turning them off (I always leave them on anyway) but you should run them with a pressure switch because if you don’t, it’ll void the warranty…

Good to know. Thank you.