Ok guys,I finished up my install today,and as soon as I fired up the compressors they sounded like they were running slow,kind of like they were straining.And it also took 10min-12min to pressurize my tank to 200psi.I have had air suspension in the pass with some lighter duty compressors and they made much more noise and sounded like they were running very fast,these are dual 444c comps.Are my compressors working normal or should I look into something?
How big is your tank? What size is your wiring? What was your battery voltage while they where on?
Also it’s they’re not their.
Tank is 9 gallon,power wire to the comps are 6ga,voltage is a little over 13volts.And If you look at my install pics you will see im running the hornblasters.com relay/pressure switch.And thanks for the language lesson,but when you are referring to “objects” its their,when you are referring to a place its there.I did not know I posted my question on englishlanguageforum.com 
The higher pressure, the harder it is on the pumps, and the slower it will pump as pressure climes. 200 psi is much harder on the compressors compared to around 150 psi. But yes it is normal for the compressors to run slower as they build up.
FYI the specs say 0-200, 10 gallons, 10 minutes 8 seconds.
So THEY’RE (they are) not running super slow. Sorry had to. lol
Maybe they’re more quiet than you’re used to.
Thanks,so maybe THEY’RE working like THEY’RE suppose to,THEY’RE just not as loud as im used to…I would be happy as can be if this dang check valve didnt leak!
Yup mine leaks through the comps too. The check valves suck. Will they do something about it on warranty?
Ah yes, I forgot about your check valve problem. I don’t think that would add to the fill time, but the warranty should cover it/them. Are they both leaking?
I forget who, but somebody on here just bought an industrial check valve to be done with it.
Oh and I really don’t care about the English. I ended 2 sentences in a preposition - LOL
So no offense intended…
This is the ONLY way to go…
Where can I obtain one and how much? Also what is that set screw for? Thanks man!
I got mine at an industrial shop, but this looks to be the same thing. They are rock solid. The screw on the side makes it easy to add anti-freeze in the winter!
i wonder if viar is aware of the problem with these check valves and if they will reimburse the right fix.
Well I got an industrial check valve rated at 300psi and put that in and dam if I dont still have a leak through the same compressor,just my luck…It actually seems to be worse than before I added the check valve.The other compressor does not leak a bit.Only thing I know to do is change the leader hose and hope it has a good check valve in it.As many issues as people have had with the Viair leaking,you would think they would have done something about it!
Old check valve had issues.
People seem to think that we don’t address these things, - we do.
The newest check valves are 3rd Generation and the internal issues that they had in the past have been resolved. The earlier versions had carbon steel springs and thin keeper washers. The latest versions have stainless steel return springs and a 2.5 mm keeper washer.
Still, they aren’t bullet proof. - Keep in mind that whenever you install items with NPT fittings, those fittings are tapered. If you tighten them so much that they bottom out, I can guarantee that the check valve has been damaged from being overtightened which seizes internally.
I don’t get it. I’ve had the same 420Cs on my Tundra now for four years. There’s no leaks and everything works as well today as it did the day I completed the install.
I wish I ran the same luck you did. I know for sure it’s the check valves in mine. I did a leak test on everything couldn’t find a thing so I talked to John he does quiet a few OBA for trucks with air bags and exhaust brakes, he told me to check the compressor intakes and sure enough that’s where they are leaking. Called HB and they said they can send me some new ones but I haven’t yet cause I’m thinking I will have the same issue all over again.
I really wouldn’t mind it if it weren’t for the compressors running each time I turn my ignition. Park my truck tank will have 150 psi come back after 30-45 min and turn my ignition and the comps kick on.
I don’t know about others but I’ve been around pipe threaded fittings for a long time not just for compressors but for water pumps, etc and I can assure I didn’t overtighten it.
Same here,I have been doing airbag and hydraulic suspensions for years and I have never had an issue of anything being over tight,and I have always used Viair comps…This one comp leaked since the install and the other one does not leak,and they are both just as tight.But what bothers me is I just installed a 300psi heavy duty check valve before the inline check valves and I still have air leaking out of the inlet of one.These comps are brand new,but how can I tell if they are the “new” style valves or the “old” style valves? Either way,the 444’s are advertised as 200psi comps,so they should not be leaking.It just seems to me that the valves are weak,because it will leak from 200psi down to about 160psi and it seems to hold at 160psi,but anything over 160psi it wont hold it…