For the last 4 years I've owned a Coltri MCH-6/SH Compressor, which I've been using to fill my air gun air tanks. The compressor only has 7.5 hours on it and until today it has always fill my tanks without any problems to 4700 PSI, at which point the safety valve opens and wont allow any greater pressure. Today was the first time I've used the compressor in a bout 2 years as I haven't shot an air gun in about 2 years. The Honda engine fired right up and ran fine until my tank got to about 4,000 PSI, at which point the engine bogged down and then stopped. And a bit of air began exiting the compressor's air filter intake until I shut off the tank valve and opened the air bleed valves on the compressor. The engine started right up again when I pulled the ripcord but once again when it got to about 4,000 PSI the engine bogged and then stopped. I think it might be a bad check valve somewhere on the compressor which is allowing high pressure air to flow back into one of the low pressure and much bigger cylinders. Anyone have any thoughts on what might be the problem?
Problem with my Coltri Compressor today
- Thread starter azccj
- Start date
Give Nuvair a ring at 1-(805)-815-4044. Their techs have always treated me right - good guys!
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4 years are probably out of warranty, but 7 - 8 hours in that time, thats not much i would say, and should warrant some good service.
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A 4700psi “safety valve” should not really be used as a cutoff for every fill. 4700psi is too high to regularly run the compressor. You should shut down the fill when you reach the tank limit (usually 300bar or 4500psi). If you do not want to monitor the fills, than you should install the autoshutoff.
But it sounds like you could be right about the check valve or the gas engine might also be weak.
But it sounds like you could be right about the check valve or the gas engine might also be weak.
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Hmmmm Coltri supplies a 330bar~4785psi safety valve, and they clearly states that when the compressor is started to run it with closed bottle to ensure the valve works as intended. If they deem it fit for such a valve i see no problem running the compressor to 4700psi.
https://coltri.com/en/product/final-safety-valve-330-bar/
https://coltri.com/en/landing/icon-petrol/
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Did you ride it hot and just put it in the stable?
Horses die from that and so does compressors.
A lot of moisture will accumulate in the engine oil and if no oil was sprayed into the intake then return valves will corrode. There will always be moisture present in the system. Run it for a couple of minutes with no load and for the final 10 seconds spray some good oil into the intake (Alphabet org comes to mind!). That way you have preserved all internals. Detatch the airfilter before adding oil ;-) DONT use WD-40, it's a joke as a lubricant and will dry to a varnish like state given time.
Alphabet org is an extremely good lubricant and it has lots of additives that deal with water in a good way.
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2 years without running it is a long time. That's like leaving a car sit for 2 years....I would suggest running it once a month regardless of if you need it or not. Hope you get it sorted out. Let us know the outcome.
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For safety valve testing, Coltri recommends doing it after every 50 hours of use. Doing it on every fill seems excessive.
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I think I found my problem. Today I took the 4th stage cylinder head off. It was really gunky in there but that wasn't the problem. The problem is a cracked valve plate in the 4th stage cylinder head. I called Nuvair today and ordered a new one along with a a spare and a couple of copper sealing washers. Hopefully it will be here in a few days. After I install the new valve plate I'll give an update. For anyone else who might need to work on one of these I'll give a bit of advice. The entire compressor and everything that is attached to it can be lifted off the frame as one piece. If you follow Coltri's instructional videos they have you disassemble everything attached to the compressor before removing the compressor from the frame. Which is a lot more work than removing the whole unit to work on just one cylinder.
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When the air tank cools the PSI lowers from 4700 to 4500 PSI. I'm guessing that's why they have the safety valve set at that PSI.
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I guess that's a way to do it. I chose my safety valve to be a little above the fill pressure of the tank so that is will not blow before the compressor shuts off (automatically) or in my case (no auto shutoff) before I shut it down manually.
My safety valve is 330bar. I fill tanks rated at 300psi, 300bar, and 4500psi. I always shut the compressor down at the tank rating, not after the safety valve blows. I consider the safety valve as a last resort safety feature.
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I received my parts yesterday within 24 hrs of placing my order with Nuvair. So today I replaced the 4th stage valve plate and cleaned the valve seat/cylinder top, on my lathe. All back together and working properly now.
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