tmassey
Contributor
It's spring, when a diver's thoughts turn to... compressor maintenance! 
I've got some questions, so I'll start separate threads for each. This one is abut changing the oil. I also have questions about filter cartridges, as well as startup/shutdown procedures.
A bit about my compressor: 6CFM Poseidon PFU-150. It's a 5HP, 3-stage compressor with a block made by Bauer. It doesn't have an oil pressure gauge, so I assume it's splash-lubricated. It's got a single two-part moisture separator, plus a moisture drain in the filter stack on the back of the compressor. It's supposed to have auto drains, but it leaked pressure so I've removed it and simply use three needle valves with tubes to drain the water. Past the compressor I have a fill board with a large single-part gold Bauer separator (which is always bone-dry, of course) and another 32" filter stack, then the back pressure regulator (set to 2000 PSI) and out to my tanks.
Now, oil change: I've never done an oil change on the compressor before. Here's what I did: I ran it for about an hour and shut it down. Then I popped the oil cap off the top (which has the fill level stick), then I put a cut-down detergent bottle below the oil drain outlet at the bottom. I took the bolt off and let it drain.
I was surprised how *slowly* it drained. I kinda expected it to drain like a car: a messy flood. This wasn't like that: it was a trickle. I let it drain and it took maybe 10-15 minutes to finish, and I had a fair amount of fairly dark (but not nearly car engine dark) oil in the bottom. I went ahead and measured it: about 60 oz of oil, and possibly a touch more.
I then put the bolt back in the drain and put 60 oz of oil (Poseidon 751) back in. I used the filler cap/stick to measure: it was within the little notch at the bottom. I was surprised: I thought it would take more. I'm going to leave it for a while and let the oil settle and see if things change.
So, now a couple of questions:
1) How did I do? Is there anything else I should do or not do here?
2) What's the process for turning the compressor back on after the oil change? Anything I should keep in mind?
3) Realistically, how often should I change the oil? The manual says something like, "2000 hours or two years." I put something like 20 hours a *year* on the thing. I also know I'm somewhat hard on the oil: I only run the compressor once or twice a month (though I'm going to use less bank this year to hopefully increase this), and I can't run it at all between November and April because it's too cold and the condensate would freeze. $60 in oil for a change is not the most expensive thing, but it adds up. Is there a better way of measuring oil usability than simply doing it every 2 years?
Thank you very much for your help! I appreciate it.
I've got some questions, so I'll start separate threads for each. This one is abut changing the oil. I also have questions about filter cartridges, as well as startup/shutdown procedures.
A bit about my compressor: 6CFM Poseidon PFU-150. It's a 5HP, 3-stage compressor with a block made by Bauer. It doesn't have an oil pressure gauge, so I assume it's splash-lubricated. It's got a single two-part moisture separator, plus a moisture drain in the filter stack on the back of the compressor. It's supposed to have auto drains, but it leaked pressure so I've removed it and simply use three needle valves with tubes to drain the water. Past the compressor I have a fill board with a large single-part gold Bauer separator (which is always bone-dry, of course) and another 32" filter stack, then the back pressure regulator (set to 2000 PSI) and out to my tanks.
Now, oil change: I've never done an oil change on the compressor before. Here's what I did: I ran it for about an hour and shut it down. Then I popped the oil cap off the top (which has the fill level stick), then I put a cut-down detergent bottle below the oil drain outlet at the bottom. I took the bolt off and let it drain.
I was surprised how *slowly* it drained. I kinda expected it to drain like a car: a messy flood. This wasn't like that: it was a trickle. I let it drain and it took maybe 10-15 minutes to finish, and I had a fair amount of fairly dark (but not nearly car engine dark) oil in the bottom. I went ahead and measured it: about 60 oz of oil, and possibly a touch more.
I then put the bolt back in the drain and put 60 oz of oil (Poseidon 751) back in. I used the filler cap/stick to measure: it was within the little notch at the bottom. I was surprised: I thought it would take more. I'm going to leave it for a while and let the oil settle and see if things change.
So, now a couple of questions:
1) How did I do? Is there anything else I should do or not do here?
2) What's the process for turning the compressor back on after the oil change? Anything I should keep in mind?
3) Realistically, how often should I change the oil? The manual says something like, "2000 hours or two years." I put something like 20 hours a *year* on the thing. I also know I'm somewhat hard on the oil: I only run the compressor once or twice a month (though I'm going to use less bank this year to hopefully increase this), and I can't run it at all between November and April because it's too cold and the condensate would freeze. $60 in oil for a change is not the most expensive thing, but it adds up. Is there a better way of measuring oil usability than simply doing it every 2 years?
Thank you very much for your help! I appreciate it.
