swimjim
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Re: RIX SA3E

Tue Jun 06, 2017 6:01 pm

Looks like your drive belt may be a little loose Eben. Might want to check that out.

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SurfLung
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Re: RIX SA3E

Thu Jun 08, 2017 1:48 pm

Hi Jim,
Yeah, that flappy look has bothered me, too. I've thought of putting an idler wheel in there. The belt is actually very tight (I think)... I have a 3 foot pry-bar I lean on as I tighten the motor mounts. The top is the slack side when the compressor is running so maybe that's why it looks like that.
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antique diver
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Re: RIX SA3E

Thu Jun 08, 2017 2:28 pm

SurfLung wrote:Hi Jim,
Yeah, that flappy look has bothered me, too. I've thought of putting an idler wheel in there. The belt is actually very tight (I think)... I have a 3 foot pry-bar I lean on as I tighten the motor mounts. The top is the slack side when the compressor is running so maybe that's why it looks like that.


There is a page on correct belt tensioning in the manual for my SA6. Probably included in your SA3 manual as well, but if not I can scan it to you, although the specs could be different on the smaller block. Too tight is not good for your shaft bearings on motor and compressor
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Re: RIX SA3E

Wed Jun 21, 2017 12:18 pm

Filled at 3 cf/min last night...
- Well, after all of the piston re-ringing and head rebuilding, I slipped the adjustable speed pulley onto the RIX. The specs say at 2300 RPM, it will pump 3 cf per minute fill rate. I turned it on and measure the compressor's RPM... It was a little too fast at 2400+ rpm. So, I dialed the adjustable pulley back one turn, re-tightened the belt and turned it on again. I think it measures 2296 rpm... As close to 2300 as I can get!
- I didn't fill tanks right away so last night when filling and topping off tanks for the Fortune Pond trip was the first time I could give everything a good try. Good results all around:
1 - The fill rate was noticeably faster. My twin tanks and Aluminum 80s actually got warm during their fills... Usually only the single 38s and smaller get warm when I fill them.
2 - The compressor was running cooler. Usually the fan air coming out the back is very warm. This time is was just slightly warm.
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SurfLung
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Re: RIX SA3E

Fri Aug 04, 2017 1:23 pm

- I'm wondering if my Back Pressure Valve (aka PMV) is working properly. When I don't have the hose connected to the filter array and turn on the compressor, there is airflow coming out. I thought it was supposed to have no air coming out until 1800 psi. BUT, when the hose is connected to the filter array, it does seem that the back pressure valve holds back until 1800 because that's when the needle starts to move on the filter array's gauge.
- However, I disconnected the hose at the BPV and there was some water in the hose. The filter array is located a couple of feet above the BPV so the water stays mostly at the bottom. But I'm wondering if there should be any water in there at all?
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Re: RIX SA3E

Fri Aug 04, 2017 6:38 pm

SurfLung wrote:- I'm wondering if my Back Pressure Valve (aka PMV) is working properly. When I don't have the hose connected to the filter array and turn on the compressor, there is airflow coming out. I thought it was supposed to have no air coming out until 1800 psi. BUT, when the hose is connected to the filter array, it does seem that the back pressure valve holds back until 1800 because that's when the needle starts to move on the filter array's gauge.
- However, I disconnected the hose at the BPV and there was some water in the hose. The filter array is located a couple of feet above the BPV so the water stays mostly at the bottom. But I'm wondering if there should be any water in there at all?
Here's the manufacturers info and schematic on the valve that you have mounted after your final separator on the compressor. http://valvesandregulators.aquaenvironm ... 20906R.pdf
They are pretty simple, and with your abilities you will have no trouble opening it up and checking out the internals.

They do let a small amount of air seep past the hard seat and ball, and with normal wear can get worse, but I am not sure what is going on with yours since it seems to be responding normally according to your gauges.

About the water... the small original 3rd stage separator will allow some moisture to get past it in normal use, and it ends up in the downstream PMV and air lines. That's why I wanted the secondary separator as the first component in your remote filter array. That separator should catch a lot more moisture before it can reach your filter media, greatly increasing the media life.
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Re: RIX SA3E

Wed Aug 30, 2017 10:21 am

My RIX Purrrs...
- I have had a low level but persistent rattle ever since I got the RIX. Sometimes pressing on the cowl would change it and sometimes not. I eventually concluded it was something in the swash plate, turnbuckles, or bearing system... And I thought it would eventually reveal itself in some sort of breakage.
- Until this Summer, I never ran it without the cowl because the cowl plays a significant role in the cooling fan system. But this spring I was running on a cool day and decided to try running it without the cowl. Eureka! There was no rattle. I ran it up to high pressure and no rattle. I ran it long enough to warm up and fill a tank... Still no rattle. So, the rattle had something to do with the cowl.
- I inspected the heck out of the cowl and finally found a depression where it was pressing against one of the low pressure air tube loops... It actually had pressed an indentation into it with the heat that these tubes build up... And the inconsistent noise was probably due to the expansion and shrinkage of the tube with the temperature change.
- So I got out my jig saw and cut that section out of the cowl. RE-installed it and now there is no more rattle! Holy Cow... This thing almost PURRS.
- Last night I filled all my Twin 38s after diving them at Fortune Pond last weekend. The RIX filled them fast enough to generate some heat and quiet enough that I forgot to put on my ear muffs several times as I walked in and out of the garage. Awesome compressor. :)
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couv
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Re: RIX SA3E

Fri Sep 01, 2017 5:51 pm

SurfLung wrote:My RIX Purrrs...... So I got out my jig saw and cut that section out of the cowl. ....
Don't tell me, "Fits like a glove!"

Well done.

Some older airplanes I worked on had chafing pads on hydraulic or pneumatic lines that rubbed where they shouldn't. The pads were made of leather-but I would bet a thin strip of teflon would work mo-betta.
A sincere THANK YOU to all at VDH who make this wonderful resource available and to all the thoughtful contributors.

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Re: RIX SA3E

Sun Oct 01, 2017 11:06 pm

Hey everyone... New to this site, but Ive seen the posts about the different RIX units you guys have and thought perhaps it would be beneficial for us all to be contacts.

I have a RIX SA-3E that I acquired and have redone from the ground up for my scuba training business. It has been a great machine for the most part, but has had a few issues from tubes leaking, piston rings failing, and head issues (most recent).

I have become best buds with Chirsta A. at RIX and feel I've become quite knowledgeable in these machines for self teaching most of it. I have enjoyed reading everything you all have shared.

I apologize if I'm stepping on a thread, just thought id introduce myself. Bryan from Texas
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SurfLung
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Re: RIX SA3E

Mon Oct 02, 2017 11:55 am

- Hey Badlander! VERY nice looking RIX! Thanks for sharing the pictures. Yes, I hear you about the rings and head issues. But man, they certainly are fixable at a reasonable price... Thank you Christa/RIX!
- I hadn't thought about getting new decals...
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Re: RIX SA3E

Mon Feb 12, 2018 6:43 pm

Check for Loose Zerks!
- I was servicing my RIX last weekend and noticed one of the grease zerks was loose. I checked the other two and they were wobbly, too. The zerks fit a tiny 1/4" box wrench and I was able to tighten them back up easy enough. But I don't think it did them any good to be wobbling when that thing is running. And, not having them sealed tight was probably not good for the grease capacity... Hopefully it didn't result in any more wear than usual on the turn buckle bearings.
- Needless to say, it would have been a bad thing if one of those zerks fell off into the mechanisms while the RIX was running. :!:
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Re: RIX SA3E

Mon Feb 12, 2018 8:09 pm

Thanks for the service tip! I had not thought about checking those between lube intervals.
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Re: RIX SA3E

Mon Jan 07, 2019 10:42 am

Update RIX-SA3E...
- I can't believe it has been 5 years since I hydrotested three of my sets of Twin 38s and Twin 42s... But it has and I've disassembled them and taken the opportunity to look inside to find they are all in Pristine (no Rust) condition on the inside. Twin tank sets are such a hassle to take apart, and since these are STEEL and not the dreaded aluminum, I have dispensed with annual visual inspections. They have been duly hydrotested, of course. AND, I have looked inside my steel 72s and steel 50s to see if the compressor was pumping any moisture (and it never has).
- But it's good to confirm and I'm really pleased that these steel Twin 38s and 42s will get past the 5 year testing easily.
- Before I got the RIX, I was filling these tanks cascade style from 3000 psi aluminum 80s. I sure learned alot in the past 5 years.
- Thanks to all of my VDH friends! :)

BTW - I have to get these Twin tanks tested, re-assembled and trial dived in time for Sea Hunt Forever which is only a few weeks away... March 2-3. Come and see us if you can... It's at Silver Springs Florida.
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Vintage Diving Technique are Why I Got Back Into Diving.

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Re: RIX SA3E

Tue Feb 12, 2019 11:15 am

Slow Fill Rate Solution...
- I started seeing a slower and slower fill rate with my RIX, starting last Fall I figured it was down to 2.2 cfm. And then this winter down to 1.8 cfm... This is down from a high of 2.7 cfm last winter. This is filling tanks in my cool and very dry basement (humidity less than 30%). After checking for leaks, belt slipping, clogged intake, etc. I could find no cause. So, I serviced the cylinder heads with cleaning and new O-rings. No change. Finally I had nothing left but to check the piston rings. Bottom line is that they were gummed up and stuck in a compressed state, not sealing very well at all. AND, the 3rd stage piston was actually broken into two parts.
- As usual, I ended up learning a heck of a lot from solving and repairing the problem. After servicing the rings, I did a fill rate test and set a new personal record of 2.875 cfm. I wrote it all up to post under the "Fill Rate Challenge" section of this forum. But I think its significant enough that I should also include it here under my general RIX SA3E thread:

RIX Compressors Are Different...
- I worked on the compressor Saturday and got the new piston installed and everything back up and running smoothly... Perfectly, actually. I learned a lot on this most recent challenge of solving the slow fill rate. And, I've been meaning to write it all down so I don't forget. To start with, probably the most valuable lesson here is that RIX Compressors Are Different. Certainly they share aspects of Air Compression with other compressors. But the "Oil-Less" compression mechanism has some unique aspects that I don't think the instruction manual completely explains.
- Teflon Rings: There's no crank case filled with oil. The compression rings on a RIX are made of a teflon material that's flat and coils like a typical piston ring. BUT, it has no spring characteristics to keep it pressing outward to create a seal. Instead, it has an O-ring underneath the compression ring that provides all of the outward flex to seal the gas between the piston and cylinder wall.
- Teflon Rings Are Self Sacrificing: They provide their own dry lubricant as they wear against the cylinder walls. The good news here is that the rings are what wear out, not the cylinder walls nor the pistons. And the rings are easily replaceable. The bad news is that as they wear, they produce a teflon dust residue. And if there is any moisture in the incoming air, it mixes with the teflon dust and starts gumming up the ring movement. I made a BIG mistake when I replaced all the rings last year... I used some of that food grade silicon spray lube to make the new rings slide into the pistons easier. That's right, I introduced moisture where I should have kept it dry. Over the Summer of filling tanks, my rings got gummed up more and more until they stuck in an almost totally compressed condition. And that's what made my compressor pump so much slower.
- Slow Pressure Can Break Things: The 3rd stage piston on my RIX is "floating". It doesn't connect to its piston rod. The proper function is for the compressor to build pressure rapidly, forcing the 3rd stage piston to stay in contact with its piston rod. If this pressure doesn't build rapidly, the piston just gets hammered over and over until the pressure finally comes up. I believe this is what broke my 3rd stage piston. Now that I have the compressor running properly, I can actually HEAR the 3rd stage piston hit the piston rod once or twice before they settle into constant contact and become quiet. As was stated elsewhere, the first priority of the Back Pressure Regulator (on the RIX) is to build pressure rapidly so as to reduce hammering of the 3rd stage piston. I will add that its important to close all your drain valves before starting to assist in rapid pressure build.
- Keeping It Clean is Easy: Following the RIX tech's advice, I scrubbed the cylinders with Dawn detergent, hot water, and a green scotch brite pad with bottle brush back-ups. Rinsed with a fresh water squirt bottle and air blast several times. Then, I scrubbed the piston rings on the pistons with a nylon toothbrush and Dawn with hot water. Lots of black gunk came out. I scrubbed until the suds remained white. Then, rinsed with fresh water and air blast. I let everything dry fully before re-assembly. This cleaning process allows you to watch as the rings get freed from their gunk, they start to expand outward and you discover that they're still good rings... You don't need to replace them. And since the RIX has no crank case, popping the pistons out for an occasional ring cleaning is pretty easy. You wouldn't need to do this on a conventional oil-lubricated compressor. BUT a RIX is Different. :)
SurfLung
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Vintage Diving Technique are Why I Got Back Into Diving.

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Re: RIX SA3E

Tue Apr 02, 2019 10:12 am

Plumbing Experiments...
- I've been trying to clean up and make my plumbing more compact. This latest effort:
1. Removed the un-needed check valve.
2. Switched to a back mounted gauge.
Image
- It looks clunky to me. My original idea is to have a cross fitting coming out of the moisture condenser. But I ran into male/female fitting problems and had to do it with two Ts instead.
- Also, that last elbow doesn't look like it saves much on space. I could probably run the BPR straight out from the bottom elbow and only stick out an extra inch. Maybe I can angle it back a little... Problems arise with clearance for the rotation required to thread each piece on.
- I have a new T fitting on order with 3 females and one male. This should get it in closer to the moisture condenser. I can attach all three instruments to the T I think and keep the weight of them all as close as possible, too.
SurfLung
The Freedom and Simplicity of Vintage Equipment and
Vintage Diving Technique are Why I Got Back Into Diving.

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