Random Maintenance Questions

For general discussion with your fellow Minuteman III crewdogs, maintainers and cops. Currently based at Minot AFB, ND, Malmstrom AFB, MT, and F. E. Warren AFB, WY. Formerly based at Grand Forks AFB, ND. Operational from 17 Apr 1970 to present. Share your stories and meet up with an old friend.

Random Maintenance Questions

Postby SAC Killer on Thu Apr 01, 2010 9:53 pm

I didn't find a good place for this so I thought I'd start a new thread.

Yesterday I babysat a tech who repaired my heat pump. And we got to chatting and I was telling him about the chillers in the sites. In my day, the refrigerant compressors at Wing VI, and presumably the other wings, used R-22. But that's no longer allowed in most cases, and I don't think it is made any longer. So I'm wondering what the system uses now, and did they get new compressors when (if) they got rid of the R-22?

I hope the sites got new compressors. We regularly sent dead ones to Ogden. A bad chiller was PMC-reportable to SAC. But we never had any spares, so we would end up with a bunch of sites PMC-reportable, but chargeable to the depot for "awaiting parts." And then when they got enough of the things, Ogden would open up some sort of maintenance line and suddenly fix all the compressors we had sent to them. And then, no more than 48 hours after we got 20 or more of them, the depot would start to hammer us because we had not installed them all right away.

Hey, we only had enough teams to install two a day, every other day! And that was if the diesel generator sets were behaving themselves! Gimme a break! The depot held onto the things for months! :shock:
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Re: Random Maintenance Questions

Postby Capt. Bill on Thu Apr 01, 2010 10:56 pm

It is not totally banned yet.

The Clean Air Act does not allow any refrigerant to be vented into the atmosphere during installation, service, or retirement of equipment. Therefore, R-22 must be recovered and recycled (for reuse in the same system), reclaimed (reprocessed to the same purity standard as new R-22), or destroyed. After 2020, the servicing of R-22-based systems will rely solely on recycled or reclaimed refrigerants. It is expected that reclamation and recycling will ensure that existing supplies of R-22 will last longer and be available to service a greater number of systems. As noted above, chemical manufacturers will no longer be able to produce, and companies will no longer be able to import, R-22 for use in new A/C equipment after 2010, but they can continue production and import of R-22 until 2020 for use in servicing existing equipment. Given this schedule, which was established in 1993, the transition away from R-22 to the use of ozone-friendly refrigerants should be smooth. For the next 10 years or more, R-22 should continue to be available for all systems that require R-22 for servicing.
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Re: Random Maintenance Questions

Postby ornurse362 on Fri Apr 02, 2010 2:48 pm

At el Forko Grande, we would occassionally get an entirely 'new' (refurished) LF brine chiller ... The chiller would sit in some bay until it was loaded on a flatbed to be hauled out and installed - a truly fun experience.

Anyway, after a while, these 'new' chillers had to be stored in a locked facility because some of the more inventive FMT team chiefs would scarf some of the more scarce replacement parts for their own personal bench stock.

Anyway, that's the way I remember it and YMMV.

SAC Killer wrote:I didn't find a good place for this so I thought I'd start a new thread.

Yesterday I babysat a tech who repaired my heat pump. And we got to chatting and I was telling him about the chillers in the sites. In my day, the refrigerant compressors at Wing VI, and presumably the other wings, used R-22. But that's no longer allowed in most cases, and I don't think it is made any longer. So I'm wondering what the system uses now, and did they get new compressors when (if) they got rid of the R-22?

I hope the sites got new compressors. We regularly sent dead ones to Ogden. A bad chiller was PMC-reportable to SAC. But we never had any spares, so we would end up with a bunch of sites PMC-reportable, but chargeable to the depot for "awaiting parts." And then when they got enough of the things, Ogden would open up some sort of maintenance line and suddenly fix all the compressors we had sent to them. And then, no more than 48 hours after we got 20 or more of them, the depot would start to hammer us because we had not installed them all right away.

Hey, we only had enough teams to install two a day, every other day! And that was if the diesel generator sets were behaving themselves! Gimme a break! The depot held onto the things for months! :shock:
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Re: Random Maintenance Questions

Postby Capt. Bill on Sat Apr 03, 2010 12:10 am

I would think a bigger concern would be if the brine chillers used sodium dichromate (hexavalent chromium) as a corrosion inhibitor in the brine system. Before it was known to be a carcinogen it was premixed with calcium choride which was then dissolved in water to make the brine used in chillers.
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Re: Random Maintenance Questions

Postby banjodog on Sat Apr 03, 2010 2:52 am

wblakeney wrote:I would think a bigger concern would be if the brine chillers used sodium dichromate (hexavalent chromium) as a corrosion inhibitor in the brine system. Before it was known to be a carcinogen it was premixed with calcium choride which was then dissolved in water to make the brine used in chillers.


They used sodium chromate. Don't know about the di- part; we never called it that.

The chillers never needed any attention that I remember. I believe the chiller r/r job was an EMT job and I never replaced any, nor heard of any being replaced.
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Re: Random Maintenance Questions

Postby Capt. Bill on Sat Apr 03, 2010 3:22 am

It is sodium dichromate, widely used up till the 1990s I am a chemical engineer so I know. The plant I worked at used in our brine chiller systems. If we had a leak in the piping and it got outside the containment areas we had to report to the EPA.
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Re: Random Maintenance Questions

Postby gordymichels on Sat Sep 25, 2010 2:34 pm

banjodog wrote:
wblakeney wrote:I would think a bigger concern would be if the brine chillers used sodium dichromate (hexavalent chromium) as a corrosion inhibitor in the brine system. Before it was known to be a carcinogen it was premixed with calcium choride which was then dissolved in water to make the brine used in chillers.


They used sodium chromate. Don't know about the di- part; we never called it that.

The chillers never needed any attention that I remember. I believe the chiller r/r job was an EMT job and I never replaced any, nor heard of any being replaced.


I remember numerous guys getting sprayed during chiller R&R's (Scott Wells, Mike Abbott etc..) during the early 80's. There was so much controversy about Dioxin (I'm no chemist) at that time they said that 60 minutes tried to get on the base to interview us.

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Re: Random Maintenance Questions

Postby Warrior Of the North on Wed Jan 25, 2012 11:15 pm

the LCF & LF brine chillers at GF was R-502 at least while I was there 85 to 88
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Re: Random Maintenance Questions

Postby meanmarv on Tue Oct 09, 2012 12:00 pm

Reading the thread there appears to be two separate chillers being spoken about, Brine & G&C. Brine Chillers provided a secondary heat removal vehicle (brine) ethylene glycol and water was its composition with an inhibitor which give it color that was circulated to launcher or LCC with heat removed by the mentioned refrigeration system. Brine Chillers R&R'd by FMT.
Sodium Chromate solution was used as cooling medium for missile guidance package at LF, mixed normally by PREL, with G&C Chiller R&R'd by EMT, checked-out at base by PREL on G&C test bench. Brine Chillers checked out same of Chiller test stand.
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