Saturday, January 26, 2019

Unexpected Benefit

I mentioned earlier that I had cataract surgery... Aside from the obvious benefit of being able to see clearly in the distance without glasses (!), there was an unexpected additional benefit.

New vs. Old

The lenses in my eyes had discolored just like a piece of Lexan left in the sun - they had acquired a yellowish/brownish cast.  Of course since this discoloration came on gradually over the decades, and because I had no other reference, I was completely unaware of the change.  I thought everything was normal - a real testament to the adaptability of the human brain.

In the picture above I have tried to show the dramatic difference between the views supplied by my new left eye and my old right eye.  The view on the left is completely unadulterated - it is as the camera saw it.  On the right is my attempt to show how that same view looked thru my old eye (there is actually less brown and more yellow in the old view than I could get into the picture).  Yes, it is that dramatic!

In another week I will lose this reference, because I go in for surgery on the other eye.  And then once again everything will be "normal".  So it is only in this brief interim period that I can enjoy the difference between "old" and "new".

A clearer more colorful normal!


Monday, January 21, 2019

On Becoming a Refrigeration Tech

As I mentioned previously, and you may have read, Eolian's heat pump quit working due to lack of Freon.

Never fearing to tackle a new field, I ordered a 5 lb container of R-410a refrigerant and a syringe of leak-stop fluid compatible with R-410a.  Gonna find out if I can be a refrigeration tech...

Before I begin, some basics that I may have discussed before.

Here's how a heat pump works:
  • A compressor pressurizes Freon vapor.  This heats it up (feel that bicycle pump after blowing up your tire...)
  • The hot Freon vapor is passed thru a heat exchanger where it gives up its heat to the cabin air, and condenses to a liquid as it is cooled.  
  • The liquid passes thru a narrow orifice and is allowed to expand into a low pressure space (created by the inlet of the compressor).  This cools it down really cold.  
  • The cold gas is heated up in another heat exchanger , getting heat from sea water.
  • The re-warmed vapor enters the compressor inlet, and the cycle repeats.
Thus, the system extracts heat from sea water and delivers it to the cabin.

The problem aboard Eolian was that almost all of the Freon had leaked from the system, meaning that there was essentially 0 psi at the compressor inlet when the compressor was running.  With our current water temperature, the inlet pressure should have been around 100 psi.  Outlet pressure should have been 400 psi, but was only 200 psi.  When the compressor was not running, the system pressure was 150 psi, meaning that it was unlikely that any significant amounts of air or moisture had leaked in.

Clearly there was a leak - otherwise the Freon would still be in there.  Thus the reason I ordered some leak-stop.  This came as a blue liquid in a big fat syringe, with fittings to attach it to the low pressure tap in the system.

Here's what we did:
  1. Inject the leak stop:  Jane started the system, the inlet pressure fell to 0, and I injected the leak stop against the lack of backpressure.  I disconnected and Jane stopped the system.
  2. Hook up the Freon cylinder to the inlet port.  Jane starts the system again and the inlet pressure falls toward zero once again.  I turn the Freon cylinder over so that the outlet is on the bottom, meaning I will be injecting liquid.  I open the valve, briefly, and a shot of liquid Freon enters the system.  Inlet pressure rises briefly, and then falls again as the injected Freon evaporates and goes into circulation.
  3. Continue injecting bursts of Freon until the inlet pressure comes up to 100 psi.
Ta Da!  The heat pump is delivering hot air!

Too much is not good
But:  overnight, as the system cycled on and off maintaining out nighttime temp of 63 degrees, I noticed that the compressor was making an uncomfortable noise when starting up.  I assumed that I had over-charged the system, and the the compressor was inhaling a little liquid on startup.

A real refrigeration tech would have evacuated the system with a vacuum pump, and then charged it with *exactly* 1.45 lb of Freon. But I have no vacuum pump and no scale.

So I had charged until I showed the desired pressure on the compressor inlet, but I failed to look at the compressor outlet - it was nearly 450 psi. It should have been a little less than 400 psi. Aside from damaging the compressor by feeding it liquid, too much Freon in the system also meant that the condenser and evaporator would be flooded with liquid, reducing the capacity of the system to transfer heat.

I bled it down until the high pressure side read 400 psi.  Everything seems to be fine now.  Now the only question remaining is whether the leak-stop stopped the leak...  Time will tell.


Friday, January 18, 2019

A January to Remember

One down, one to go
January was quite the month!  In no particular order:
  • Eolian's heat pump quit delivering heat.  It didn't take too long to determine why...  Tho the Freon pressure was acceptable when the compressor wasn't running, the suction side dropped to 0 psi when the compressor started.  We're nearly out of Freon!
    Clearly there is a leak, otherwise the Freon would still be in there.  The operative question is:  Is this a recent, big leak, or is this a long-term tiny leak?  The heat pump is about 5 years old, so I guess either is possible.
    I have ordered and have been delivered of a 5 lb container of the proper refrigerant, and a syringe full of leak-stop.  Now all I need is the opportunity to load those into the system.  But...
  • Tho I am still recovering from the near-paralysis event I experienced late this summer, I had cataract surgery scheduled for January.  If you're not interested in this, skip ahead...
    A most interesting operation - takes about 15-20 minutes, and you are semi-conscious for the duration.  The room is darkened and you are staring into a bright light - you never really see the surgeon open your cornea, slide in an ultrasound probe that destroys your old lens and sucks out the pieces, and then slide in a new lens.  The anticipation is far worse than the operation.
    Here I am the day following - vision still a little cloudy and blurry - I was told to expect that.  But surprisingly, the view thru my new eye is quite different from my old one!  It is as if everything in my old eye is being viewed thru an amber/brownish filter.  Colors are much truer thru my new eye!  A huge and unanticipated advantage! 
    Other eye later in the month.  No more prescription sunglasses!  I can have Polaroid sunglasses!
  • The heat exchanger in our gas furnace at our log cabin developed a leak - we could smell combustion products in the house when the wind blew.  It was under warranty, but the labor was going to be $1700.  Thankfully, the technician that confirmed the perforation of the heat exchanger assigned the cause to under-sized ductwork - ductwork that the technician's company had installed.  They agreed to eat the labor charges, as well as to modify the ductwork at their cost.  That was completed this week.
  • Eolian's TV crapped out.  While we were watching it, it started to cycle thru red screen, blue screen, white screen, green screen, etc.  Nothing would break the cycle, including a last ditch bit of percussive maintenance.
    New TV ordered and installed last week.
  • Tho it has less than 50,000 miles on it, the rebuilt engine that our Suburban's Previous Owner installed in it is obviously failing.  Aside from a defective valve lifter that randomly turns it into a 7-cylinder engine, it consumes a half a gallon of water for every tank of gasoline.  I have found and fixed all the leaks (there were many), but the water consumption continues.  I presume that the intake manifold is leaking into an intake runner (there's no water in the oil).  I have the receipts from the Previous Owner's engine - he got a Chevy long block for $1000 - that is an amazingly low price - apparently too low in fact.
    So the Suburban goes into the auto hospital for a new engine.  My son convinced me that I should save myself for working on the classics in the shop:  65 Mustang, 68 GTO, and the current project, 1959 Impala. So somebody else gets to wrangle this one.
  • Oh, and I figured out how to make my Sailrite LSZ-1 sew successfully with Tenara thread...
And it's worth remembering, the month isn't over yet...

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