Monday, July 23, 2012

One A/C Repair After Another

This year has just not been a good one for working air conditioning at our address.  Near the start of the cooling season, the Suburban’s lack of cool was traced to a leaky compressor shaft seal.  Within a week or so of that, the house A/C decided to blow out a relatively new start capacitor.  The house’s unit was fixed; the Mighty Burb was not.

Later in the season, a wire burned off the house’s air conditioner, and it took me two tries to get the repair right.  Last month, the Airstream’s original Armstrong TAC-110 air conditioner went out on our way to Key West.  Its repair had to be delayed until some totally unexpected (and REALLY unappreciated) floor rot in the camper was repaired.

When I finally had a chance to evaluate the Airstream’s A/C, it was found to be out of refrigerant.  After pressurizing the unit with dry gas, the condenser coils were doused with soapy water until a stress crack was found in one of the ¼-inch copper supply lines.  Now, the proper repair would have been to replace the short length of 45 year-old copper.  But unsoldering it from the equally old, un-replaceable condenser coil and silver-soldering a new piece in had a high pucker factor attached to.  I did not want to do it myself, and there was a distinct chance that even a skilled professional would have a problem.  So the area around the crack was sanded shiny, and gooped with JBWeld.

After allowing the repair to cure overnight, the system was then vacuumed down to a respectable 29 inches vacuum and allowed to sit, valved off, for a couple of days until I could arrange with my buddy Kenny to share some of his R22 refrigerant with the unit.

When I had the current compressor installed around six years ago, I remember the man who did the work whining about there being nowhere to run his gauge hoses and have the fan-air-directing cover on simultaneously.  Being able to do so was, he told me, important for good gauge readings.  His complaint bounced off of me at the time because I did not know as much about A/C as I do now, and I had offered him the unit’s original installation instructions for insight which he declined to read.  But he persevered through his adversity, and left the vintage unit cooling admirably.

While waiting for Kenny, the opportunity was taken to read the instructions.  Apparently, the end-user was supposed to drill two 7/8” holes in the side of the unit in which the hoses were to be routed for operation with the cover on.  A quick zing zing with a bi-metal hole saw, and the job was done.

Another cool thing about the instructions was that it listed the correct load, by weight, of refrigerant the system needed (2 lb, 2-1/2 oz).  Talking with Kenny about everything, he allowed that he didn’t like the JBWeld idea, and he did not own a refrigerant scale.  But he understood my concern about brazing onto an un-replaceable part.

Fortunately, someone else was able to loan me a scale.  After hearing that, Kenny just loaned me his bottle of R22 in return for two cases of beer.  We both thought it was a fair swap.

Right before going out to charge the system, I noticed the house was not as cool as the thermostat was asking for.  The house unit’s start capacitor had conked out again.  While there is another story attached to getting the unit running, for now I will just say a new capacitor got the house back in the cool.

After confirming the Airstream’s air conditioner was still at vacuum, the scale was toted top-side, and the correct amount of liquid refrigerant loaded.

The Airstream’s A/C recharge was different than the Suburban’s in that the Airstream sucked in the entire charge as liquid with the power turned off.  The Burb, during last year’s repair, had to take most of its almost five pounds of refrigerant with the system running.

After applying power, the antique unit immediately came to life & got down to business cooling the place down.  After allowing the system to stabilize, temperatures & gauge pressures were found to be surpassing the performance guidelines listed in the installation manual.  Although my work here appeared to be done, I decided to let the unit run overnight before buttoning everything up.

The next morning, there was neither cool in the Airstream, nor pressure in the middle-aged refrigerant lines.  Re-pressurizing again, the previously JBWelded area was found to be okay.  But a “spot” upstream of the treated area was blowing soap bubbles like no one’s business.

While I have no idea why it waited to go bad, the copper line obviously had to be replaced now.

Having more regard for Kenny than the fella who did the compressor R&R, I got Kenny to lug his oxy-acetylene rig over.  Of course he had to rib me the JBWeld repair, and act like he thought I was not telling the truth about the new leak path.  But he did understand why I was hesitant about anyone working on antique parts.

Other than tight working quarters, Kenny had little trouble with replacing the defective length of plumbing.  After letting the repair cool, the system was charged with 200 psig of nitrogen, and valved off.

The next afternoon, after the A/C was found to still be holding 200 psig pressure, it was tripled-purged/vacuumed before being recharged with R22.  Once again the unit fired right up and got busy cooling.  But unlike last time, the unit is still running several days later.

The Suburban’s A/C has not been repaired simply because the high cost of gas has knocked the truck out of the towing lineup – It has been relegated to pushing the boat into the boat’s parking spot via its front-mounted receiver hitch.  Also, the repair itself will be expensive - $300-$700 depending on whether new or rebuilt parts are used.  I’m not in a rush to spend that much money right now.

In a new worry, the two house air conditioners and the Airstream’s A/C all use R22 as a refrigerant.  R22, while still legal to sell, is no longer manufactured, and the price keeps going up.  A 30-lb bottle of R22 used to be around $125.  It’s now going for $390.

For now, I’ll just keep playing the cooling game by ear.  But I sure do hope I do not have to pull out my gauge set anymore this summer.


Saturday, July 7, 2012

Only Eight Years Between Failures?

At the end of last year’s camping season, I noticed what appeared to be a small soft spot in my Airstream’s floor next to the aft wall near the bathroom sink.  After a very casual inspection revealed no smoking gun, I decided to do nothing about it just then.

Well the spot grew over the winter, and after our last camping trip, it was obvious something had to be done, and I was far from happy about addressing the area again.  This exact same area was rotted out when I got the camper eight years ago, and the entire bathroom was re-decked to fix it.

The wood/aluminum/bumper interface at the aft end of a 1967 Airstream looks like a rot problem waiting to happen.  As a consequence, many extra steps of sealing & caulking were done during the initial refurbishment to stave off potential water intrusion.  Obviously, more should have been done.

Now, the floor was re-decked back then with Oriented Strand Board (OSB) which I know is not many people’s favorite.  But any wood product will eventually rot if left to soak in water and that is exactly what happened here.  To keep the sheet-vinyl floor covering from splitting at deck seams due to vibration, the covering had only been glued down at its perimeter.  Once water leaked a path through the four-inch or so glue bond, it became trapped between the linoleum & decking.  The clock had apparently started ticking long ago.

The only way I knew to re-deck the floor back then was to take everything out of the bathroom, and the only way to do that was to take everything out of the camper because the bathroom had been built first.  Although I wanted to do a good job on the repair, disassembling the whole works this time around had no appeal.

The tub, due to its size, was the major stumbling block.  Now that I’ve “been around the block” with bathroom repair, a close look was taken.  Sure enough, the tub, after un-riveting, could be propped high enough to allow unfettered access to the floor.  The sink was similar in that the countertop could be raised high enough to remove the base cabinet.

The black tank, since it is mounted directly beneath the bathroom floor, had to be removed.  Although the removal was painless, I was surprised at the condition of the metal box in which the tank sits.

While everything was dry, it was obvious that water had been trapped between the tank’s insulating Styrofoam and the box bottom for quite some time.  New eight years ago, the galvanized box had heavy rust pitting.  Many years ago the freshwater hose connection leaked into the box during a night of camping.  While that may have been what caused the damage, I have never been comfortable with the camper’s belly skin covering the bottom of the box – too many opportunities for trapped water leaking past the rivets which hold the box together.

With everything out of the way above & below deck, the floor was cut out back to good wood with a jigsaw.

Normally, I enjoy working with wood, and have enjoyed countless projects which required building or rebuilding something out of wood.  New wood was NOT going to be part of this repair.  Eight years between failures is WAY too short.  So new decking was not cut for this project; it was cast… with non-rottable Fiberglas & resin.

To provide a solid interface with the existing decking, dowels were drilled on 1-inch centers.

Caulk and hot glue were used to make the Airstream resin-tight.  A plastic-covered, ¾-inch piece of plywood held in place underneath with a service jack formed the mold’s bottom.

The going-in plan had been to use many layers of custom-cut fiberglass mat.

But the work area proved to be too big, and smaller, random size strips were used.

Although the plan had been to make an all-fiberglass repair, a volume calculation indicated that slightly over three gallons of resin would be required.  Deciding I didn’t want to have slightly less than a gallon of resin left sitting on the shelf, a 3/8-inch thick piece of plywood was cast into the project as filler (trust me – I made triple-sure water could not get to it).

I went to the paint store originally to buy a SEM-brand rust neutralizer.  But I came home with a quart or POR15 black.

I had never used POR15 before.  But I like it, and will use it again.  Hopefully, I will remember to wear gloves, though.

Reinstalling the black tank was a high-water mark for the project.

Fortunately, some of my original construction marks for locating the tank were still present, and cutting floor holes for the toilet & vent did not have the same pucker factor it had eight years ago.

Although the resin appeared to be self-leveling during buildup, its thickness across the repaired area ranged from 5/8” (the goal) up to ¾”.  The extra thickness around the toilet’s closet flange was not a good thing as the flange did not screw in far enough to give me a warm fuzzy.

After making sure the toilet gasket could accommodate the next step, a router guide of 1/8” hard-board was weighted down, and the smallest router I had was pressed into service with a ¾” straight bit to recess the deck an eighth of an inch.

To any woodworkers reading, I got that Craftsman router new when I was in high school in the seventies.  Unlike newer routers with soft-start, this one jerks when switched on.  I’ll never part with it.

The decking was belt sanded before and after wiping with a small amount of leveling compound.

When the floor covering was originally installed, I remember the edge of the roll advising “do not reverse”.  This seemed odd because the pattern was square-shaped.  But since there was more than enough material, reversing was not an issue… then.

Although the scrap of the original material I had saved had enough square feet, it was irregular in the wrong direction – I had to reverse the pattern.  To my surprise there is a difference.  But due to the bathroom’s small size I do not think it is eye-catching.

Every square inch was glued down this time and J-rolled.  Bricks weighted down the seam and ends until the glue could set up.  A seam sealing kit was used afterwards.

While all this was going on I went around with an ice pick to make sure there were no other rotten floor issues – might as well fix everything now.  Thankfully, no other problems were found.

Since I’m still running the original stove, refrigerator, oven, furnace, and water heater, it’s anyone’s guess as to what will need repair next.  At least it will not be the bathroom floor for the foreseeable future.


Thursday, July 5, 2012

Scientology and the Art of Dryer Repair

One of L. Ron Hubbard's books lent great support to the other week's task of getting our dryer to quit sounding like it was drying a patrol's worth of combat boots instead of ordinary clothes.

 To service just about everything on late-model Maytag appliances, the front panel has to be removed. In this case, the drum was left unsupported. Although I have forgotten 99% of "Dianetics", one passage did come to mind, "Recalling the dramatic and overlooking the important, man has conceived himself, to be an object of chaise by necessity and pain... Whatever there is of necessity is within him."

To me this translates, roughly, into "Necessity is the mother of invention". Mr. Hubbard's book filled most of the void left by the panel's removal.

The extra noise was found to be coming from the squirrel cage fan - it was spinning freely on the motor shaft. A 'flat' which keys the fan to the motor shaft had disappeared from something like 16 years of use. Fortunately, the replacement part's mounting junction appears to have more 'meat' in that area.

All's quiet now. Perhaps I should use the peacefulness to re-read "Dianetics"...