Need help with Armstrong TR 21-12 problems please

[Bambi_Bandit]

Originally Posted by Top

Thanks for all the replies.
To explain things a little better, I have a very expensive 100' extension cord. It has 10ga wire in it and is capable of 20A delivery. It has a NEMA L-5 30 receptacle on the trailer end. 30 amps are not required to run the A/C. It is on a 20A circuit in the trailer CB box. The problem is not normal amperage draw, it is the GFCI.
Somewhere in the compressor wiring, I have a short to ground.

I hear what you are saying... but I had the same problem on my '08 last year. Drove me nuts, and it turned out to be the actual 20A circuit breaker in the trailer that was bad... Changed that and all was good. Only took me 2 weeks and multiple trips up on the roof poking around under the AC shroud to fix it.

[soldiermedic]

Originally Posted by Top

Not ridiculous. COOL!

It IS ridiculous Top.

Kevin needs to share the love and receive the wealth of Karma. I have big plans for the interior of that trailer.

Steve

[Lance M]

We took Abby on her first trip, post rear half restoration, to the Central Texas Rally this past weekend. The A/C worked fine most of the time. No popped breakers or GFCI problems at all. We were parked under some of the biggest shade trees I have ever seen. As long as the compressor stayed running all the time the trailer was cool inside. It was between 95-100 degrees F the whole weekend.
We did have one small problem one morning when the sun started to heat things up and the thermostat clicked to turn on the compressor. The compressor did not kick on and a few minutes later, my daughter was asking me why it was so hot in the trailer. I went to the thermostat and moved the temp selector to the left (90) then back down until I heard the click for the compressor to turn on. Nothing. Finally after three or four times of moving the temp selector back and forth the compressor kicked in and cold air started blowing again.
Any suggestions or possible causes?

[Lance M]

Bueller? Bueller? Anyone?

[Phrunes]

My guess is a faulty thermostat. Put a meter on your lines to check continuity and current and if all is good... I'd replace the thermostat and see if that cures your problem.

[Lance M]

I'll check that out. Thanks.

[loechli]

Originally Posted by Top

Thanks for the help y'all. I think I've fixed it. These two wires were draped down over the blower motor sitting in a puddle of water. The black rubber boot for the (capacitor? Relay?) Is all torn up and was puddling water where these two wires connect to the componnent.
I cut off the old blade connectors and used two of these $1.10 crimp/solder/heat shrink super connectors I bought at Fastenal. I did my best to seal up the top and sides of the rubber boot. I'll have to keep an eye on it. It seems to be working fine right now.
Thanks guys. Once again the Forum knowledge base comes through!

I am trying to find specs on the blower motor for my Armstrong TR 21-12 I can in your pictures your blower motor is 1560 RPM can you tell me the model and make, I need to replace mine and my tag is illegible.
I tried a blower from Granger 4UU33, but it is too slow RPM and gets very very hot.

[Lance M]

Originally Posted by loechli

I am trying to find specs on the blower motor for my Armstrong TR 21-12 I can in your pictures your blower motor is 1560 RPM can you tell me the model and make, I need to replace mine and my tag is illegible.
I tried a blower from Granger 4UU33, but it is too slow RPM and gets very very hot.

I'll have a look through my other pics to see if there is a better pic of the data plate. If not, I'll pop the shroud off and take a look when I get a chance.

[Lance M]

Originally Posted by loechli

I am trying to find specs on the blower motor for my Armstrong TR 21-12 I can in your pictures your blower motor is 1560 RPM can you tell me the model and make, I need to replace mine and my tag is illegible.
I tried a blower from Granger 4UU33, but it is too slow RPM and gets very very hot.

It is a FASCO type U18481

Hope this helps.

[loechli]

Thanks for the quick response, having a hard time finding the motor with part number you gave me, how long has it been on your system is it working well, does the plate on motor list HP or RPM?

[loechli]

Originally Posted by Top

It is a FASCO type U18481

Hope this helps.

Thanks for the quick response, having a hard time finding the motor with part number you gave me, how long has it been on your system is it working well, does the plate on motor list HP or RPM? I also saw in one of your pictures that you have a 4 speed motor I assume your wall thermostat is like mine with a High and Low, do you know which 2 of the 4 speeds you are using?

[Lance M]

Originally Posted by loechli

Thanks for the quick response, having a hard time finding the motor with part number you gave me, how long has it been on your system is it working well, does the plate on motor list HP or RPM? I also saw in one of your pictures that you have a 4 speed motor I assume your wall thermostat is like mine with a High and Low, do you know which 2 of the 4 speeds you are using?

It was installed in 2003 or 2004 I believe. The blower motor works just fine. It was installed by a PO that is an A/C guy. You can google M&M Refrigeration Buda, TX to contact him. Super guy.

The data plate shows it as a four speed. I don't know which speeds are used.
HP is listed as 1/6-1/8-1/10-1/12
AMP is listed as 3.2-1.7-1.3-1.1
RPM 1550 (4 Speed)

[Lance M]

Originally Posted by Top

We took Abby on her first trip, post rear half restoration, to the Central Texas Rally this past weekend. The A/C worked fine most of the time. No popped breakers or GFCI problems at all. We were parked under some of the biggest shade trees I have ever seen. As long as the compressor stayed running all the time the trailer was cool inside. It was between 95-100 degrees F the whole weekend.
We did have one small problem one morning when the sun started to heat things up and the thermostat clicked to turn on the compressor. The compressor did not kick on and a few minutes later, my daughter was asking me why it was so hot in the trailer. I went to the thermostat and moved the temp selector to the left (90) then back down until I heard the click for the compressor to turn on. Nothing. Finally after three or four times of moving the temp selector back and forth the compressor kicked in and cold air started blowing again.
Any suggestions or possible causes?

Hi,
I haven't posted on here in a while, but I come to look when I have problems
This problem above was a sore spot for many years, until I decided I needed to get this fixed. To get by, I just kept the thermostat down so the compressor was running all night. It would get pretty chilly some nights, but it was a good reason to cuddle up to keep warm.

It was in 2015 when I finally had enough.

I found the problem in this Essex contactor.

https://photos.app.goo.gl/cymHdYtzDTcVAD3Y8

Sometimes it would make contact and sometimes not. Intermittent problems are sometimes hard to find.

I managed to find a suitable replacement at Grainger.
The relay I used is P/N 6AZU2
There are many versions on Amazon. I carry a spare.

So I fixed a problem that had been around since we've owned Abby about five years later. Better late than never.

[Lance M]

I truly do love the Armstrong AC on Abby. I really do.
But, like most things, ACs only break when you need them.

We were on our way up north for a family reunion the week of Independence Day. We'd planned it for weeks and we were all set. We hadn't camped in Abby for almost a year so I made sure everything, especially the AC, was in good working order before we left Texas for Iowa. Everything was working wonderfully. Then-
We arrived at our first stop for the night after a beautiful drive. I hooked up the electric first to get the cooling going because July in Texas and Oklahoma are pretty hot and when I flipped the switch...nothing. I did some troubleshooting and after about two hours of wasted time we decided it was best to return home and figure out what we could/would do. So, six more hours of towing and we were back home.

I made the trip with my son for the family reunion without the wife and cats. It was a bummer, but my mom and dad were glad we made it.

So after I got back I found the control transformer was bad.


I call this Armstrong 'whatever' wiring. it makes me cringe.

Fortunately, these old Armstrong ACs use parts that are readily available.
I ordered a new Supco SXT105 transformer from Amazon. I had to install it externally because the new transformer is bigger than the original. Everything works well...sitting in the back yard with no travel plans anyway.
Let's make some plans and see what breaks next...

[J. Morgan]

My 72 Armstrong was AWESOME until about a month ago when the compressor finally went south. I can't complain, I worked it HARD for nearly five years even after it took the brunt of a lightning strike early last summer that took the capacitors out.

If it wasn't for the lightning, I think it would still be running today..... While it still cooled really well right to the bitter end, it never sounded quite right after the strike.

I was in the middle of a trip when it failed, so I replaced it with a Coleman...

I have a 13K compressor, and I WILL be repairing the Armstrong because it's awesome. [emoji4]

[Lance M]

J. Morgan,
Good luck with the repair!

[Lance M]

Not what’s supposed to be happening when there are places to go.

[Lance M]

Originally Posted by Top

Not what’s supposed to be happening when there are places to go.
Attachment 348937

Last year the old Armstrong AC didn't want to work too well. I replaced the small start capacitor and it seemed to have fixed the problem.

Good information on this thread-



We only went on one trip to the coast last summer, so I didn't notice any problems in the few short days we were at the beach. This summer on our first trip to the coast, again, no problem. The following month I took a bit longer trip to visit my parents in Minnesota for about 10 days. It was hot and humid the first few days and the AC was required. The second night the compressor cycled off as it should when it got to the set temperature. When it warmed up again I heard the thermostat click faintly but the compressor didn't kick in. I got out of bed and gave the thermostat a light tap and it clicked again and the compressor briefly started to run, but then stopped. I moved the temp slider back over to the high side and shut off everything and opened the windows. It was cool enough that AC wasn't needed for the remaining nights in Minnesota.
I had a nice shady spot-

We had another beach trip planned for the following month, so I needed to figure out what was the problem. Of course I read a bunch of threads here on the airforums and did some testing/inspecting consulting with my friend Paul of A&P Vintage Trailer in Paradise, TX. Intermittent problems are always hard to find, but I think I managed to find the cause of this problem. When the compressor wouldn't kick in, if I pressed on the face of the thermostat, it would start the compressor and it would run as long as I kept pressure on the thermostat.
So, when I took the thermostat apart, I found this screw circled in red was loose and not making contact all the time. I tightened up the screw and everything has been working fine since then!



Kinda strange for a loose screw in something like this, but I remembered that back last year in Oklahoma, when we had the aborted trip because of the control transformer, this well intentioned camper wanted to help get my AC working and took the thermostat apart. I guess he didn't quite get that screw tight.
Hopefully we get many more years of cooling out of the ol' Armstrong!

[Lance M]

On our most recent trip up Nord, the evaporator fan was a bit slow to start but eventually would start turning if I switched the fan to HI. I took the beautiful overpriced A/C cover off and had a look. the fan spun freely after sitting overnight, so I figured I'd try a capacitor. I went to the local AC supply house and paid for an overpriced ($20) China capacitor. It is a 5 MFD 370V capacitor. You can get the same capacitor from Grainger for about $6.
I also ordered a new fan motor from Zoro, just in case.
https://photos.app.goo.gl/152VohZASUXyTxp26
https://photos.app.goo.gl/jTUkBvxFiHTwHJjB8

[Lance M]

I knew it would happen eventually. Luckily it was when we were up north and didn't need AC.
As I wrote in my previous post, I bought a new motor from Zoro. Unfortunately I didn't pack it for the trip up north. I did manage to gen a new motor in Sioux Falls so it all worked out.

You have to cut the unused shaft off, but it was a very simple fix all in all.
Video of unit after repair


https://youtube.com/shorts/O346V6HomJA?feature=share


Just waiting for the next thing to break...