Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
 


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 06-23-2009, 08:38 PM   #1
2 Rivet Member
 
Gael79's Avatar
 
1970 31' Sovereign
Lombard , Illinois
Join Date: Apr 2008
Posts: 93
Armstrong TR21-12 Help Please?

Hello All,

Looking for advice from someone who has actually worked on this model A/C unit. Symptoms are Fan runs, but compressor either strains or starts for a few seconds, and cycles on/off at regular intervals. I downloaded a manual from this forum (the odd/even page manual) but it shows a separate start and run capacitor. I found one large capacitor on the left rear side, just behind the compressor. It is oval and about 10 inches by 4 inches by about an inch wide. It has 4 terminals, and looks like 3 caps in one. The side of the cap calls out the 4 terminals as com, fan, fan, and Herm. 7.5, 7.5 and 30 uf. I assume that the Fans are for the condenser and squirrel cage fan motors, and the Herm is for the compressor.

The manual (wrong model) shows a start cap, but I cannot find it on the outside of the unit. I have not removed the inside shroud yet, or opened up all the sheet metal up outside yet, but cannot imaging why the cap would be anywhere else than near the compressor.

I have a neat cap checker at work, that will run rated voltage through each terminal, and report actual capacitance, so I'm taking the cap I found in and see if the three internal caps are O.K.

I need the advice of someone who has worked on this model before. Should I be looking for a start cap, or does this unit have a combined start/run cap, labeled herm?

Any other advise would be appreciated.

Thanks!! It sure is getting hot out. If it is a cap. relay, or something easy, I'll try to save it. If it is the compressor, I'm gonna roll the whole unit right off the top, and replace it.

Overall, the oher parts look O.K. for being 39 years old.

Thanks again for the help!!!
__________________
Scott

I have a picture of my Airstream in my wallet, and I'm sitting on it...

...If that's not love, I don't know what is!
Gael79 is offline   Reply With Quote
Old 06-24-2009, 03:52 PM   #2
2 Rivet Member
 
Gael79's Avatar
 
1970 31' Sovereign
Lombard , Illinois
Join Date: Apr 2008
Posts: 93
O.K., In case any of the 19 people that read this post are interested... The Multi taped capacitor checked out 100 % functional at work today. I was told by one of the guys in the HVAC dept. that if the compressor has 3 wires running to it, and it does, than there is a common, run and start circuit. If there is a start circuit, than somewhere there is a capacitor. I guess I'll start tearing things apart later this week, when it cools off a bit, and see what I can find. Still could be the compressor, and I don't believe it would be worth the money to fix this old unit.
__________________
Scott

I have a picture of my Airstream in my wallet, and I'm sitting on it...

...If that's not love, I don't know what is!
Gael79 is offline   Reply With Quote
Old 06-24-2009, 03:58 PM   #3
Rivet Master
 
Diesel1's Avatar
 
1967 24' Tradewind
Wickenburg , Arizona
Join Date: Aug 2008
Posts: 547
Don't know if my 1967 is the same or not, but mine had a bad start capaciter inside a wiring junction box at the front of the A/C unit. Adios, John
Diesel1 is offline   Reply With Quote
Old 06-24-2009, 04:08 PM   #4
2 Rivet Member
 
Gael79's Avatar
 
1970 31' Sovereign
Lombard , Illinois
Join Date: Apr 2008
Posts: 93
Thanks John!!!
I'll keep looking. Do you remember if yours had this large capacitor for the fans, and run circuit, like I mentioned? What was the cause of you replacing the start capacitor? Mine runs the fans, then sounds like it is either humming, or turning the compressor for a few seconds, then quits, and tries again cycling over and over. Just wondering if I'm on the right track...

Thanks again,
__________________
Scott

I have a picture of my Airstream in my wallet, and I'm sitting on it...

...If that's not love, I don't know what is!
Gael79 is offline   Reply With Quote
Old 06-24-2009, 11:19 PM   #5
Power to the People !
 
Maryw164's Avatar
 
1972 31' Sovereign
SAN DIMAS , California
Join Date: May 2008
Posts: 447
Images: 1
Blog Entries: 5
Send a message via AIM to Maryw164 Send a message via Skype™ to Maryw164
Manual

We have the same model in our '72. We will be replacing it with a new Carrier Air V soon. If you lived closer I'd offer it to you to use for parts, but IL is a bit far from Calif. It still works Ok, but in our 31ft AS a newer 15,000 btu will do a better job than the original 12,500 btu. Here is a manual I found on another thread, maybe it's better than the one you are currently using for reference. Hope you can figure it out. The one page was scanned backwards, so you'll have to rotate it to read it (not caused by me).

Ok, so I just realized this is the manual you already have, but maybe someone new reading this might have use for it.

Mary
Attached Files
File Type: pdf Armstrong Maintenance Guide - Odd Pages.pdf (576.4 KB, 578 views)
File Type: pdf Armstrong Maintenance Guide -Even Pages.pdf (636.3 KB, 462 views)
__________________
Happy Trailering !
Forums member #29232
Check out my new Blogs (work in progress):
https://www.airforums.com/forums/blog...-maryw164.html

https://1972airstreamsovereign.blogspot.com/
Maryw164 is offline   Reply With Quote
Old 06-25-2009, 12:36 AM   #6
3 Rivet Member
 
1967 26' Overlander
Fairbanks , Alaska
Join Date: Jun 2007
Posts: 110
Scott,
I am looking at my original paper work from my TR21-12 and the symptom you describe is written like this;
compressor does not run hums intermittentley cycling on overload.
Caused by
1. Low line voltage,
check and correction; check line voltage and see if it is over 10% lower than rated.
2. Motor starting or running winding open,
check and correction; Disconnect power. disconnect wiring at motor compressor terminals. Test starting and running windings for continuity. if test shows either side open motor will not start or run and compressor will have to be replaced.
3. refrigerant pressures not equalized;
check and correction; aloow 3 minutes for pressure to equalize and check for restriction in refer lines.
4. Motor winding grounded to compressor shell,
check and correction;If test shows continuity between metal shell of compressor and any one of the 3 compressor terminals the motor winding is grounded and the compressor will have to be replaced.
5. Run capacitor failure;
check and correction; replace run capacitor.
6.Defective start relay or start capacitor;
check and correction; replace.

I had mine apart last year and I think there are start relays in the unit form the inside. Take the cover off and open the metal box and you will find them.
Mine started after I shorted some of the leads, I think the capacitor leads are the ones that will check all your fillings in your teeth. Mine were fine but it did smart.
My neighbor is a refer man and he had a device with I think 4 leads on it , that tested the operation of the compressor. He is 80+ years old and would not look at it for me but gave me good direction.
I have original papers from my unit so if you have questions let me know.
Gary
Fishbone is offline   Reply With Quote
Old 06-25-2009, 09:48 AM   #7
2 Rivet Member
 
1972 25' Tradewind
Albany , Georgia
Join Date: Mar 2007
Posts: 33
Images: 8
I have a 72 Tradewind with an Armstrong and the start circuit is in a box on the side of the unit opposite from the compressor. (outside on the top)

Will
meadowlm is offline   Reply With Quote
Old 06-25-2009, 03:08 PM   #8
2 Rivet Member
 
1972 25' Tradewind
Albany , Georgia
Join Date: Mar 2007
Posts: 33
Images: 8
1000 words

Click image for larger version

Name:	ac.jpg
Views:	269
Size:	34.2 KB
ID:	82938
meadowlm is offline   Reply With Quote
Old 06-25-2009, 04:37 PM   #9
2 Rivet Member
 
Gael79's Avatar
 
1970 31' Sovereign
Lombard , Illinois
Join Date: Apr 2008
Posts: 93
Mary, thanks for your reply. Yeah I have those .pdf files, but like you said, if this helps out someone down the road, all the better!!! I appreciate your thoughts.

Gary, Thanks for your input as well. I'll run the list you gave me. I have tried this at a couple of different sites, and at home, and off of a generator that I have, so I don't believe the low voltage is an issue, unless I have a loose connection somewhere, that has high resistance, then maybe an issue. I'll let everyone know what I find...

Will, what can I say, a picture and everything. If I didn't know better, I'd swear you were over at my house yesterday, and took a picture of my trailer. That looks just like it! I saw that box, even took the last of the cowl screws out and removed the cowl from that side. It just never occurred to me that the start circuit would be located physically so far from the compressor. We are under a severe thunderstorm watch right now, or I would be out there opening the box right now. Airstreamer's are the nicest group of people - period. Will, thanks for the "KICK" (ha-ha) in the right direction.

I'll post what I find, but it may not be until the weekend, depending on the weather.

Thanks to one and all for the guideance!

All the best,
__________________
Scott

I have a picture of my Airstream in my wallet, and I'm sitting on it...

...If that's not love, I don't know what is!
Gael79 is offline   Reply With Quote
Old 06-25-2009, 07:15 PM   #10
2 Rivet Member
 
Gael79's Avatar
 
1970 31' Sovereign
Lombard , Illinois
Join Date: Apr 2008
Posts: 93
O.K., I opened up the box and here is what I found:
Click image for larger version

Name:	Picture040_25Jun09.jpg
Views:	217
Size:	201.1 KB
ID:	82948

Click image for larger version

Name:	Picture041_25Jun09.jpg
Views:	204
Size:	189.7 KB
ID:	82949

Click image for larger version

Name:	Picture042_25Jun09.jpg
Views:	223
Size:	213.3 KB
ID:	82950

Click image for larger version

Name:	Picture044_25Jun09.jpg
Views:	312
Size:	197.2 KB
ID:	82951

Click image for larger version

Name:	Picture045_25Jun09.jpg
Views:	271
Size:	223.1 KB
ID:	82952

I believe I'll take the capacitor in to work tomorrow and check it out, but I cannot believe that it or the relay are any good. Guess I'll be hunting for a relay. The paper insulator in this box is like a sponge. Very bad design. I may go back together with a weatherproof box here, if this fixes the unit.

I'll report more tomorrow...
__________________
Scott

I have a picture of my Airstream in my wallet, and I'm sitting on it...

...If that's not love, I don't know what is!
Gael79 is offline   Reply With Quote
Old 06-25-2009, 10:54 PM   #11
3 Rivet Member
 
1967 26' Overlander
Fairbanks , Alaska
Join Date: Jun 2007
Posts: 110
Scott,
I have been trying to find a shroud for my AC as mine was missing when I got it. I was told there are 2 different types of the same model. I thought nthat was strange but Wills picture confirms it. My start relays are inside the trailer. I have the receipt for the install in 1973 so it is about the same vintage but different. I'm glad you found the info you need and I appreciate Wills pics probably as much as you.
Will---Thanks a million!
Scott Good luck on your repair.
Fishbone is offline   Reply With Quote
Old 06-26-2009, 04:39 AM   #12
2 Rivet Member
 
Gael79's Avatar
 
1970 31' Sovereign
Lombard , Illinois
Join Date: Apr 2008
Posts: 93
Gary,
No problem!!! Your input is appreciated! Maybe down the road someone will read this thread, and your help will lead them to where their capacitor is (like your unit).

I am going to have to do some fiberglass work to my cover, if I can get it running right.
I saw that Inland has replacement covers, but I personally, am a little hesitant to spend the money, at least until this unit proves to be a runner.

All the Best,
__________________
Scott

I have a picture of my Airstream in my wallet, and I'm sitting on it...

...If that's not love, I don't know what is!
Gael79 is offline   Reply With Quote
Old 06-27-2009, 12:53 AM   #13
3 Rivet Member
 
1967 26' Overlander
Fairbanks , Alaska
Join Date: Jun 2007
Posts: 110
Scott,
All the treads I read about these AC units is they last longer than the new ones even when they are re-built. Your relay and coil are corroded by moisture and I will bet a bottle cap of your choice it will run with the replacement parts. A coil should run about $10 and a home AC repair should be able to direct you to a source near your home. I'm not sure about the relay.
Forum member TomW has a site 1967 Airstream Overlander. He shows great PICS on repairing his AC shroud with glass cloth and ABS cement. Check it out.
Gary
Fishbone is offline   Reply With Quote
Old 06-28-2009, 10:27 AM   #14
2 Rivet Member
 
Gael79's Avatar
 
1970 31' Sovereign
Lombard , Illinois
Join Date: Apr 2008
Posts: 93
Start Relay Needed - Ideas?

Hello All,

Even though the start Cap "tests" O.K., The relief hole in the top is open, so I will replace it with a like capacitor from Grainger ($8.00). I'll post P/N when I purchase and check to see if actually works.

I was getting goofy continuity readings on the start relay, so I decided to open it up. Check out the relay that I am the proud owner of...

The Service manual, (yes I have a copy PM me if interested) shows the relay as P/N 1890A13. The relay has General Electric and 3ARR3 K3S2 marked on it.

Has anyone changed this relay out with success, and do you have a good P/N and source?
I'll take it with me when I go to Grainger tomorrow. Once again, if I have any luck, will post results.

Thanks again to all who have got me this far. If this fixes the problem, and the a/c works, I'll have about $40.00 invested, and that includes a moisture proof enclosure to place these two components in.

Best to all,
Attached Thumbnails
Click image for larger version

Name:	Picture047_28Jun09.jpg
Views:	179
Size:	179.1 KB
ID:	83032   Click image for larger version

Name:	Picture048_28Jun09.jpg
Views:	204
Size:	187.3 KB
ID:	83033  

Click image for larger version

Name:	Picture049_28Jun09.jpg
Views:	267
Size:	195.5 KB
ID:	83034   Click image for larger version

Name:	Picture050_28Jun09.jpg
Views:	217
Size:	202.7 KB
ID:	83035  

__________________
Scott

I have a picture of my Airstream in my wallet, and I'm sitting on it...

...If that's not love, I don't know what is!
Gael79 is offline   Reply With Quote
Old 06-28-2009, 10:33 AM   #15
Rivet Master
Airstream Dealer
 
Inland RV Center, In's Avatar
 
Corona , California
Join Date: Feb 2002
Posts: 16,497
Images: 1
Quote:
Originally Posted by Gael79 View Post
Hello All,

Even though the start Cap "tests" O.K., The relief hole in the top is open, so I will replace it with a like capacitor from Grainger ($8.00). I'll post P/N when I purchase and check to see if actually works.

I was getting goofy continuity readings on the start relay, so I decided to open it up. Check out the relay that I am the proud owner of...

The Service manual, (yes I have a copy PM me if interested) shows the relay as P/N 1890A13. The relay has General Electric and 3ARR3 K3S2 marked on it.

Has anyone changed this relay out with success, and do you have a good P/N and source?
I'll take it with me when I go to Grainger tomorrow. Once again, if I have any luck, will post results.

Thanks again to all who have got me this far. If this fixes the problem, and the a/c works, I'll have about $40.00 invested, and that includes a moisture proof enclosure to place these two components in.

Best to all,
Grainger also has the relay.

Andy
__________________
Andy Rogozinski
Inland RV Center
Corona, CA
Inland RV Center, In is offline   Reply With Quote
Old 06-28-2009, 01:27 PM   #16
2 Rivet Member
 
Gael79's Avatar
 
1970 31' Sovereign
Lombard , Illinois
Join Date: Apr 2008
Posts: 93
Hello Andy,

Thanks a million! Do you happen to know what the current p/n is, or do they have the cross reference manuals on site?

Thanks again,
__________________
Scott

I have a picture of my Airstream in my wallet, and I'm sitting on it...

...If that's not love, I don't know what is!
Gael79 is offline   Reply With Quote
Old 06-28-2009, 01:51 PM   #17
4 Rivet Member
 
Distantdrummer's Avatar
 
1975 31' Sovereign
Houston , Texas
Join Date: Nov 2003
Posts: 494
Scott where did you get the manual?
Why not scan and post it (or link) here on site like someone was good enough to do with the later model manual.
Keep us posted with your results. Sure hope it works.
Armstrongs are awesome for their duration. Just think what other item could set up there in the elements for 40 years and keep on tickin. Not even a Timex.
__________________
__________________________
____ d'drummer ____

...aahh..rumm..pu..tum..tummm...
Distantdrummer is offline   Reply With Quote
Old 06-28-2009, 08:18 PM   #18
Rivet Master
Airstream Dealer
 
Inland RV Center, In's Avatar
 
Corona , California
Join Date: Feb 2002
Posts: 16,497
Images: 1
Quote:
Originally Posted by Gael79 View Post
Hello Andy,

Thanks a million! Do you happen to know what the current p/n is, or do they have the cross reference manuals on site?

Thanks again,
There are several different relay's that you can use.

Basically the start relay is a SP normally off device. (single pole)

The two big factors is the coil voltage, which in your case is 24 volts AC, and the currect carrying capacity of the relay terminals. As I recall it's something like 18 amps.

Andy
__________________
Andy Rogozinski
Inland RV Center
Corona, CA
Inland RV Center, In is offline   Reply With Quote
Old 06-28-2009, 10:36 PM   #19
3 Rivet Member
 
1967 26' Overlander
Fairbanks , Alaska
Join Date: Jun 2007
Posts: 110
Scott,
From the picture your relay got wet and shorted out and that's what cooked it. It took less than 30 seconds to fry it probably.
Continuity is a goofy thing with relays. When your Thermostat calls for air it puts 24V to your relay and it snaps, which then makes connection to start your AC and you will have voltage across two contacts. . So when you do continuity on a dead (no volt) you should have continuity across the other side only. Going from memory now. It is easy to test with VOM. Disconnect the wires going to the AC and turn the thermostat and find the 24v from Thermostat. Hook the wires to the relay and you should have 24v going to the AC unit.
The relay part number I have is 1890A13 from the Armstrong Service guide. The fan relays (2) is part 237-07. One for low speed and one for high speed.
I believe you can use any relay with the correct number of terminals and as long as it is rated for 24v and as Andy states heavy current draw. The Granger catalog shows a bunch with descriptions and the part number may not be the same.
I would be interested in the service manual if you can PM it too me.
Good luck,
Gary
Fishbone is offline   Reply With Quote
Old 06-29-2009, 04:43 AM   #20
2 Rivet Member
 
Gael79's Avatar
 
1970 31' Sovereign
Lombard , Illinois
Join Date: Apr 2008
Posts: 93
Manuals Coming...

Hello Gary,

Give me a day or two, and I'll post it on this thread. That way as suggested, all will have access.

This relay is not a contactor relay, it is a potential relay. It is a separate relay, not the low 24vac relay. I believe it is designed to engage when there is no (low) voltage across it, and disengage, based on the back voltage (EMF) that the compressor coils generate when spooling up to speed. There are only 3 wires going to this relay. It removes the start capacitor from the circuit, when the motor in the compressor is at about 3/4 of full speed. Most motors today have centrifugal switches that open up when the armature spins so fast to do the same thing.

I know of an appliance store in town that does A/C and heating work. I will try to get there today, and see if they have any insight.

Thanks to all,
__________________
Scott

I have a picture of my Airstream in my wallet, and I'm sitting on it...

...If that's not love, I don't know what is!
Gael79 is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Armstrong TR21-12 gonna fixey ??? pansy Furnaces, Heaters, Fireplaces & Air Conditioning 1 05-08-2008 07:08 AM
Schematic wiring diagram for Armstrong AC TR21-12, GO7series DMC Furnaces, Heaters, Fireplaces & Air Conditioning 4 10-06-2007 12:01 PM
Hello, looking for a schematic of the wiring in my Armstrong AC model TR21-12, DMC Member Introductions 1 07-10-2007 06:11 AM
armstrong a/c mike beech Furnaces, Heaters, Fireplaces & Air Conditioning 16 01-06-2007 05:31 PM


Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.



All times are GMT -6. The time now is 11:29 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.