Armstrong TR 21-12 running amperage

[BossCamper]

Does anyone know what the specs are for an Armstrong TR 21-12 A/C?

My old unit seemed to run good for a time, but now it has started tripping the breaker in the house.
I checked it today and found that the compressor ALONE, is drawing 12 to 13 amps, then increasing after 5 minutes, or so, to 15 to 16 amps. On a 15 amp breaker ... no wonder it is tripping the breaker!

Does anyone know what that unit should draw?

And what would be the reasons it has started drawing more?

I have thought about maybe too much head pressure from maybe the freon in it being dirty from scales in the lines after sitting for 15 years or so, not running. But I don't know if this is even a valid idea.

I've been happy thinking I won't have to get a new A/C, but now I'm not so sure!

Any insights?

Thanks in advance

[Inland RV Center, In]

Originally Posted by BossCamper

Does anyone know what the specs are for an Armstrong TR 21-12 A/C?

My old unit seemed to run good for a time, but now it has started tripping the breaker in the house.
I checked it today and found that the compressor ALONE, is drawing 12 to 13 amps, then increasing after 5 minutes, or so, to 15 to 16 amps. On a 15 amp breaker ... no wonder it is tripping the breaker!

Does anyone know what that unit should draw?

And what would be the reasons it has started drawing more?

I have thought about maybe too much head pressure from maybe the freon in it being dirty from scales in the lines after sitting for 15 years or so, not running. But I don't know if this is even a valid idea.

I've been happy thinking I won't have to get a new A/C, but now I'm not so sure!

Any insights?

Thanks in advance

A poor extension cord, can cause the problem

A low Freon level can cause the problem.

A dirty condenser coil, can cause the problem.

Internal trash in the freon lines? About 10 million to one, "NO".

The current draw increases, as the ambient temperature increases.

A 15 amp breaker, is not adequate. A 20 amp is specified by Airstream.

What is the temperature differential of the air immediately at the AC intake and exhaust? It should be, after a few minutes, 15 to 18 degrees.

Andy

[BossCamper]

I forgot ... the voltage at the trailer is 117 volts.

[Inland RV Center, In]

Originally Posted by BossCamper

I forgot ... the voltage at the trailer is 117 volts.

What is the voltage at the trailer, with the AC off, and then running?

Andy

[BossCamper]

Originally Posted by Inland RV Center, In

A poor extension cord, can cause the problem

A low Freon level can cause the problem.

A dirty condenser coil, can cause the problem.

Internal trash in the freon lines? About 10 million to one, "NO".

The current draw increases, as the ambient temperature increases.

A 15 amp breaker, is not adequate. A 20 amp is specified by Airstream.

What is the temperature differential of the air immediately at the AC intake and exhaust? It should be, after a few minutes, 15 to 18 degrees.

Andy

Thanks for the insights.

My extension cored is adequate.

The coils are clean, although I am considering getting a cleaner for AC condenser fins that will clean the oxidation off them. I'll have to get someone to check the freon levels. They could very well be low considering the age of the thing. On the AC in the inside it says 20 amp breaker maximum. the breaker box in the trailer has a 15 amp in it for that line.

I haven't measured the temp differential, but while it is running (sometimes for hours) it has to be at least 15 to 18 degrees, or even more!

Best guess so far is the freon levels. And I bet it is freon. I'll likely have to get it changed over to the newer refrigerant if I get a tech to look at it.

[BossCamper]

Originally Posted by Inland RV Center, In

What is the voltage at the trailer, with the AC off, and then running?

Andy

I didn't think of checking that ... With the AC off, it is 116.7 volts When I turn it on it drops to 102 volts!!
Not even close to being enough!
I'll have to look closer at my connection.

[Inland RV Center, In]

Originally Posted by BossCamper

I didn't think of checking that ... With the AC off, it is 116.7 volts When I turn it on it drops to 102 volts!!
Not even close to being enough!
I'll have to look closer at my connection.

Or, the size wire in the extension cord.

A "good" and proper extension cord, would not have that voltage drop.

As an example, a good 25 to 50 foot extension cord should be about 8 gauge, or better.

Andy

[Jammer]

Low freon levels lead to low amp draw.

Unlike automotive air conditioning systems, it is rare for older air conditioners to develop leaks or to lose refrigerant slowly over time.

Be sure you've checked the condition of the condenser carefully and be sure that there's good airflow across it.

[Distantdrummer]

Here is a thread link that has the manual for the TR-25-12 . (go to post #5 in the thread).
http://www.airforums.com/forums/f427...ase-52973.html
You probably have already seen it, but if not maybe something in the manual will add to your knowledge.
I have yet to find a manual for the TR-21-12 on the forums or any where else for that matter. It is sorely missed and much needed on these forums if anyone could scan & post the TR-21-12 or any other Armstrong manuals or data sheets.

[BossCamper]

Thanks for the manual. I hadn't seen it, so it will surely help.

[BossCamper]

Well, I've tried a couple of things. I have a SOB as well, so I connected it to the same cord plugged into the same outlet at the house and checked the voltage and it only showed minimal voltage drop between nothing on, and the AC running full, so I know it isn't my power connection. The cord is a regular RV 30 amp power cord, so I was certain it wasn't at fault.
Seems like the old thing is just drawing too much power
I have a nephew that is a refrigeration service tech for a local company. They do commercial stuff, but he should be able to figure something out for me. I think I'll impose on him and get some advice/repairs/whatever. I don't like calling on relatives and taking advantage, but what the heck!

[Mulligan]

Originally Posted by Distantdrummer

Here is a thread link that has the manual for the TR-25-12 . (go to post #5 in the thread).
http://www.airforums.com/forums/f427...ase-52973.html
You probably have already seen it, but if not maybe something in the manual will add to your knowledge.
I have yet to find a manual for the TR-21-12 on the forums or any where else for that matter. It is sorely missed and much needed on these forums if anyone could scan & post the TR-21-12 or any other Armstrong manuals or data sheets.

Hi, My 73 overlander has an Armstrong 21-12 fitted and although the service manual does'nt actually say 21-12 all the pictures look exactly like my A/C i'll happily scan and post online if it will help you. Tim

[ventport]

Originally Posted by BossCamper

I didn't think of checking that ... With the AC off, it is 116.7 volts When I turn it on it drops to 102 volts!!
Not even close to being enough!
I'll have to look closer at my connection.

You should still have 117 volts with it running if the extension cord was up to it's job. Before you spend a lot of time and $ why not try a heavier gauge cord as short as possible to get from the camper to the house outlet. The longer it is the more voltage drop you get.

[BossCamper]

Thanks for the advice.
I understand all that, and am my own worst enemy. The trailer is on blocks and can't be moved closer. I was using the 30 amp extension cords with a cheater adapter to plug into the 15 amp circuit in the house. I am embarrassed to say I had 5 25' cords! And to make matters worse, I had the polarity reversed!

I'm gonna wait till I get it back on wheels and move it closer and maybe even rig up a 30 amp circuit and test it properly.
I don't think there is anything wrong with the AC.

Thanks again

Loris

[loechli]

Originally Posted by Mulligan

Hi, My 73 overlander has an Armstrong 21-12 fitted and although the service manual does'nt actually say 21-12 all the pictures look exactly like my A/C i'll happily scan and post online if it will help you. Tim

I have the same airconditioner 21-12 on my trailer, I would really apreciate a scan of the service manual.

Steve

[Mulligan]

Originally Posted by loechli

I have the same airconditioner 21-12 on my trailer, I would really apreciate a scan of the service manual.

Steve

Hi Steve,
Sure no problem, let me have your email address and i send it to you
mine is tmulligan@ukf.net
regards

Tim