basement AC-I don't think 2nd compressor is working

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Neildds1

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Sep 7, 2016
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Are there some fairly easy tests (for an electrically challenged guy but willing to learn ) that I can do to test to see if my 2nd compressor works or not?
My basement AC works and cools very well.  On recent 90 plus and very humid days it stayed a comfy 74.  I checked the output temp yesterday and it was 48.6 degrees.  I don't see the amps on the EMS that other people have posted when their AC is turned on and the 2nd compressor kicks in.  When I turn the AC on the amps jump to 11-12 and settle back to 6-8 amps.  If I set the thermostat to 10 degrees cooler than the inside temp I don't see the amps spike up at all so I assume the 2nd compressor is not kicking in.  I have checked the breaker and that is on, on the EMS panel is states that there is power to the 2nd compressor, I change the filter often and I make sure the outside is free of debris and dirt.
Am I being overly concerned since the AC is working or should I look into the possibility that the 2nd compressor is not working?
 
Your ears are likely the best tool. When first turning on the air, the fan starts, followed by the first compressor, then followed by the second compressor. The two compressors start about 10 seconds apart or so to minimize current draw.

There are two circuit breakers for that AC normally. On a 50 amp machine, they are located on opposite sides of the circuit breaker panel, you could turn the second one off to amplify the difference in sound if needed.

My trailer with basement AC has a 30/50 amp site switch whose sole purpose is to turn off the second compressor should I be connected on a 30 amp site (no EMS circuit/amp meter).
 
Start your generator and shut off the water heater (electric heat mode) and watch your current - with both compressors working you should see 21 to maybe 23 amps. Like Stu mentioned if you listen carefully, there is a noticeable sound difference when #2 compressor kicks in.
 
Neildds1 said:
My basement AC works and cools very well.  On recent 90 plus and very humid days it stayed a comfy 74.  I checked the output temp yesterday and it was 48.6 degrees.
Click to expand...
Sounds to me like the 2nd compressor is definitely working. In my experience, 1 compressor = 15-20 degree differential & 2 compressors = 30-40 degree differential.
I don't see the amps on the EMS that other people have posted when their AC is turned on and the 2nd compressor kicks in.  When I turn the AC on the amps jump to 11-12 and settle back to 6-8 amps. 
Click to expand...
  When #1 kicks on, you will see the amp jump then back down. If called for, #2 should kick on within a minute with another amp jump and back down. You normally only see the amp reading on the panel when using 30a shore power of the generator. Mine has no amp display on 50a shore power. If you are outside when the 2nd compressor kicks on you will hear the outside blower stop briefly, then start up again. But that doesn't tell you for sure that #2 started, only that it tried to.

But again, with the temp differential you are reading, I have to conclude that your #2 is running. So, kick back and enjoy!!

 
afchap said:
Sounds to me like the 2nd compressor is definitely working. In my experience, 1 compressor = 15-20 degree differential between return air & output aid & 2 compressors = 30-40 degree differential.  When #1 kicks on, you will see the amp jump then back down. If called for, #2 should kick on within a minute with another amp jump and back down. You normally only see the amp reading on the panel when using 30a shore power of the generator. Mine has no amp display on 50a shore power. If you are outside when the 2nd compressor kicks on you will hear the outside blower stop briefly, then start up again. But that doesn't tell you for sure that #2 started, only that it tried to.

But again, with the temp differential you are reading, I have to conclude that your #2 is running. So, kick back and enjoy!!
Click to expand...
 
Thanks everyone!  I started the generator, turned on the AC, the fan started, #1 compressor came on and and the amp reading was 20 and settled to 13 amps.  About 30 seconds later the outside fan quit blowing and I could hear the generator bog down and the 2nd compressor kicked in and the amp reading has settled to 10-11 amps.  Now that I know what to listen and look for I assume the 2nd compressor is working given how well it cools.  Again, thanks!

 
Neildds1 said:
....About 30 seconds later the outside fan quit blowing and I could hear the generator bog down and the 2nd compressor kicked in and the amp reading has settled to 10-11 amps. ...
Click to expand...
With both compressors running (and the blower) you should be seeing a steady 21-23 amps.
 
I had the same problem 15 yrs. ago with my basement air.
Ran me around in circle for some time, even took it back
for poor A/C on a hot day. I paid them to till me it was
working fine.

After much ado, and a learning curve, I found that the
colemen thermostat was NOT picking up the second
compressor EVER TIME.
I changed the stat 14 yrs. ago and it is still working.

Now that I think about it wonder  it I had the 3/4 degree
higher set temp that is required...I still have the old stat
if you would like it, as I know they have been  out of
production for some time.

tenn.vol.
 
John, given that I should be seeing a steady 21-23 amps with both compressors running (I had the set temp 10 degrees below the actual temp), is the next step testing the thermostat? 
 
Yes, see if the thermostat is calling for #2 compressor which is easy to check. Refer to the C-M truth table on my ecobee write-up, meter P2-6 (orange) wire from the thermostat for +12V. P1-2 (blue/white) will be ground for the test. Just stick the meter probe into the appropriate Molex connector and set the thermostat way cool.

If you see +12V on the orange wire then the problem is somewhere past the thermostat.
 
John Canfield said:
With both compressors running (and the blower) you should be seeing a steady 21-23 amps.
Click to expand...

On my 02 Adventurer I only see the amps up to 23 and higher when plugged in to shore power and hear the 2nd stage kick in.
If I'm running on the Gen it never jumps that high. I also hear the second stage come on. I don't know 100% but I read that the panel doesn't read the second stage draw when running on the gen.
IDK, guess mine could be broken?
John
 
I am thinking that 23 amps. is 10 amps higher than my basement air.
As I remember with ever other draw CLOSE to 1/2 amps.
My draw with first compress will say 14/15 amps and once the second
compress kicks in it will DROP 2 or 3 amps.....

tenn.vol.
 
tenn.vol. said:
I am thinking that 23 amps. is 10 amps higher than my basement air.
As I remember with ever other draw CLOSE to 1/2 amps.
My draw with first compress will say 14/15 amps and once the second
compress kicks in it will DROP 2 or 3 amps.....

tenn.vol.
Click to expand...

Sounds like you have an issue with your Basement AC....only 1 compressor running....could be as simple as a start capacitor...if you go to the Air Excel website you can download the manual for you unit and do some troubleshooting.
 
I started the generator, turned on the AC, the fan started, #1 compressor came on and the amp reading was 20 and settled to 13 amps.  About 30 seconds later the outside fan quit blowing and I could hear the generator bog down and the 2nd compressor kicked in and the amp reading has settled to 10-11 amps.  Now that I know what to listen and look for I assume the 2nd compressor is working given how well it cools.
Click to expand...
With the comment above, plus the temp differential described in the original post, I have to wonder if the problem isn't in the display. Even with one compressor running, the amps are not what I have normally seen.  I have seen erratic display issues sometimes in my One Place Center, and this sounds like that kind of issue.

The only thing I don't see reported anywhere is a temp differential when one compressor is running (set the t-stat one-two degrees lower and then measure the output air temp) VS the temp differential when both are presumed running. That might be a good indicator.  If the output temp stays the same, only one is running. If the output temp goes down when both should be running, then the problem is in what the display is reporting.
 
Sorry,I may have misspoken. As I have only 30 amp in MH,
and when on Gen. power I have 50 amps.

On my 30 amp. MH, the amp. draw on 1st compresor
is 14 amps. when the second compressor comes on
the amp draw will drop to 12 amp.

When Gen. runs on shore power (30 amp) my amp
draw is high teens.

Sorry for the confusion.  tenn.vol.
 
tenn.vol. said:
On my 30 amp. MH, the amp. draw on 1st compresor
is 14 amps. when the second compressor comes on
the amp draw will drop to 12 amp.
Click to expand...
This is not normal ...nor is it possible! (I realize that is what it is telling you, but it cannot be what is actually happening). When the 2nd comes on the amp draw should go UP rather than dropping. Adding a load cannot drop the amp usage unless other significant loads drop out at the same time.  And the 14a displayed for the 1st compressor is not normal either. All I am familiar with are a few amps higher. Mine is apx 17a for the 1st, and apx 24a with both running. Of course, we all normally have a few other things pulling power for those readings vary a little from one coach to another. BUT, all those quite unusual readings is why I believe your panel is not correctly displaying your amp draw.
 
Just had this problem about a month ago,Air wasn't working like it should,Ask a couple questions on here and had a friend come over to look at it.He said 2nd compressor wasn't working.He jumped the thermostat and the 2nd one kicked in,I ordered a new thermostat and the new one came with 4 wires instead of 3.Called colman and the tech  said cut the plug off the old one and use the same wires and don't use the 4th one.Works like a charm now
 
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