Onan 5500 Issues

[oneway]

White-red=5
White-bLack=1
Red-bLack = 4.1
W-r= cont
W-b=cont
R-b=cont

 

here is what I found on the roof with my meter...

[oneway]

So...

continuity between all points.

but white-red =5, white-black=1

the sum should be red-black =6.....

correct????

And I've got basically 4.0 maybe 4.1.

i disconnected the wires so I was reading only the compressor and no other capacitors online.

now I just re-read the "if the resistance of 2 equals the highest ohm reading".....

so if I apply that....then:

red-black=4

white-black =1

white-red=5

and that adds up.

 

[oneway]

Here is the schematic on the back of the AC.

So........input?

time for an A/C? Or smoke test the start cap with the PTCR???

 

[kaypsmith]

The compressor should have been read with everything, including the cap out of the equation. With that situation, your second try should be the correct one. Just a little 101 on ohms law, if two resistors are parallel, then the highest number will be reduced by the lowest, this would indicate that there is a breakdown between the start and run winding's and this will blow a cap. If the two are in series, the result  will be the sum of the two resistors, meaning that the two resistors are common only to common. Smoke test is certainly in order, just be sure that all wires are in the correct position, even if that means comparing to the second AC. Just be careful working with the capacitors, they will light up your life if you do not discharge them each time they are disconnected. Again good luck with the test.

[oneway]

I am careful. I make sure all power is off. I wear rubber gloves. I try to discharge the capacitor I'm taking out, and I use insulated pliers.

so test the new start cap with the intact PTCR is your recommendation?

[kaypsmith]

Yep, with the test results you should be good to go. Hope that all is well and it ends well, if so you will have saved a bundle. Persistency pays! I suspect that has been a beneficial learning curve. And thanks for the Blue angel photos they are great.

[kaypsmith]

Oneway, I'm sorry that I misread your second set of readings. They are still the same on both readings merely stated in a different order which indicates the compressor is bad. Smoke test will still be ok and we can always hope for the best. Note also on your meter, the setting for ohm reading is K ohm, that means that  for every 1. that you read is 1000 ohms, this is what was meant in another post that some meters will not read that low. I'm sorry that I didn't notice that and also you reported that all test read continuity? I'm used to reading a much more sophisticated vom.

7 hours ago, oneway said:

So...

continuity between all points.

but white-red =5, white-black=1

the sum should be red-black =6.....

correct????

And I've got basically 4.0 maybe 4.1.

i disconnected the wires so I was reading only the compressor and no other capacitors online.

now I just re-read the "if the resistance of 2 equals the highest ohm reading".....

so if I apply that....then:

red-black=4

white-black =1

white-red=5

and that adds up.

 

[oneway]

52 minutes ago, kaypsmith said:

Oneway, I'm sorry that I misread your second set of readings. They are still the same on both readings merely stated in a different order which indicates the compressor is bad. Smoke test will still be ok and we can always hope for the best. Note also on your meter, the setting for ohm reading is K ohm, that means that  for every 1. that you read is 1000 ohms, this is what was meant in another post that some meters will not read that low. I'm sorry that I didn't notice that and also you reported that all test read continuity? I'm used to reading a much more sophisticated vom.

I haven't put in the hard start kit yet to test it. I can do it in the morning but there is no sense in doing it just to watch it go up in smoke so more questions then.

1. Yes, I have continuity between all points. Red-white, black-white, and red -black.....I thought that was a BAD thing. Am I wrong?

2. I thought since white is common(which it shows on the schematic), then here is what I understood:

If red-white =5

And white-black =1

then I was supposed to find that red-black would read 6. Yes??

I have to admit my head is spinning a bit as this is my first attempt to understand all this.

 

[abyrd]

You should also check from each compressor terminal to Ground to determine if one of the winding is shorted to ground. 

You want a high resistance to ground,  all readings should similar.

 

Jim

[kaypsmith]

Jim you are correct.

[oneway]

So after more research with online videos and other sources here is where I think I am:

1.continuity test is good

2.  In the Ohm check:

Common to start and common to run should equal start to run, and start to run should be the highest number.( in my case the red-black)

This is where I believe my test fails.

agree?

[manholt]

oneway.

Thank you!  always puts a lump in my through...appreciate it... 

[abyrd]

Oneway,

 

Please check the resistance from each terminal to ground before you install your new capacitor.

 

Jim

[kaypsmith]

In the top of set of numbers you stated that white to red =5, w to b =1, r to b =6,  that is good. But later down you stated after you removed all wires and rechecked all which includes cap, w to r = 5, w to b =1, and r to b = 4, 4 is less than 5 that is bad. White being common/neutral, that is ground for testing purposes, so you are checking red to ground and black to ground in this point in the test. Red is start, and black is run according to your schematic. White which is common is ground when the circuit is completed all the way back to the breaker/fuse box. The outside of the encasement/metal is also supposed to be grounded all the way to the ground provided before it enters your coach, as this is the safety feature built into the electrical code. If common breaks down and leaks to the case of a device, it becomes a shock hazard, therefore you should not have continuity to the metal housing. Newer tools that have only two wires to plug in are made of a composite material such as plastic which is dielectric, meaning that it does not carry electricity and can not shock you, which is why the third leg can be eliminated,

[manholt]

What happened to the photos of the "Blue Angeles " ?

If we have a new moderator, that is anti military...I'm off this forum!

Carl

[kaypsmith]

Carl, you have to keep up! Go back a page, they are still there, don't panic.

[oneway]

3 hours ago, kaypsmith said:

In the top of set of numbers you stated that white to red =5, w to b =1, r to b =6,  that is good. But later down you stated after you removed all wires and rechecked all which includes cap, w to r = 5, w to b =1, and r to b = 4, 4 is less than 5 that is bad. White being common/neutral, that is ground for testing purposes, so you are checking red to ground and black to ground in this point in the test. Red is start, and black is run according to your schematic. White which is common is ground when the circuit is completed all the way back to the breaker/fuse box. The outside of the encasement/metal is also supposed to be grounded all the way to the ground provided before it enters your coach, as this is the safety feature built into the electrical code. If common breaks down and leaks to the case of a device, it becomes a shock hazard, therefore you should not have continuity to the metal housing. Newer tools that have only two wires to plug in are made of a composite material such as plastic which is dielectric, meaning that it does not carry electricity and can not shock you, which is why the third leg can be eliminated,

Well, first let me say Kaypsmith that you have been extraordinarily patient with me and I owe you particularly a beverage of your choice for helping me understand.

my ole brain is trying to come along for the ride and I think I've finally got it with that last explanation...maybe.

anyway, NO I didn't say...or mean to say that I FOUND red-black was =6

what I tried to say was that I thought I was supposed to FIND 6, but only FOUND 4 in the red to black wire measurement. That's why I provided the pictures of the meter readings.

and earlier before your last explanation while my head was spinning a little faster I thought maybe you were trying to tell me I was looking for this formula: 4+1=5

Now I believe I understand that the sum of each of the wires (red + black) , each measured  separately to common (white)..

should equal the measuring of red to black....

therefore if red to white = 5, and black to white = 1, the red to black should equal  6

Yet I only found red to black =4.

so I can go up  again to make sure the red or black doesn't have a dead short to ground now, but with my findings isn't that futile?

I hope anyone following this thread that doesn't have any electrical background is getting as much out of this as I am.

i sincerely appreciate it.

 

[kaypsmith]

No problem at all, glad to get the old brain taxed every once in a while. In an earlier post I mentioned ohms law 101 and eluded to parallel resisters versus series resistors, what I was referring to is the fact that there are two sets of winding. One being run winding (black), and the start winding being (red). Now both winding's are supposed to be common to common, in other words they are continuous , not a dead short, but with a resistive load (this is what makes electricity actually work) those readings were above ("zero" which is a dead short), they are still continuous but still connected to common, which is good. Now if the two of them are reading a number which is the sum of the two, they are doing what they are supposed to do they are working series. Now when you read start to run, you should be reading a higher number (the sum of the two), but if you read a lower number, this indicates a short between the two windings, not a short to ground but a short to each other, this is not what end result that we want to see.  The reason that I added the question mark after the cont comment,was my way of saying yes contnuity is wanted but not dead short, I don't know to high resistance your meter reads continuity. Don't get too far over your head but as I stated earlier I for one appreciate your willingness to learn, as this persistence is what make all of us to be better at whatever we endeavor to do.

[manholt]

Sorry, my bad.  I got behind, some where within 2,600+ coaches at Chandler, AZ.

This Post has turned around my thinking also.  Excellent !

Carl

[kaypsmith]

Here is a much better test for the AC compressor than the one that the op was using.

http://www.hvactrainingsolutions.net/troubleshooting-air-conditioning-compressor-motors-like-pro/

All of the readings are conclusive that the compressor is bad, remember that his ohm meter is calculated in 1K ohms, meaning that 5.0 is 5000 ohms 1.0 is 1000 ohms etc. Sorry that the unit will need replacing, but better than paying out big bucks for a generator that appears OK. Of course we haven't heard back yet about the smoke test. This also proves that testing rather than throwing parts at a problem is far better. Good luck oneway

[oneway]

8 hours ago, kaypsmith said:

Here is a much better test for the AC compressor than the one that the op was using.

http://www.hvactrainingsolutions.net/troubleshooting-air-conditioning-compressor-motors-like-pro/

All of the readings are conclusive that the compressor is bad, remember that his ohm meter is calculated in 1K ohms, meaning that 5.0 is 5000 ohms 1.0 is 1000 ohms etc. Sorry that the unit will need replacing, but better than paying out big bucks for a generator that appears OK. Of course we haven't heard back yet about the smoke test. This also proves that testing rather than throwing parts at a problem is far better. Good luck oneway

Yes,

the test results show a bad compressor and so I see no need to smoke test my new start cap.

I have had this thought:

I could go to the front (good) A/C and put in the new start cap there, then move the used but good start cap from that A/C and smoke test it in the rear (bad) A/C. I wouldn't feel bad if that went up in smoke.

the only thing keeping me from doing that is I don't want to take a chance on losing the good A/C for some reason until I can get home in about 3 weeks.

 

[kaypsmith]

Oneway, if you plan to replace the unit yourself, the job is relatively easy. While shopping for a replacement, I would normally suggest going from 13,500 to 15,000, but in your case since your RV is a 30 amp hookup, I would stay with a 13,500 to keep in sync with your present setup. Be sure to keep in mind that there is ducted and non-ducted units on the market, if your controls are overhead attached to the unit, that is non-ducted, and I would suggest replacing the inside control and vent at the same time, some are sold with and some without, be sure to keep this in mind. If ducted, "thermostat on wall", then replace with a ducted unit. Other post's about how to get it on the roof and safety precautions are all good pointers. Keep us posted, and PM me if I can be any help.

[oneway]

Thanks for all the help. My A/C's are ducted.

if I decide to tackle the job:

I have a friend with a decking around his house and a walkout basement. We can drive the Motorhome next to his house and put gravity on our side.

I think I'm gonna use the one A/C here until I get home to the cool mountains of California.

 

[wildebill308]

Goodluck and keep us updated.

Bill

[jleamont]

Great idea using the friends deck to help! The job is very simple, even with central ducting.