Looking for input on Micro-Air EasyStart installation failure

[BVJandJ63]

Thanks to you both, Dutch Master and Marvin!

Yes, Dutch Master--as Marvin pointed out, I posted last night the results of my testing yesterday in which we verified that, when disconnecting the RJ11 cable from AC/Zone 2 unit, I get the appropriate display for AC/Zone 1 on the CCC thermostat. So Zone 1 seems to be working properly.

So I'm thinking something is wrong on AC/Zone 2 unit. But after reading your post, Dutch Master, I see that there was a flaw in my troubleshooting--if 12V power only gets to Zone 2 unit by way of the daisy chain from Zone 1, then I'm not sure how to troubleshoot Zone 2 because when I plug in the daisy chain RJ11 cord from Zone 1 and then plug in the thermostat, the thermostat comes up with "EE" and will not clear that error.

It's late right now but I will read up on your other thread to see what new things I can learn. I'm also planning to call Micro Air Support team tomorrow to see if they can help me determine if the Micro Air unit is DOA. I do recall (weeks ago now!) that when I first tried powering up these AC units (on Onan 8000 gen power), the thermostat kept going blank as soon as it tried to start up. And when I was up top while a friend tried kicking it on, I could hear a click (I think in the Micro Air unit) but that would be it before the thermostat display would go blank again. And when I tried the reset step on the thermostat, I got stuck where I could never get past the "EE" error so could not power on either unit from inside the coach. (And only just found yesterday that the thermostat does work if only Zone 1 is connected.)

I went back up again today after an exasperating experience with Dometic Support... the lady was SUPER nice and patient. But as she explained, they are not trained on their AC units and they don't allow "end users" access to their techs so I couldn't get any answers. She did send me more docs but I couldn't find my answer there, either. For example:

• She insisted that my AC units have heat pumps so they *must* have "HEAT PUMP" DIP switches but I confirmed that--at least on AC/Zone 2, that is not the case (picture attached).
• She insisted (as did a tech last week) that the furnace wires should be connected only to ONE unit--typically the front (Zone 1) unit; but I confirmed in an old picutre that AC1 has these 2 blue furnace wires and confirmed today that they are also connected on AC2. So the FURNACE DIP switch is turned on for both units (and was before I started this project).
• I did another (third) check to be sure all my wires are going where they are supposed to go per the Micro Air installation instructions. The only thing I could not confirm was the connections on the Penguin 1 compressor (to be sure that the wire colors match the Micro Air install instructions). I attached a picture of this, too--how do I know which is S, R, and C? I imagine it's correct but I can't swear to it...

So I'll go read the other thread tomorrow morning but, meanwhile, if any of this triggers a thought that could help me determine which is bad--the Micro Air or the CCC board/AC unit, I'm all "ears!"

Although it's supposed to be raining tomorrow and I'm taking it to a shop on Wednesday for maintenance and a few unrelated repairs so if I don't figure it out tomorrow, it'll likely be next weekend or beyond before I can get back to this.

Thanks again!
--Bill

[Dutch Master]

Hello MarvinG and others,
You are correct in your reply. However, Newmar does not use the "same strategy" as Tiffin where they provide 12 volts to each unit. As stated, Newmar only provides 12 volts to the front unit only. If for some reason the "comm link" is not in tack, then 12 power is lost to unit 2.

What a shame that the manufacture of the control board did not spend an additional 10 cents to provide a simple LED showing 12 volt on each board. This would go a long way in helping both techs and DIY people to help troubleshoot this problem of missing 12 volts. This comm link of using cheap and ineffective RJ-11 connectors, couplers, and wire is a travesty at best. Over time, it becomes "very finicky." Not "best in class" as any automotive wire designer will quickly tell you.

[MarvinG]

From your previous post: “I double-checked the wires against the diagram before I closed up. The only thing I could not confirm were the "C", "H/HERM", or "other (Fan)" designators on the top of the run cap (I didn't see any legible markings) so I did (I hope not incorrectly) assume that white wire cluster is "C" and red wire cluster is "H" (and brown wire is fan).”

I can’t tell from the pictures if you have it wired correctly but I suspect you do. The brown wire is indeed going to the fan from the run capacitor so you know that is the fan side of the run capacitor. The terminal with the most wires on it, white, is going to be the common on the capacitor, so the other side, red is going to be the hermetic (compressor).

Even if you had it wrong, I doubt that is what is causing your low voltage/board/tstat issue. Once you get the stat communicating again, if you then have trouble getting the unit to start and “train” then you begin looking toward the microair problem.

Dutch Master: I follow what you are saying, I’m asking/thinking, that if he plugged his stat into the comm wire going to the front unit, and it worked, then takes that same comm wire and plugs it into the rear unit, should that not get 12 volts to the board on the rear unit? If so, then testing with a known, good comm wire from stat to rear unit should work, assuming board and stat are both good. Correct?

If so, then I would want to make sure the test comm wire I’m using on the rear unit is put together correctly.

Regardless of whether I have it correct or not, I suspect if he follows your detailed troubleshooting thread he will arrive at the solution.

[Dutch Master]

Hello Marvin & BVJandJ63,
I am trying to figure out what you stated on your last post. This is what I have assumed:


1. If you remove the comm wire coming from Unit 1 (i.e. remove it from Unit 2 control board), and then plug it in to the T-stat (remember to reset it), the T-stat should "light up" and show Unit 2.


Your are correct - If the T-stat does light up, then the comm wire from Unit 1 to Unit 2 is "OK." What would this step provide? It means that the control board in Unit 2 is bad - i.e. 12 volt power required to make it work and communicate with the T-stat.


In the case where the T-stat does not light up, then you have a missing 12 volt power coming from Unit 1.


Hope this leads a "little more light on this subject" and helps out.



Best Regards
Dutch Master

[MarvinG]

Right. I was asking/clarifying because my understanding is that is what he did as you restated in your point # 1. Again if I understand correctly He did connect to Unit 1 via the comm wire (at unit 2 using the comm wire normally plugged into unit 2 but now plugged to his stat and to unit 1) thus connecting to unit 1 and the stat lit up and showed communication.

I am not clear on whether the stat normally connects to Unit 1 and daisy chains back to unit 2 on Newmar but or vice versa but am thinking out loud that now we should have power to unit 2 with the comm wire plugged back in. If he gets a comm error or no lit up stat by plugging the stat into unit 2 using a second comm wire, he does indeed appear to either have a bad board or bad comm wire from stat to unit 2. If he is using a known good comm wire to test unit 2 that would seem to leave only the board as defective on unit 2. (Or something causing a tremendous amount of digital hash. . . .)

I should back out now and let you and him continue because I clearly admit I am not nearly as familiar with the system as you are.

[BVJandJ63]

So to clarify--here is where I'm at (and I did read several other threads where Dutch Master helped out):

Originally Posted by MarvinG

<SNIP>...if I understand correctly He did connect to Unit 1 via the comm wire (at unit 2 using the comm wire normally plugged into unit 2 but now plugged to his stat and to unit 1) thus connecting to unit 1 and the stat lit up and showed communication.

Yes, you understand correctly. So I deduce from this that the front AC unit (Zone 1) is working fine. I also deduce from this that the cable between unit 1 and unit (Zone) 2 is working fine. But when I plug that cable in to the board on unit 2, then I get the EE error on the stat and cannot reset/clear that error to operate either unit.

I am not clear on whether the stat normally connects to Unit 1 and daisy chains back to unit 2 on Newmar...<SNIP>

Yes, this is the case on Newmar; and this is apparently (thanks, DM!) why I have no 12V power on unit 2 when I disconnect that comm/phone cable from unit 2.

...or vice versa but am thinking out loud that now we should have power to unit 2 with the comm wire plugged back in. If he gets a comm error ...by plugging the stat into unit 2 using a second comm wire...

So this is the same as going back and connecting the stat to the other end of the daisy chain--inside the coach where the stat is normally mounted, right? Using a second (known good) cable from the second RJ11 port on unit 2 would not provide any additional info--if the two units are connected via the daisy chain cable, I will get the EE error (and no additonal clues) when connecting at either end--is that right? One possible exception would be to plug the working cable from unit 1 to the *other* RJ11 port in case the connection is broken on the port that I was previously and currently using for that connection to unit 1... I'll need to try that when I get the rig back next week. (Thanks for making me think this through a bit more before spending the money for a new CCC board! =)

...he does indeed appear to either have a bad board or bad comm wire from stat to unit 2. If he is using a known good comm wire to test unit 2 that would seem to leave only the board as defective on unit 2. (Or something causing a tremendous amount of digital hash. . . .)

Going back to previous quote... I don't think connecting a replacement/jumper cable to unit 2 will help because I can't isolate it from unit 1 comm cable (from which unit 2 gets its 12v power). But I'm curious what you mean by "digital hash"... are there other things I should look for that might be causing that interference?

I should back out now and let you and him continue because I clearly admit I am not nearly as familiar with the system as you are.

Thanks for chiming in, Marvin! I've still got a ways to go but your input was definitely helpful and is appreciated!

I'm on the verge of buying a new board to swap in if I confirm that the comm cable from unit 1 does not work on *either* RJ11 port on unit 2 (and then send it back if I find that swapping ports fixes the problem). I'll report back next week after I get a chance to chase this a bit more...

Thanks to you both!

[MarvinG]

“So this is the same as going back and connecting the stat to the other end of the daisy chain--inside the coach where the stat is normally mounted, right? Using a second (known good) cable from the second RJ11 port on unit 2 would not provide any additional info--if the two units are connected via the daisy chain cable, I will get the EE error (and no additonal clues) when connecting at either end--is that right? One possible exception would be to plug the working cable from unit 1 to the *other* RJ11 port in case the connection is broken on the port that I was previously and currently using for that connection to unit 1... I'll need to try that when I get the rig back next week.”

I believe your logic is correct. To rehash: if your stat up front normally connects to Unit 1, and then daisy chains back to Unit 2, as I believe it does, then yes assuming: if you disconnect the comm wire to Unit 2 and now the stat communicates with Unit 1. And conversely, you take the stat back to the comm wire from unit 2 and feed back to Unit 1 and it works, as you said it does, then I have to agree that you have proved the stat works, the old installed comm wire from the stat to Unit 1 is good, and the old installed comm wire from Unit 1 back to Unit 2 is good. I believe that only leaves the board as Dutch Master mentioned I believe. But remember free advice is worth what you pay for it and Dutch Master has a better handle on your system than do I

“Going back to previous quote... I don't think connecting a replacement/jumper cable to unit 2 will help because I can't isolate it from unit 1 comm cable (from which unit 2 gets its 12v power). But I'm curious what you mean by "digital hash"... are there other things I should look for that might be causing that interference?”

This is actually why I got involved in this thread initially. Because after learning the system as it is installed in my uncle’s Tiffin, I discovered the real problem was digital hash (think kind of like white noise or static getting superimposed into your AC control system). Digital hash can obliterate or drown out the digital signals the wire should be carrying. I know this is rare but it happened in his Tiffin and in his case was caused by a fluorescent light. I know you said you don’t have fluorescents, but there is an outside and admittedly rare chance you have something else causing digital hash back there. If so, it PROBABLY would have caused a failure when testing Unit 1 using the stat and comm wire at unit 2 going back to unit 1. It could be a defective MicroAir unit but I don’t think so. I would say the chance of MicroAir causing hash is very close to 0%. I’m guessing you have a bad board that failed coincidentally with your MicroAir install. Just guessing until you prove my guess wrong or correct. As an aside, manufacturers can put in filters to protect against hash, but obviously at least the older units don’t seem to have any protection. Subford I believe in another thread on another issue, wondered if a standard auto RF filter would filter out whatever the issue was in that thread. I don’t know the answer to that but it is an interesting thought that has little help for you.

“I'm on the verge of buying a new board to swap in if I confirm that the comm cable from unit 1 does not work on *either* RJ11 port on unit 2 (and then send it back if I find that swapping ports fixes the problem). I'll report back next week after I get a chance to chase this a bit more...”

Your idea of a bad port is possible, though probably unlikely. I THINK, but am not 100% sure, that you can simply plug your comm wire into unit 2 on the other port and it should work as well as it does in the original port. I don’t think the board cares which port you use. If you do purchase a board and have a chance of returning if it isn’t the problem, you might try connecting the wiring with it hanging there not touching anything that can short, and see if it works. That way it won’t have installed screw marks if you need to take it back.

[BVJandJ63]

Originally Posted by MarvinG

I believe your logic is correct. To rehash: if your stat up front normally connects to Unit 1, and then daisy chains back to Unit 2, as I believe it does, then yes assuming: if you disconnect the comm wire to Unit 2 and now the stat communicates with Unit 1. And conversely, you take the stat back to the comm wire from unit 2 and feed back to Unit 1 and it works, as you said it does, then I have to agree that you have proved the stat works, the old installed comm wire from the stat to Unit 1 is good, and the old installed comm wire from Unit 1 back to Unit 2 is good. I believe that only leaves the board as Dutch Master mentioned I believe. But remember free advice is worth what you pay for it and Dutch Master has a better handle on your system than do I

Thanks for the confirmation. And, yes--I think Dutch Master is correct: all signs now point to the board.

This is actually why I got involved in this thread initially. Because after learning the system as it is installed in my uncle’s Tiffin, I discovered the real problem was digital hash (think kind of like white noise or static getting superimposed into your AC control system). Digital hash can obliterate or drown out the digital signals the wire should be carrying. I know this is rare but it happened in his Tiffin and in his case was caused by a fluorescent light. I know you said you don’t have fluorescents, but there is an outside and admittedly rare chance you have something else causing digital hash back there. If so, it PROBABLY would have caused a failure when testing Unit 1 using the stat and comm wire at unit 2 going back to unit 1. It could be a defective MicroAir unit but I don’t think so. I would say the chance of MicroAir causing hash is very close to 0%. I’m guessing you have a bad board that failed coincidentally with your MicroAir install. Just guessing until you prove my guess wrong or correct. As an aside, manufacturers can put in filters to protect against hash, but obviously at least the older units don’t seem to have any protection. Subford I believe in another thread on another issue, wondered if a standard auto RF filter would filter out whatever the issue was in that thread. I don’t know the answer to that but it is an interesting thought that has little help for you.

Interesting thought (about the filter)... hoping I don't have to go there, though. And also glad to learn that it's not likely the Micro Air unit that introduced such noise.

Your idea of a bad port is possible, though probably unlikely. I THINK, but am not 100% sure, that you can simply plug your comm wire into unit 2 on the other port and it should work as well as it does in the original port. I don’t think the board cares which port you use. If you do purchase a board and have a chance of returning if it isn’t the problem, you might try connecting the wiring with it hanging there not touching anything that can short, and see if it works. That way it won’t have installed screw marks if you need to take it back.

Yes, you can be 100% sure--the CCC board does not care which cable is connected to which RJ11 port. But this is why I'm thinking thee is a chance that the port/connector (to which the daisy chain cable from unit 1 is connected) *could've* been stressed during my install and, since the cable in the other connector isn't being used (is there only to daisy chain to a 3rd unit if one existed), I should swap ports to eliminate a bad port as the cause. You're probably right--not likely. But it sure would be nice (quick and less expensive)!

I'll find out when I get the rig back next week...

Oh, and great tip about testing the new board without mounting it first in case I need to return it. So you're thinking that I can simply plug in the thermostat to the new board *with nothing else connected* and the stat should light up properly? Or are there any particular wires on the existing board that I would need to also move to the new board before I can confirm/eliminstate the board as the cause?

[MarvinG]

You would need the comm wire from Unit 1 attached to the new board in order to power it up. In which case, I believe, with all wiring and unit 1 board working, it should work i.e. no error codes.

[BVJandJ63]

UPDATE: so both AC units are working, now, as are both Micro Air EasyStart units!

While I had it in for maintenance last week, I asked them to take a look to see what I was missing. There is a pair of wires behind the main harness on the second/Zone 2 unit (that I didn't notice) that were twisted together and were "capped" with a twist-on (most likely by whoever installed the new CCC boards when they upgraded the coach to the 5-button CCC thermostat controller). I guess the tech noticed the twist-on connector down behind the original/hard-start capacitor and so those two wires were touching metal. I'm betting I unknowingly worked it loose when moving the wire harness around to make the new wire connections to the run cap.

So problem solved and project complete! Thank you both for your insights--I'm sure that they will serve others, too, who stumble across this thread when running into their own Micro Air install issues.

Now back to my probematic Magnum Energy stuff... (separate thread).

[MarvinG]

Real glad you got to the bottom of that one!