AC Troubles - Hard Start cap? Something else?

[LipschitzWrath]

Okay guys, new member, long time lurker.

The missus and I finally bought ourselves a 5er, a 2004 Terry Quantum Ax6. It's huge and we have had it out a couple times. Got a great deal on it and we love it.

Lately it's been getting hot enough that we want to use the AC and that's where the problems began. I am running two brand new Yamaha Ef2000isv2 generators in parallel (kinda), so I feel like I have enough juice. Other relevant details is I'm at 6500 feet elevation and the air condonitioning unit is a Coleman Mach 15k unit. My research indicates it has the factory start capacitor kit installed. Full model number is 8335b6764.

First let's clear up the generator thing. It appears I have a bad parallel cable that yamaha is doing a warranty on. The pins inside the cable broke off and I'm not sure I ever had true parallel capability. Maybe I did but everything I've been told is these generators shouldn't struggle at all to start this ac and I've been successful I think 2 out of 25 times.

Ideas? Could the factory capacitor be bad? Would adding an aftermarket (say spp6) cap help at all or is the factory set up about as good as you can do?

Do I need to get my refrigerant levels checked?

[pianotuna]

The reason for the larger size is there is a big capacitor inside the microair unit.

[gbkim]

Glad to hear this worked out for you.
I will get my MA wired in as I get other tasks done & will be testing to see if one of my EF2400is can run my 13K A/C.

Gene

[LipschitzWrath]

In reference to #3 above, terminals like this would probably work. These are referred to as "piggyback" terminals.







The factory splice that was there had a clear plastic sheath over it. This proved problematic as there was not enough room to put two wires in from one side. So even then, the above piggyback connectors would not really be usable without at least ditching this sheath.

Truth be told, the wire nut solution I used may be the most elegant unless you are willing to cobble together and insulate some specialty connector.

[LipschitzWrath]

UPDATE:

In a word - "success". I installed the MA last night and pulled the 5er over to my father-in-law's 30A shore power. I went through the 5 start sequence to teach the MA. All 5 starts were successful. I had no amperage indication so I have no idea what kind of current I was pulling, they just started. Also, I have limited experience getting the AC to start so I can't really comment on how it did compared to before the MA.

I then got my two EF2000isV2 generators out and hooked them up in parallel. Being ambitious like I am, I decided to try it right off the bat in ECO mode. Waited the obligatory 5 minutes, heard the generators spin up a little when the fan started, then spool up a little more when the compressor kicked on. No problem whatsoever. Repeated this at least two more times and the AC kicked on every time. Very happy with the purchase.

A couple observations:

1.) As compared to the older style enclosure that the MA used to come in (based on pictures), the new style enclosure is HUGE. I had almost no room to install the enclosure in my capacitor compartment. In fact, the MA, along with the compressor run and fan run caps are basically crammed in the compartment.

2.) By installing a male quick disconnect terminal on the MA's brown wire, I was able to plug it directly into the compressor's white wire without having to cut and strip the wire. My goal was to be able to return all the wiring to stock configuration if I ever sell the camper and get a new one so I can take the MA with me. I originally planned to stick the compressor start cap in the cap compartment, too, but there wasn't enough room (see #1 above). Instead, I threw it into a spare parts compartment I have inside the camper.

3.) Along the same line as #2, connection of the black wire from the MA did not follow along with their installation video, despite the AC unit looking exactly the same. Rather than a wire nut type connector like in the video, mine had this weird "double-male" connector and both the factory black and purple wires had female disconnects, just like the terminals that attach to the caps. While I had intended to do the job without cutting any wires, I could not come up with a way to make this 3-way splice without doing so. I'm sure terminals exist to do so, but nothing readily available near me. I went ahead and cut off the female terminals on the black and purple and twisted them together (along with the black MA wire) using a wire nut (and covered with electrical tape to avoid water intrusion). This is still reversible, just not as streamlined as I had hoped.

4.) I was lead to believe from the installation video that the MA came with an assortment of terminals. Mine did not come with any. Not a deal-breaker by any means, but I did have to source my own terminals.

5.) The AC starts without practically a hiccup anymore. Great. However, it appears that running the microwave while the AC is running is too much for the generators, at least in ECO mode. I am going to play around with it a little more tonight. I might be able to get around it by switching the fridge to gas. However, I was really hoping AC and microwave at the same time in ECO mode would be possible in ECO mode with 4000 watts of generator.

[LipschitzWrath]

otrfun wrote:
LipschitzWrath, the LRA on your 15k unit is 79 amps. That's extremely high even for a 15k BTU RV unit. Most newer 15k units have a maximum LRA of 70 amps or less.

I was wondering that. For grins I logged onto the Coleman site and looked at the specs for what they spec as the new model replacement for what I have now. LRA (depending on where you look) is listed at 61 or 63 amps. Using 63 amps, that's literally a 20% reduction in LRA. Sounds like I am partially a victim of a big, inefficient, older AC unit. If I ever had to replace my rooftop unit, I'd definitely take advantage of the newer, more efficient model, but for now I am stuck with what I have.

otrfun wrote:
In any case, to put things into perspective, two EU2000i's operating properly in parallel (the EU2000i's are the king of inrush current BTW) cannot reliably start an RV a/c unit with an LRA much higher than ~60 amps---with the Eco mode on. With the Eco mode off, I've seen them start units with an LRA up to 70 amps or so. Never tested a parallel set of EU2000i's with an LRA much higher than 70 amps with the Eco mode off. IMO, it would be touch and go.

I'm glad you said that. For a while there, I was wondering if I had made a grave mistake going with the Yami's but from what you're saying, I would still be having this problem.

otrfun wrote:
FYI, from my experience, a simple hard-start kit may reduce the LRA 10 percent or so, or drop the LRA from 79 to 71 amps. 71 amps is still quite high.

Are you saying a factory hard start kit? Or an aftermarket kit (like the SPP6)? My AC came with the factory kit and I have confirmed that the capacitor is good. In any case, it sounds like I might have made the right decision skipping over the hard start kits and going straight to the Micro-Air.

otrfun wrote:
If your a/c unit works well on commercial power, all should be good with the MicroAir. The MA should easily drop your LRA down to less than 35 - 40 amps. Not sure about the Yamahas, but one EU2000i can start/run some newer, more efficient 15k units with the MA installed.

I only have 15A available at my current house so I dunno how well the AC works on commercial power. Never tried it. And we may never know. Sounds like the first time I will ever try the AC on shore power is when I haul it over to my father-in-law's house (he has 30A at his house) to do the MA "learn" sequence. I dunno what I'd do if it won't start on shore power with an MA installed. I'd lose it.

FWIW, I reached out to MA today and spoke to a very helpful individual by the name of Roger. He was happy to answer all my questions. He echoed what was said here. That is, the LRA on this AC unit is one of the highest he's seen. There is probably nothing wrong mechanically with anything (AC or generators), this is just a VERY demanding situation these generators are being placed in.

My 5er has the generator prep package and now I know why they spec'd an Onan 7kW 240V...

He said that the v2 models of generators from Yamaha are much closer to the Honda's in terms of surge capacity versus the v1's. Not saying better than the Honda's (I don't want anything to do with that debate), just better than the v1 Yamaha's.

He stated that his understanding was a 10% power loss from the generators for each 1000' elevation above sea level (I'm 6700'). Sounds a little high to me (I thought it was 10% per 2000') but okay. He recommended jetting the generators for high altitude. There seems to be mixed reviews about that on the internet. Some people say they're fine as is, others say do it. Any opinions here? If so, where do I get parts? The folks at Yamaha didn't see fit to package a nice "high altitude kit" like Honda does for their generators.

Lastly, Roger and I got to the meat and potatoes of the discussion. Based on my application, he said he would expect to see a surge of 23-25 amps on startup with the MA. He is 100% confident that it will work. I asked him very directly if he though the MA would allow me to start the AC with both Yamaha's in ECO mode (paralleled together, of course) and he didn't even hesitate - "Yes". With the 5-second delay on the MA and the pulsing it does during those 5 seconds, the generators will be brought up out of ECO mode before a compressor start is even attempted. He also said once the AC does start, he would expect the generators to quickly idle back down to whatever is necessary to keep the AC running.

After all this discussion, I must admit I am very excited. Should know more Monday night, hopefully.

FYI, the installation video that Micro-Air has on their website is EXACTLY the same for my installation, so I can follow it to a T. That said, Roger also stated that you can send an email to help@microair.net with your AC model number and they will send you a specific wiring diagram for your application.

Sorry to be so long-winded, I just wanted this information available for others if they are having similar issues.

[otrfun]

LipschitzWrath, the LRA on your 15k unit is 79 amps. That's extremely high even for a 15k BTU RV unit. Most newer 15k units have a maximum LRA of 70 amps or less.

In any case, to put things into perspective, two EU2000i's operating properly in parallel (the EU2000i's are the king of inrush current BTW) cannot reliably start an RV a/c unit with an LRA much higher than ~60 amps---with the Eco mode on. With the Eco mode off, I've seen them start units with an LRA up to 70 amps or so. Never tested a parallel set of EU2000i's with an LRA much higher than 70 amps with the Eco mode off. IMO, it would be touch and go.

FYI, from my experience, a simple hard-start kit may reduce the LRA 10 percent or so, or drop the LRA from 79 to 71 amps. 71 amps is still quite high.

If your a/c unit works well on commercial power, all should be good with the MicroAir. The MA should easily drop your LRA down to less than 35 - 40 amps. Not sure about the Yamahas, but one EU2000i can start/run some newer, more efficient 15k units with the MA installed.

[LipschitzWrath]

Yeah, I'm pretty excited to get it hooked up and see.

Of course, I was telling my father-in-law about my trials and tribulations and he had to plant the seed of doubt in my mind.

"Well, maybe you're not getting rated output from one of your Yamaha's".

Gee, thanks, dad.

I might be buying a kill-a-watt meter and borrowing the wife's hair dryer and curling iron.

It sure seems like with 4000 watts surge capacity, I shouldn't be having this much trouble.

[marcsbigfoot20b]

LipschitzWrath wrote:

j-d wrote:
Since RV A/C, like room A/C and appliances such as Fridges and Freezers, are all Charged then Sealed:

1. If it ever ran and ran right, there can't be "too much" refrigerant. No way to get in and overcharge it.

2. If the compressor is getting sticky internally, The RLA (Running Load Amps) will go ABOVE the spec on the compressor tag. But this can also happen if the coils are dirty, fan(s) aren't working, or weather is really hot.

3. If compressor RLA is BELOW the label spec, then the refrigerant charge may be low, OR the compressor's valves could be weak. Low refrigerant won't cool well, but it may show up as icing on the Evaporator Coil. Poor Valves will show up as poor cooling, long run times, and a compressor that CAN start right after it's been running and shut down. The WHY is, the Head Pressure that normally has to bleed down before a re-start, is not as high in an A/C that has a compressor with weak valves.

Thanks for the info.

1. Didn't think about the fact that it was sealed. Sounds like the only real danger is getting some sort of leak and losing all your refrigerant.

2. I guess the only way you would know this is with some sort of amp clamp. However, from watching their videos, Micro-Air themselves admit that most consumer-grade instruments don't sample fast enough to capture the actual peak current spike. They devised their own instrument to do so.

3. Doesn't sound like low refrigerant would be my problem. I think the fact that I was able to get the AC started on the first shot was because the pressures were equalized. Subsequent attempts all failed, regardless of what else I shut off in the camper. This would seem to suggest (at least to me) that the valves in my compressor are okay. Of course, this is all just my theory and therefore {likely} subject to error.

I went ahead and placed an order for the Micro-Air 364. With the discount code (thanks again!) my total came to $282 shipped 3-day. I will report back after I install and test.

If I still can't get my AC to start, then I would think I would have some sort of major problem!

You will be amazed at how much more quiet the compressor is when it starts. I actually had to watch the 5 volt drop on the Kill a Watt meter to know when the compressor came on it was so quiet......no more HUMMMMMM

FYI there is a 5 second delay when it is commanded on and a 5 minute delay for restart.
When you go to calibrate it, after you turn it on, then off, when you turn it back on it will take 5 min to turn the compressor on every time. So the "cal" takes about 25-30 min.

[LipschitzWrath]

j-d wrote:
Since RV A/C, like room A/C and appliances such as Fridges and Freezers, are all Charged then Sealed:

1. If it ever ran and ran right, there can't be "too much" refrigerant. No way to get in and overcharge it.

2. If the compressor is getting sticky internally, The RLA (Running Load Amps) will go ABOVE the spec on the compressor tag. But this can also happen if the coils are dirty, fan(s) aren't working, or weather is really hot.

3. If compressor RLA is BELOW the label spec, then the refrigerant charge may be low, OR the compressor's valves could be weak. Low refrigerant won't cool well, but it may show up as icing on the Evaporator Coil. Poor Valves will show up as poor cooling, long run times, and a compressor that CAN start right after it's been running and shut down. The WHY is, the Head Pressure that normally has to bleed down before a re-start, is not as high in an A/C that has a compressor with weak valves.

Thanks for the info.

1. Didn't think about the fact that it was sealed. Sounds like the only real danger is getting some sort of leak and losing all your refrigerant.

2. I guess the only way you would know this is with some sort of amp clamp. However, from watching their videos, Micro-Air themselves admit that most consumer-grade instruments don't sample fast enough to capture the actual peak current spike. They devised their own instrument to do so.

3. Doesn't sound like low refrigerant would be my problem. I think the fact that I was able to get the AC started on the first shot was because the pressures were equalized. Subsequent attempts all failed, regardless of what else I shut off in the camper. This would seem to suggest (at least to me) that the valves in my compressor are okay. Of course, this is all just my theory and therefore {likely} subject to error.

I went ahead and placed an order for the Micro-Air 364. With the discount code (thanks again!) my total came to $282 shipped 3-day. I will report back after I install and test.

If I still can't get my AC to start, then I would think I would have some sort of major problem!

[j-d]

Since RV A/C, like room A/C and appliances such as Fridges and Freezers, are all Charged then Sealed:

1. If it ever ran and ran right, there can't be "too much" refrigerant. No way to get in and overcharge it.

2. If the compressor is getting sticky internally, The RLA (Running Load Amps) will go ABOVE the spec on the compressor tag. But this can also happen if the coils are dirty, fan(s) aren't working, or weather is really hot.

3. If compressor RLA is BELOW the label spec, then the refrigerant charge may be low, OR the compressor's valves could be weak. Low refrigerant won't cool well, but it may show up as icing on the Evaporator Coil. Poor Valves will show up as poor cooling, long run times, and a compressor that CAN start right after it's been running and shut down. The WHY is, the Head Pressure that normally has to bleed down before a re-start, is not as high in an A/C that has a compressor with weak valves.

[gbkim]

marcsbigfoot20b27 wrote:
If you decide on the Microair easy 364 at $299...type in airstream into the discount code, $40 off.....now $259

Thanks for the code.
I was planning on getting one sooner or later, so sooner.

[LipschitzWrath]

If I do go through with the Micro-air, it sounds like it's pretty likely to fix my issue. My question is that are there other problems that could be causing this, i.e. A compressor going out or something like that?

Can refrigerant levels (high or low) cause issues?

I'm just concerned that either the micro air won't fix my issue or it will somewhat fix my issue but it will be masking a more serious problem.

I really do like the idea of the micro air because (on top of starting the AC) it should give me more flexibility with other items while I am running the air. I really don't like the idea of having to shut a bunch of stuff off every time I want to run the air.

[LipschitzWrath]

marcsbigfoot20b27 wrote:
If you decide on the Microair easy 364 at $299...type in airstream into the discount code, $40 off.....now $259

Thanks very much! I'm kinda leaning that way. A new hard start cap kit from Coleman is 20-30 bucks. Coupled with the discount code you graciously gave me, we're getting a lot closer to $200. Since it replaces the start cap, I'm thinking it may just be a better idea to go that way.

[marcsbigfoot20b]

If you decide on the Microair easy 364 at $299...type in airstream into the discount code, $40 off.....now $259