We've got two basement a/c units, both installed by Custom Coach. They appear to be custom units, and I cannot find a name plate on them anywhere.
Set up on both is the same and simple. Compressor and condensing coil below. Evaporator and air circulation fan above. Wall switch turns on air circulation fan and controls speed. Line voltage thermostat turns compressor on/off as needed. Don't see circuit boards or other electronics anywhere.
Problem started today when we tried to cool off the bus running on generator. Front a/c will start up and run for a few minutes, maybe five. It blows plenty cold during that time. Then the compressor cycles off. Only way to get it to come back is to turn off the breaker and wait about five minutes and then start over.
The other a/c unit works fine and just keeps pumping out cold air. This unit has worked well till today when outside temperatures hit high 90s.
I have little experience with a/c systems, so I am looking for ideas on how to troubleshoot and what to look for. Since it blows cold for a while, I'm hoping that means that the compressor is still working. Hoping the same for the refrigerant.
Any suggestions?
On my 1984 Eagle Entertainer, the basement combo A/C-electric furnace is by MemphisAire, which is no longer in business, just like Custom Coach. I'm surprised that some details of your units are not mentioned in all of the documentation they provided. Fortunately, many of the components of the units are used in other brands, and a good A/C shop should be able to come up with equivalents. The previous owner of mine replaced the circulation fan motor by going to an electrical supply house and getting a replacement with the same specifications. You should have a thermostat control ideally, that will let you set a temperature to maintain.
I believe there was a post fairly recently that had said one of the former Custom Coach people had a bus sales/conversion business in Marion, Ohio (or maybe Mansfield, OH). If you could reach some of the former Custom Coach people, they might be able to help provide clues. Custom Coach was active into the late nineties, at least, but at some point, they sold out to Farber Specialty Vehicles and became the Custom Coach Division of Farber. They are in a different building now, which is visible off I70 in Columbus, Ohio. If they were smart, they would have retained some of the employees, and the records of previous coaches.
It could be Cruise Air's I have a bus in my shop with front and rear units Cruise Air units. I haven't got to the point of testing them, but if they need fixing I do 'em.
Check to make sure your generator is putting out 60hz under load.
Quote from: TomC on May 26, 2018, 06:19:48 PM
Check to make sure your generator is putting out 60hz under load.
I'll check that. Is voltage as critical? Generator puts out 115, but with both a/c units running drops to 107.
Quote from: richard5933 on May 26, 2018, 06:43:02 PM
I'll check that. Is voltage as critical? Generator puts out 115, but with both a/c units running drops to 107.
Most electrical items today are designed to run +/- 10% or more, older components usually right at the 10% margin, so safe range would be 108-132. If they are inverter technology the acceptable voltage range could have a much larger swing. I have one device that is rated to run from 90-140 volts.
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make sure the fan on the cooling unit is working
dave
Quote from: richard5933 on May 26, 2018, 06:43:02 PM
I'll check that. Is voltage as critical? Generator puts out 115, but with both a/c units running drops to 107.
107 seems low to me,
Low volts allows the unit to pull higher amperage which generates more heat.
Hi Richard, try only running the one unit, that shuts off, alone and checking the voltage. If it runs longer or doesn't shut down, it's the electrical supply, if it shuts down about the same time, it's in the unit, lvmci...
What make/model of generator? The no load voltage is a little low and may be adjustable depending on what you have. The hz is dependant on engine speed.
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Quote from: thomasinnv on May 27, 2018, 06:33:43 AM
What make/model of generator? The no load voltage is a little low and may be adjustable depending on what you have. The hz is dependant on engine speed.
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Kohler 12.5kw generator w/Perkins 4.108. I can find the specific model later if needed.
You have photos of your units if they are Cruisairs they can be touchy with starting because of the Freon charge too a photo of the controls will help if they are the Cruisiairs or not lol Cruisairs can be touchy a good unit but very temperamental at times
Quote from: richard5933 on May 27, 2018, 08:16:01 AM
Kohler 12.5kw generator w/Perkins 4.108. I can find the specific model later if needed.
Those generators were used extensively in Wanderlodges and there is a lot of info about them on the Wanderlodge Owners Group board. They are known for producing low voltage as they get older. That can usually be remedied by replacing the voltage regulator ($300). However, there are other maintenance concerns with the unit, including the rear main bearing, brushes and rings. People do the maintenance depending on the size of their pocketbook and level of expertise. A number of people have just replaced the generator head with the new brush-less type from Central Georgia Generator. I have done both and need to fix the one I have now. I'm going with the new had this time. The Perkins is a very durable engine and will run longer than you need it unless abused. The replacement of the gen head will give you a more powerful and reliable generator that will probably outlast the bus.
TOM
Quote from: richard5933 on May 27, 2018, 08:16:01 AMKohler 12.5kw generator w/Perkins 4.108. I can find the specific model later if needed.
Only 107V from a 12.5k generator? Something is *very* wrong there. I'm glad that others have had experience with this unit and are helping.
A few years ago, someone sent me an entire CruiseAir manual, including tech specs, installation, circuit diagrams, etc. I scanned it to emailable files -- if your A/C turns out to be a CruiseAir and you don't have the manual, I'll be glad to send those files to you. Just let me know.
Voltage is being read at the analog meter over the driver. Could be different in the outlets.
We're on the road till Tuesday. My first thought for when we get home is to verify readings and then check connections end to end for anything loose or corroded.
Are the voltage regulators adjustable? If not, anyone have a reliable source?
Quote from: kyle4501 on May 27, 2018, 06:06:43 AM
107 seems low to me,
Low volts allows the unit to pull higher amperage which generates more heat.
that and factor high ambient temp in the bay and then age wear on the compressor and possibly a bad time delay (slug) the inrush start currents at 107v just isn't going to work for two units.
does one or the other function separately ?
good luck.
Quote from: richard5933 on May 27, 2018, 10:24:35 AM
Are the voltage regulators adjustable? If not, anyone have a reliable source?
No. The Wanderlodge board has info on suppliers and maybe a few used ones.
TOM
Quote from: oldmansax on May 28, 2018, 05:05:47 AM
No. The Wanderlodge board has info on suppliers and maybe a few used ones.
TOM
Thinking outside the box here, I wonder if anyone has found available or been able to retrofit an adjustable one? I know they are out there I had one on a generac years ago.
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Typically the voltage regulator will have an adjustment to boost it up a bit. HZ is controlled by engine rpm. I adjust mine so I'm getting 60hz under load which will put the HZ around 63 or so under no load. Good Luck, TomC
Thanks for all the suggestions. Just got home and from a 4-day trip to Black River Falls. Quite a heat wave for us here in Wisconsin as temps approached 100 for a few days.
When we got home and plugged in the basement a/c units did work better, so I'm leaning towards the low-voltage being at least part of the problem. I'll get the meter out tomorrow when it's not so hot and check the performance of the generator (both hz and voltage). A new generator is not in the budget this year, so I'd like to keep this one as long as it does the job at hand. Hopefully I can tweak the settings a bit and make things work.
UPDATE: I just checked the generator output. It's spot on at 60hz and 117 volt at no load. One a/c takes it down to about 112 v and both bring it down to 108 v or so.
The rear a/c will run fine alone on the generator. It will also run fine when the front one is running at the same time. The front unit seems to cycle on and off more often than normal on generator, even more so if both are running at once. With both running on a hot day it cycles off more than on.
My thoughts are this...
Front a/c seems to be struggling more. I will open up the case and check the easy things (poor connections, binding fan, etc). I'll also connect my shore power monitor and see what current each unit draws individually to see if there's a difference.
Generator seems to be putting out the proper hz/volts at no load. Not sure what can be done to help it perform better under load. Suggestions are welcome. In the meantime I will start figuring out how to pay for a new one from Wrico. Not sure if I'll just throw a new head on or try to swing the whole new thing. Lots easier to just change the head, but then I'm stuck with the noise/vibration of the Perkins. Also have no idea when the Perkins will die or if it's being the problem. Since the generator only has two 30-amp breakers on the output legs, I'm thinking that the generator head is the problem.
That's a good generator, Just needs some service and output adjustment. We had 2500 hours on our same unit in the 04. You do need to open the wiring area up and make sure you don't have any overheated connections due to loosening.
Quote from: TomC on May 28, 2018, 12:23:30 PM
Typically the voltage regulator will have an adjustment to boost it up a bit. HZ is controlled by engine rpm. I adjust mine so I'm getting 60hz under load which will put the HZ around 63 or so under no load. Good Luck, TomC
Best to set the hz to be at 60 with full load (both a/c units running plus battery charger) or comprimize by setting it with half load?
I don't see any adjustments on the regulator, but I can tweak the rpm setting to raise both hz and voltage a bit.
Is this unit a electronic regulator circuit board. If so there may be a printed model number for some refference.
Good day
Floyd
Please check your connections at generator, including the head. We found some almost burnt connections earlier in the hours and caught them before serious damage. That issue will cause voltage drop under load. The head should have a removable tin cover on end and box on top has small screws securing it. Yours is painted gold?
From the comments and suggestions I've got the following checklist:
1. Inspect basement a/c unit for free air flow, fan movement, necessary lubrication, obvious mechanical issues, and/or any loose connections
2. Open inspection cover on generator head and check all connections for tight connections and/or other visible issues
3. Confirm tight connections inside generator control box
4. Confirm tight connections at manual transfer switch
5. Set generator engine RPM to produce 120v/60hz operation at load
6. Compare load from front and rear a/c units to be sure that one isn't pulling excessive current
FYI, generator is Kohler 12.5 RCOP67 with an output of only 10kw, not the 12.5 I early thought.
Am I missing anything?
Check condenser and evaporator coils? Make sure no critters have set up their vacation condos. A blast of compressed air should flow through easily with no debris coming out.
Richard,
Have you checked the thermo disk on the compressor. I had a split unit that did what yours is doing. I pulled the disk away from the comp. and let it run for a good while as I needed cold air. I also added enough 22 to let it sweat right up to the comp. Still running like that after 16 yrs
Richard
You should be able to keep that generator running for many more thousands of hours. I had a truck driver friend that his 8kw Powertech had 23,000hrs on is when he sold the truck-with one alternator head replacement from brush type to brushless. Good Luck, TomC
You need a generator person if that Kohler has a 12.5 head a HP setting will make it produce 12.5 K,the problem could the Perkins is at it's limit,it maybe the Perkins is due some TLC and not the head,those tough old generators with a little TLC
I also think you need to have the generator serviced before issues down stream get costly. Have it done by an outfit that knows what they're doing and how to check and or change calibrations. Ask some questions of the establishment. There are good outfits out there, just have to search them out. Maybe an old outfit that is familiar with your unit and not going to try to make a sale on a replacement.
I don't have the manual for the exact generator setup I have. The manuals I have are for various close setups but not exact. So, I am working with questionable data.
What I've found is that the model number ending in 67 is set at 10.3kw instead of 12kw with a note stating "adjusted for radiator fan"
Not sure what's going on or why this is so. My set up uses a remote radiator and a remote squirrel fan to cool the generator.
If it's possible to reconfigure the generator to put out 12kw I'd love to find out what's involved.
Yep the engine driven fan robs HP so the KW drops with your setup you are probably at 12 kw
Best thing about these new smart phones is you can turn the flash on and reach in and take all kinds of pictures.
Great for tough viewing situations
good day
Floyd
UPDATE:
After doing lots of research and talking to the guy that services our home's a/c units, here's what I've done...
I opened both basement a/c units and did a visual inspection. Fan motors turned freely, and all wire connections were clean and tight. There is no visible damage or leaks anywhere. Used compressed air to blow the condensing coils - both were relatively clean and now even cleaner. The relay contacts were contained inside a plastic housing that didn't seem keen on being opened, so I left it alone. The interior units are really quite clean and all connections were tight.
All connections at the generator and at the transfer switch were checked. All were tight. No signs of overheating in sight.
I did open the inspection cover at the end of the generator head. The three rings were in great shape and the brushes as well. Connections were tight as far as I could tell.
Finally, I adjusted the governor on the generator to raise the voltage & hz just a tad. At no load it produces 120v @ 61hz. At moderate-to-full load it read 115-117 volts @ 60hz. Previous readings at load were just under 110 volts and 57-58 hz. A manual for a similar system shows low voltage as a cause of short cycling, so hopefully this was the issue.
The a/c units both ran fine today. Both units blow cold and no short cycling yet. Fingers crossed. Of course, the outside temps are not that bad and only in the upper 70s. I'll be able to better test things in the coming days as the temps are expected to be in the 90s.
We're heading to Gillette WY next month for a week and plan on dry camping three nights on the way, so we'll have a chance to test it out more thoroughly then as well.
A replacement generator is on the list for next year, once we figure out the best approach. I think that a 13kw Wrico unit with remote radiator should be able to sit right on the existing slide, although the mounting feet may need moving. But, this is a project for down the road.
If you think of something I've missed, please let me know.
And now I believe we have the final diagnosis...
The unit runs pretty well, both on shore power and on generator. However, when the temps get high (95+) the unit short cycles. It will run for anywhere from 5-15 minutes and then the low pressure switch shuts off the compressor. We had an HVAC guy come out today and diagnose the unit, and his conclusion is that it's low on refrigerant. Probably has a leak, or possibly it was not filled properly the last time it was serviced (no idea when that was). The problem now is that it is using r12. According to him there is no r12 available in this area. Don't know if it's true or not, but he was unable to do anything. Suggestion was made to have the unit converted to r134, which of course is not something his company does.
It took me weeks to find a guy willing to come out just to diagnose the problem. Now I've got to decide if it's worth moving forward with trying to find someone else to do the repair. The guy that came today said that the unit is much more like a split system found on a convenience store cooler than a mini-split or residential unit. He thought that I might be able to find a commercial refrigeration guy to do the repairs.
The other option is to abandon hopes of having a clean roof and just install the roof a/c in the forward roof vent opening. I really want to keep the bus looking like a bus and putting a roof a/c on top is not at all what we want, but it might be the most practical solution. Of course, I'm not one to choose practical.
I was wondering if any of the relays are visible, and possibly in the commercial size. Meaning do they or any have removeable covers. If so with the electric turned off for that system inspecting the relay for visible issues, like loose wires and or burnt contact points.
Good day there
Floyd
The tech that was here today put his gauges on the system. He was able to verify that the problem is with low refrigerant. Under mild weather conditions (75-80 degrees) it runs slightly low pressure on the low-pressure side. As the ambient temp increases and the unit works harder the low-pressure sides keeps dropping slowly until the low-pressure cutoff switch shuts things down. Once the pressure equalizes it will run again for a while, and then the pressure drops...
Doesn't seem like the problem is with the relays or low-pressure switch itself.
I've found a small commercial refrigeration outfit in town that seems willing to come take a look next week. We'll see if they are able to follow through. Maybe they can find the leak (if there is one) and get their hands on some r12 to top it off.
Are the caps on the pressure check ports ? I have seen those (the valves in side) work under pressure rise and fall leak ever so slowly...
I would definitely go where I could get some R-12....
The system must be ancient, are you sure it isn't R-22 ?
wonder if this works...https://www.ebay.com/i/122508929925?chn=ps
Quote from: eagle19952 on July 06, 2018, 10:46:17 AM
Are the caps on the pressure check ports ? I have seen those (the valves in side) work under pressure rise and fall leak ever so slowly...
I would definitely go where I could get some R-12....
The system must be ancient, are you sure it isn't R-22 ?
wonder if this works...https://www.ebay.com/i/122508929925?chn=ps
Am I sure it's not r22? No.
The tech hooked up his gauges, and based on the pressure settings his best guess is that it's got r12. He also based that on the low-pressure differential switch. All this means nothing to me, so I'm going based on what he said. A photo of the switch is attached - if someone can help me identify the type of refrigerant it would be helpful.
Is there a way to tell for certain? There are no visible labels or markings on the unit.
Here's a photo of the compressor ID plate as well as the overall condensing unit. From what I can find in the online Copeland information, it's likely r12. Not the best news, since that most likely means that it would have to be switched to r134, if that's even possible. I'm working with a guy that hopefully can come to look next week. Of course, every a/c tech immediately yells about how busy they are, so it's hard to get one to come out right now.
Model number on the compressor is: KAJ3-0100-CAA-
What's most impressive is that it looks like they still make the thing, after 44 years. Actually, most impressive is that it blows cold still, at least till the pressure drops.
Richard, it's very easy to tell if it's R12 or R22. I worked on a lot of unknown equipment when I owned a commercial refrigeration business.
The only caveat is the bus MUST be the same temperature inside and out. I would open bus windows and turn on all AC systems to FAN ONLY for a few hours before I test. After temperature has equalized inside and out, (meaning the temp of the inside evaporators and outside compressors/condensers/piping are all the same) attach gauges to the system and check the pressure. That will tell you the kind of refrigerant. for example, R22 @ 70F = 121.5 PSI. R12 @ 70F = 70.2 PSI. As you can see, that is a vast difference. You can Google "R22 PT chart" and "R12 PT chart" for charts with all the temps listed.
FYI, most CruiseAir systems of that era used R22, which any HVAC company should have. I betting yours did too.
TOM
Richard
I should have added one thing. If that system use R22, it should be charged to 15F superheat. R12 should be 10F superheat. If your HVAC guy appears confused, get another guy. Again, I'm pretty sure you have an R22 system.
TOM
Quote from: oldmansax on July 07, 2018, 04:52:05 AM
Richard
I should have added one thing. If that system use R22, it should be charged to 15F superheat. R12 should be 10F superheat. If your HVAC guy appears confused, get another guy. Again, I'm pretty sure you have an R22 system.
TOM
Thanks Tom for the info. I did find another guy to look at the system - this one is from the world of commercial refrigeration. From what I've been able to determine, the system we have is NOT a Cruisair unit at all. It looks like Custom Coach used condensing units originally designed for use in commercial applications, like coolers and such. The new HVAC guy is coming Tuesday. His information (based on the compressor & condensing unit) shows that we've got r12. When I researched on the Copeland site I found the same. He'll verify when he comes out.
I hope that he finds it's really r22, as that's still easily available. If it is r12 I hope that he can find the leak, fix it, and then find some r12 to refill the system. Lots easier and much less expensive than trying to change refrigerant. I'll update after he comes Tuesday.
Today the guy came out to look at the system. Just the kind of HVAC guy I needed too - he works on his own in his own company, and he has experience with both residential and commercial systems.
Seems that what Custom Coach did was use a commercial split system, just like you'd find cooling a large walk-in cooler, to cool the bus. Actually, two of them. The condensing units in the bays use heavy-duty 115v compressors, which he says are work horse compressors and should last years more.
The front system that was shutting down after a while was somewhat of a mystery. Some of the pressure/temps were spot on, others not so much. The one that worried him was actually the high pressure, and his suspicion was that the compressor was shutting down when the compressor reached it's internal high pressure/temp safety shut off point. The system was supposed to have r12 in it as refrigerant, but the pressures (especially the high pressure) were not correct. He tried to evacuate some of the refrigerant to see if there was too much. Didn't help. Then he evacuated the system, blew it out with nitrogen, evacuated again, changed the dryer/filter, and refilled with an r12 replacement that is supposed to be compatible with the oil in the system. His hunch was that there was a "non-compressible" in the system - either air or some other contaminant introduced by someone working on the system in the past. Presence of something like this would act to essentially downgrade the effectiveness of the condensing coil and raise the high pressure.
After the work he did, the system has been running with no problems so far. It's making cold (very cold) air and cycling on/off with the thermostat as it should.
While he was here, he checked the rear unit. It had bubbles in the sight glass so he topped off the refrigerant. Looks like we might have a very slight leak there, but not one that could be confirmed today.
We're going to run the systems on our trip over the next few weeks and see how things go. Good news is that the repair guy says that all the parts are still around, more than we'd need to totally rebuild the system if necessary. He was actually impressed with the quality of parts Custom Coach used to build the system.
That's all for now.
Quote from: richard5933 on July 10, 2018, 11:14:21 AM... Good news is that the repair guy says that all the parts are still around, more than we'd need to totally rebuild the system if necessary. He was actually impressed with the quality of parts Custom Coach used to build the system.
That's all for now.
Sorry you've had problems with a major system, but -- if you have a problem -- this is about as good news as you can get. Good luck from here on out.
always nice to find A GUY that knows what he is doing and is in your back yard
Quote from: sledhead on July 10, 2018, 03:47:23 PM
always nice to find A GUY that knows what he is doing and is in your back yard
Actually, his company name is: The Cool Guys
So yes, I found a guy. :)