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Old 06-14-2016, 06:31 PM   #231
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lots of heat loss when converting a window unit but then i make custom Air units all the time so go for it if you know the thermodynamics and how to get it to work right...

I agree most RV units are Junk!! my neighbor had a camper and I swear every year i had to go work on his Junk dometic rooftop air units....

and of course im sure everyone taking road trips has seen the shrouds laying along side the freeway that have blown off of rooftop units...

to build my own A/C I would sooner start with a PTAC than I would a window shaker... just because most of the mare 2 shaft 2 motor and some are even ductable...

Minisplits are great other than the massive outdoor unit size... hard to basement mount.. the indoor units on those are easy to take apart and modify.. (thats what I built my house A/C based on.. before VRV was even thought of for residential)..

-Christopher
Alright caddie
Give me your thoughts on this one? I have been told that these units are screwed and can't be sold.
I still have access to 7 PTAC's that were special ordered from TRANE and yes I have talked to some of them and get the same answer cause I want to change them.
They were built for a job that spec'd 418? Not 408 or 460v
Ended up the corp of engineers couldn't provide that voltage either so all of the equipment for mechanical and elec. changed to 460 so my old company stored everything because TRANE didn't want them back.
I wanted a PTAC for my build?
Is it worth the money to convert one or two? Is it cheaper to find the correct voltage?
What would need to change? I know step down/up transformers are high dollar but what about changing compressors and capacitors for the proper voltage?
I can get 7 of them for almost nothing but don't know if/how to make them usable for us.?
Thanks for any ideas.
Or just tell me it ain't worth it?
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Old 06-14-2016, 06:44 PM   #232
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wow ive never heard of 418 volts.. Ive heard of 480 3 phase.. but wow thats really unusual for PTACs to be made that way.. most of the ones ive seen even in major hotels that we work on are standard 240.. OCCASIONALLY ive seen a 277 go in..

im assuming the compressor and fan motors are all SPEC's for this voltage? (if you look at individual parts they may have voltages listed on them.. sometimes motors can be rewired for different voltages).. the circuit boards undoubtedlty run on a power supply transformer that most likely either provides standard 24 VAC to the input of the board or may have jumpers which set the voltage for the board itself...

are these single shaft or dual shaft units? (one motor or two running the indoor and outdoor fans?)..

-Christopher
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Old 06-14-2016, 07:04 PM   #233
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They are two motor with single shaft each and everything that i can remember was wired/compatabile with the crazy voltage to save room?
If you had a 460 unit? Could/would you spend the money to change it?
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Old 06-14-2016, 07:30 PM   #234
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the problem is the compressor... at a minimum that PTAC likely was designed to run on 240 so your generator would have to output 240 to run even a standard PTAC.. (disconect the heater because 5kw heat would crack up most gennies).. 240 volt fan motors are everywhere and easy to change but if the compressor is designed on that wierd voltage and is not alterable that makes things worse.. like I say some motors have different combintions of wires to use for different voltages... id take the covers off of one and look up the numbrs on the motors and see if they are universals or not as a start..

-Christopher
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Old 07-06-2016, 03:09 PM   #235
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JUST got word, wife's retirement check will be here via FedEx on Friday!!!! WoHOO!!!!!!! Serious building will commence directly thereafter!!!!!!

M
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Old 07-06-2016, 03:19 PM   #236
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JUST got word, wife's retirement check will be here via FedEx on Friday!!!! WoHOO!!!!!!! Serious building will commence directly thereafter!!!!!!

M
Congrats. It's a good feeling to get back money that we've worked so hard for in our lives. I'll get my first SS check in November, and looking forward to it.
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Old 07-09-2016, 10:31 AM   #237
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WE HAVE IT!!!!! Now to start ordering up parts!!! WoHOO!!!!!!
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Old 07-09-2016, 07:41 PM   #238
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WE HAVE IT!!!!! Now to start ordering up parts!!! WoHOO!!!!!!
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Old 07-10-2016, 05:46 PM   #239
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Ok, one *perhaps* stupid question, anyone know what the height of an 11R22.5 tire and a 12R22.5 tire should be and what the differences in height are?

I'm trying to see if I can bump up the top end while keeping the engine turning @ 2K rpm. Preferably getting Heavy to get up to 65 mph by changing tire size. So far with the help of Tango's calculator I have figured going from 11R22.5 to 12R22.5 gets me close to 60 mph from 48 mph. Yes, a big jump, but not quite big enough. The question is am I using the right calculations such as tire height and (I believe) the 643 tranny having a 1:1 final ratio going to the drive shaft. I do know I have a 5.29 gear ratio in the rear axle, but the rest I can use a little bit of help on to be sure I can get 65 mph @ 2K rpm with 12R22.5 tires. Just trying to save some $$$$ before spending any........

Thanks all!!!!

M1031
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Old 07-10-2016, 07:26 PM   #240
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Ok, one *perhaps* stupid question, anyone know what the height of an 11R22.5 tire and a 12R22.5 tire should be and what the differences in height are?
I just looked that stuff up the other day when I found out that the prison bus I'm looking at had 12's on it. I hadn't heard of 12R22.5 up until that time.

I can't find my way back to the original chart; the Internet is not good with bread crumbs like that. But my memory is that the difference is not much; 11R's were 41.5" diameter vs 12R's at 42.5 or numbers close to that.

At least, I can tell you that the info is out there and you can Google it up, even if I can't.
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