Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > MOTORHOME FORUMS > Class A Motorhome Discussions
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 06-18-2019, 05:43 PM   #15
Senior Member
 
Frutza's Avatar
 
Join Date: Dec 2011
Location: Corinth, MS
Posts: 485
Quote:
Originally Posted by Gary RVRoamer View Post
Better idea: Buy a decent quality brand of cap on Amazon or Ebay and install them immediately. Keep the old ones as spares.


Why? The old caps are aging and will fail eventually, so get those new ones installed and postpone the inevitable. Better to avoid the failure altogether than to merely have a spare when the a/c quits at 11 pm. If you ever have to use the old spare, get a new one to replace it at your convenience.
Good advice, that's what I did
__________________
Mike & Becky
2005 Holiday Rambler Navigator 45PBQ
Frutza is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 06-19-2019, 08:04 AM   #16
Senior Member
 
153stars's Avatar
 
Join Date: Mar 2019
Location: Braidwood Il.
Posts: 8,300
The start cap is like a jump start,dumps it stored energy to get compressor moving. The run caps help sync the power demand amps with the less volts available at the paticular part 60hz phase .These two are partially out of phase with each other. The run cap smooths it out"lines them up better" as seen with amp/volts phases on an oscilloscope you can hear the difference and measure reduced amp draw on a meter. Too big run cap will push the sync the other way past idea sync. Think of timing on a gas engine the right amount of advance timing is ideal.A multi cap can be replaced wit two caps instead if you can fit them in you may just need a jumper wire.
__________________
95 Monaco Crown Royale
M11 400hp, 4060 trans.
Aquahot, Generac Guardian7.5k
153stars is offline   Reply With Quote
Old 06-19-2019, 10:07 AM   #17
Senior Member
 
tropical36's Avatar
 
American Coach Owners Club
Join Date: Jul 2007
Location: SW Florida
Posts: 2,971
Quote:
Originally Posted by Ancabuild View Post
As I was traveling in Florida, my roof ac in the front of the coach quit working and trip the breaker, I did some troubleshooting once I got to my next destination and found out the starting capacitor was fried. I went looking for one and when I found it I also found that the price was extremely expensive at $52.00 at one rv place when I could buy it on amazon for $12.00, of course I need it right then. So, I had to fork their asking price. So, If you own an RV I would advise you to find out which capacitors you need for start and run capacitors for your ac's and purchase a spare one of each and have them with you to replace on Amazon so that you don’t get stabbed like I did. Hope this helps someone. Cheers
Ahhhhhh, could you not wait, one or two days and pay a little extra for the quick shipping option?
Last one I bought, was from a dealer as well and for approx. $26, which was still a lot more than Amazon.
__________________
07 Revolution LE 40E_1 1/2 Baths_Spartan MM Chassis_06 400HP C9 CAT_ Allison 3000
Dinghy_2010 Jeep Wrangler JKU ISLANDER
1998 36ft. National Tropi-Cal Chevy Model 6350 (SOLD)
tropical36 is offline   Reply With Quote
Old 06-19-2019, 10:25 AM   #18
Senior Member
 
Join Date: Jul 2018
Posts: 4,873
Quote:
Originally Posted by TriMoot View Post
Thanks Solo_RV_Guy. I went home at lunch and squinted into the air vents and came up with these numbers. It appears the front and back AC units are both the same part number, just different serial numbers.

I went over to Dometic's site and attempted to plug in the numbers somewhere but didn't have much luck. I sent them an email with the info in hopes they will get back to me.

But just in case you have a different website, here's the numbers:

Front: Part# 3105457, Box Kit, S/N: 63508383

Rear: Part# 3105457, Box Kit, S/N: 6350373 (I'm thinking the serial is wrong as I was really squinting hard to see it. I even recorded my voice saying the numbers, but I think I crossed my eyes or something as I would think they would be closer in number. Maybe the 8 is missing after the zero.)

Thanks again!

The part number is for what Dometic calls "mechanical air distribution box." You need the model number from the A.C. chassis. You'll probably have to get up on the roof and remove the shroud and if you're up there, just look for the capacitor(s). Depending on the exact model you *may* have both a "start" cap and a "run" cap. The start capacitor is likely physically larger.


If you need to remover the capacitor to read the numbers on it, be very careful to not touch the terminals on it. You can discharge it by shorting the terminals together with a screwdriver shaft for a couple of seconds and it will be safer to handle.


Dometic has redesigned their site; it used to be much easier to find replacement part info. (Grrrrr.)
__________________
2005 Four Winds Majestic 23A
“To the world you may be one person; but to one person you may be the world.” - Dr Suess
Solo_RV_Guy is offline   Reply With Quote
Old 06-19-2019, 01:34 PM   #19
Senior Member
 
Monaco Owners Club
Join Date: Sep 2013
Posts: 2,476
I generally use MARS capacitors. https://www.marsdelivers.com/products/94/Capacitors/
__________________
2014 Newell 2020P 45'8" ISX 600 HP
hypoxia is online now   Reply With Quote
Old 06-19-2019, 01:40 PM   #20
Dom
Senior Member
 
Join Date: Apr 2018
Posts: 672
Quote:
Originally Posted by Ancabuild View Post
The easiest way is to match the numbers on the existing caps by getting up there and reading or taking a picture of the specs. The guy that sold the cap to me said you can go a little larger capacity but not smaller
This is only for the start capacitor (black) the run capacitors must be within 5%-+Having said that run capacitors are also rated with voltages. You can go with a higher voltage rating but not capacitance
Dom is offline   Reply With Quote
Old 06-19-2019, 03:15 PM   #21
Senior Member
 
Join Date: May 2017
Posts: 1,299
I don't know about RV A/C units but many home A/C units have 2 capacitors, a start and a run. You can often buy brand name, direct replacement for 20%-30% of the price on eBay. Worth having around.
__________________
Retired. 31 year of automotive engineering for one of the Detroit 3, specializing in Powertrain Control Systems.
theoldwizard is offline   Reply With Quote
Old 06-19-2019, 04:24 PM   #22
Senior Member
 
Join Date: May 2015
Posts: 127
As some others have mentioned here and on other forums, rarely, probably never do you see a start capacitor on a fan, only on a compressor. That will always be a single unit. On the other hand, fan and compressor both use a run capacitor, often a combination unit that handles both the fan and the compressor. These have 3 terminals labeled fan, common, and herm (herm being the compressor). I agree with those who question the quality of many Chinese capacitors simply because I see so many other Chinese imports that are so sketchy! FWIW, the kinds of capacitors we’re talking about here are constructed by laying a separator between two conductors. The separator is a dielectric (paste or plastic that I have seen) and the conductors look like foil. These pieces of foil are very close to each other because this separator is super thin. The capacitance depends on the thickness of the separation between the conductors and the area of the conductors. This conductor/dielectric/conductor assembly is rolled up and put in the “can” we call the capacitor. Having said all that......whew......it doesn’t take much for a power surge or an internal physical contact between the foils to cause the whole thing to fail. Seems like a very common thing and so spares make sense.
pbpaul is offline   Reply With Quote
Old 06-19-2019, 04:59 PM   #23
Senior Member
 
TriMoot's Avatar
 
Join Date: Oct 2013
Location: Melbourne Beach, FL
Posts: 1,945
Blog Entries: 2
Quote:
Originally Posted by Solo_RV_Guy View Post
The part number is for what Dometic calls "mechanical air distribution box." You need the model number from the A.C. chassis. You'll probably have to get up on the roof and remove the shroud and if you're up there, just look for the capacitor(s). Depending on the exact model you *may* have both a "start" cap and a "run" cap. The start capacitor is likely physically larger.


If you need to remover the capacitor to read the numbers on it, be very careful to not touch the terminals on it. You can discharge it by shorting the terminals together with a screwdriver shaft for a couple of seconds and it will be safer to handle.


Dometic has redesigned their site; it used to be much easier to find replacement part info. (Grrrrr.)

Thanks Solo: Yeah, I had also emailed Dometic and they told me the same thing..wrong numbers. So I'll hopefully have some time this weekend to crawl up there and check them out.

Thanks for the reminder to discharge the caps 1st. I'd hate to remember it after I wake up from falling off the roof..OUCH!

I really think it's a great idea to get a jump on this and have them ready for when (not if) it fails.

Thanks to all for another great thread.
__________________
___________________
2005 Newmar Essex 4502
1997 Suzuki Sidekick JX, Spokane, WA (Hoping to replace this soon)
1997 RexAir 32' Ford F53 Chassis, Banks system.
TriMoot is offline   Reply With Quote
Old 06-19-2019, 06:13 PM   #24
Senior Member
 
Barneyb's Avatar
 
Fleetwood Owners Club
Freightliner Owners Club
Join Date: Jan 2019
Location: Wadsworth, Ohio
Posts: 379
Quote:
Originally Posted by TriMoot View Post
So how do we determine exactly which caps we need? Off the top of my head I don't know what model of AC units I have other than Dometic, and since the rig is from 1997 I am assuming the units are too. Guess I should crawl up there and grab the existing part numbers from the caps just to be safe. Hopefully they're easy to see and read part numbers.
Remember capacitors store energy, be very careful when looking for numbers, It can be a “Shocking” experience
__________________
Barney & Penny with our two puppies Lucy & Dixie
2008 Fleetwood Discovery
2020 Jeep Cherokee Trailhawk
Barneyb is offline   Reply With Quote
Old 06-19-2019, 06:21 PM   #25
Dom
Senior Member
 
Join Date: Apr 2018
Posts: 672
You could take the capacitor to a motor rewind shop, and if it is still functioning there is a meter that can tell the capacitance. I'm sure they would be happy to do that. I have one, but its a bit of a trip for you
Dom is offline   Reply With Quote
Old 06-19-2019, 07:06 PM   #26
Senior Member
 
chuckftboy's Avatar
 
Winnebago Owners Club
Fleetwood Owners Club
Holiday Rambler Owners Club
Join Date: Dec 2011
Location: North East Florida
Posts: 2,007
I will chime in about capacitor quality something I know since I've been in the A/C industry quite awhile
From the early 70's until mid 80's capacitors were generally made in the U.S. and seldom failed. Mid 80s' until late 90's our capacitors came from Mexico and they seamed to last 5 to 7 years. Since then all the manufactures use Chinese caps and they seem to last around 18 months.
Now we as a business sell AmRad capacitors. built in the U.S. as replacements and have been doing so for a long time with no failures.
__________________
2019 Horizon 42Q
Cummins L-9 450 HP
Maxum Chassis / IFS with Tag
chuckftboy is offline   Reply With Quote
Old 06-20-2019, 01:22 AM   #27
Senior Member
 
Ancabuild's Avatar
 
Join Date: Aug 2011
Location: Woodstock, GA
Posts: 182
Quote:
Originally Posted by tropical36 View Post
Ahhhhhh, could you not wait, one or two days and pay a little extra for the quick shipping option?

Last one I bought, was from a dealer as well and for approx. $26, which was still a lot more than Amazon.


It was more than a couple of days and with 90 deg. weather, two grands, a daughter and DW I could not put it off. I would have forked more than money to keep them at peace. If you know what I mean.
Ancabuild is offline   Reply With Quote
Old 06-20-2019, 04:24 AM   #28
Senior Member
 
Monaco Owners Club
Join Date: Feb 2016
Posts: 1,051
Quote:
Originally Posted by Ancabuild View Post
It was more than a couple of days and with 90 deg. weather, two grands, a daughter and DW I could not put it off. I would have forked more than money to keep them at peace. If you know what I mean.
No doubt just about anyone else would have done the same including me.
BigLar368 is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Hard start capacitors stormrider15 RV Systems & Appliances 11 10-17-2017 01:27 AM
Replacing all 3 capacitors on A/C units marjoa RV Systems & Appliances 16 06-29-2017 10:16 AM
Discharge capacitors on out-of-the -box airconditioner? adamfolger Monaco Owner's Forum 3 04-18-2016 10:00 PM
Coleman Air Conditioner Capacitors ko4nrbs Winnebago Industries Owner's Forum 1 01-08-2014 10:53 AM
Basement AC Questions..motor capacitors smlranger Winnebago Industries Owner's Forum 22 06-12-2011 03:47 PM

» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 08:12 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.