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grantb4 · 08-19-2007, 12:44 PM

OK, I think I may have found the part number from the file 3309305.005.pdf:

24 Compressor Start Kit 3106732.013

I'm in Orange County, CA and would love to get my hands on one ASAP.

HowieE · 08-19-2007, 12:46 PM

Considering the cost of replaceing or repairing an AC I would suggest that one never leave hone without a voltmeter permently mounted in thier trailer. $30.00 or $40.00 for a plugin voltmeter is a cheap insurance. I always look at the voltmeter before turning on the AC and then again as soon as the compressor kicks in to insure there was not a harmfull voltage drop when the AC load was applied.

I have seen so called 30 amp campsites that were in fact feed by less than a number 10 wire, 30 amp capisity, and conneted to 5 or 6 sites off that number 10 wire. If any 2 of the campers had turned on thier AC the whole system would have gone down.

tlavergne · 08-19-2007, 01:11 PM

Has anyone ever used one of these?
Progressive Industries is committed to making the RV experience easier
It monitors the incoming power into the trailer and kicks off the power if there is no ground, wired backwards, or the voltage falls below 104 or goes over 132.
Looks like it could save a lot of headaches and money.
Tom

lewster · 08-19-2007, 06:53 PM

grantb4,

The part # for your upper unit in located above the metal box that you show in your photo. The number on the metal electrical box is just for that part, not for the upper unit that sits on top of your roof.

Take a flashlight and look above the box, and you should see a model#, serial# and product # as all Dometics have these.

You need a hard start kit, part # 3106732005 which includes the PTCR (your burnt out little black part) and a new start cap. The PTCR clips onto the start cap and is then wired into the circuit. There is a diagram inside the cover that you removed to get access to the caps.

Also, there should be a length of perforated metal banding (commonly called 'plumbers tape') that holds the caps in place with 2 hex head sheet metal screws. From your description of the wiring, it does not seem to be correct, but I don't have a wiring diagram in front of me as I write this. When you re-connect the wires, be sure to follow the wiring diagram that is on the access door, and double check the wiring. I have seen new units come from Dometic that were improperly wired.

You should be able to get the kit from any well stocked RV dealer or parts supplier.....also from Camping World.

I would not use any non-Dometic replacement unless the specs were identical! Close doesn't cut it here....

Quote:

Originally Posted by grantb4

I have another couple of questions. Ours blew last night and I'm just getting to the laptop now. Where should the starter cap be fastened? In our unit it was floating loose!

This is not the first time something like this has happened to us. Our fridge was not plugged into A.C. and the fridge flue top/cap thingy was floating around the fridge compartment.

So more about our cap... I've attached some more crummy pics. Can someone give me the correct part number and where to buy? I looked at dometicusa.com and some of the start caps are different. It looks to me that the PTCR was attached directly to the cap, and a red wire to that. Also a white wire attached to the other post of the SAME terminal. Finally a black wire to the OTHER terminal. See the photos. The cap says this on it:

43-52MFD 250VAC. So maybe 50-ish ufd at 250v?

And upon closer inspection the PTCR does come off (what's left of it). The PTCR says this:

WSX-7 A-1 Components motor starter

I think the air conditioner is 630515.331 according to the warranty docs that came with the trailer. We did not get a manual for this unit in paper form.

grantb4 · 08-19-2007, 09:40 PM

Quote:

Originally Posted by lewster

Also, there should be a length of perforated metal banding (commonly called 'plumbers tape') that holds the caps in place with 2 hex head sheet metal screws. From your description of the wiring, it does not seem to be correct, but I don't have a wiring diagram in front of me as I write this. When you re-connect the wires, be sure to follow the wiring diagram that is on the access door, and double check the wiring. I have seen new units come from Dometic that were improperly wired.

Thanks for your help. I will be calling around tomorrow.

No banding/strapping at all! I think my trailer was built at about 4pm on a Friday! I agree the wiring diagram does not match my description. What I saw was black wire on one terminal post. White wire on the other. Also on the one with the white wire was the PTCR directly attached and then a red wire attached to the PTCR. You can kind of make it out in one of my photos above. Also you can see the wiring diagram in one of my photos and it matches the one attached -- the diagram on the right. The wiring was totally wrong compared to that! I don't know if the cap is polarized or not, the top was kind of melted down. My model number is 630515.331.

lewster · 08-19-2007, 10:09 PM

Quote:

Originally Posted by grantb4

Thanks for your help. I will be calling around tomorrow.

No banding/strapping at all! I think my trailer was built at about 4pm on a Friday! I agree the wiring diagram does not match my description. What I saw was black wire on one terminal post. White wire on the other. Also on the one with the white wire was the PTCR directly attached and then a red wire attached to the PTCR. You can kind of make it out in one of my photos above. Also you can see the wiring diagram in one of my photos and it matches the one attached -- the diagram on the right. The wiring was totally wrong compared to that! I don't know if the cap is polarized or not, the top was kind of melted down. My model number is 630515.331.

The schematic on the right is correct. Your unit supercedes these, but the wiring is the same. If you look at the start cap, you place the PTCR on one terminal (it shouldn't be polarized) with the red wire from the top of the PTCR going to the run cap herm (compressor) terminal along with the other red wire from the compressor.

The white wire (ground) goes on the other start cap terminal and terminates in the center stud of the run cap (common terminal). The black wire is for the reversing valve and is on the same start cap terminal as the common white wire, NOT the terminal with the PTCR.

This is only correct if you have a heat pump! There should be a diagram similar to this on the cover of the capacitor housing. I would definitely check that to be sure that you indeed have the black wire going from the start cap to the reversing valve. Mis-wiring will cause premature PTCR and start cap failure, and is more than likely what happened to yours.

grantb4 · 08-20-2007, 07:15 AM

Quote:

Originally Posted by lewster

This is only correct if you have a heat pump! There should be a diagram similar to this on the cover of the capacitor housing. I would definitely check that to be sure that you indeed have the black wire going from the start cap to the reversing valve. Mis-wiring will cause premature PTCR and start cap failure, and is more than likely what happened to yours.

Yes we have a heat pump. I took a photo of the diagram on the "lid" of the control box (2 screws, 2 tabs), see way above. It's almost identical the the one on the right of the later PDF JPG. The main difference I see is that in my case the PTCR is shown as if it was part of the capacitor, rather than a separate component. There is/was no capacitor housing, just the metal around the control board area which housed the two caps too. I'm curious to see if there is any mounting hardware to be found for my floating start cap, now that I know what was supposed to be there. I'm also surprised with such mis-wiring that there wasn't more mess and much earlier. We've had the thing two years. I think I'll stand waaay back when I fire it up next time, considering the wiring will be different. Scarey.

SilverCabin · 08-20-2007, 09:35 AM

Quote:

Originally Posted by HowieE

I always look at the voltmeter before turning on the AC and then again as soon as the compressor kicks in to insure there was not a harmfull voltage drop when the AC load was applied.

I've attached this snip from HowieE's post above. Questions: If you see a huge voltage drop when the compressor comes on, and quickly turn off the unit, is it still okay? How many of these hits can it take becore toasting the capacitors?

Thanks,

Randy

grantb4 · 08-23-2007, 07:11 PM

Today I had a chance to replace the start capacitor and PCTR. Dometic USA has a part that was suitable and I had it in my hands within 2 days for a total cost of about $30 including shipping. Part number: 3106732.013 I think this part is probably a little old school (PCTR looks more mechanical than the one that exploded). The person on the phone was nice, but not technically knowledgeable.

So the first photo just shows the inside wiring. It's not relevant to the repair, but I wondered if anyone knew what the two unterminated connectors are for? (Circled in red)

The second photo shows the schematic on the control box lid.

The third photo shows the internal of the control box, but without the start cap and pctr which I had removed last weekend.

In the next photo I have lifted the box out of it's normal lowered position in order to get access to the cramped area where the start cap goes.

The final photo shows the new start cap installed and hopefully wired properly (unliked the factory wiring). Basically the red wire on the non-cap side of the pctr goes to the other red wired at the run cap, the white and black wires are connected on the other terminal of the cap (the white wire goes where the other white wires go on the run cap, I can't remember where the black one went but I think it was longer and travelled quite a distance).

Also note the complete absence of any support hardware! The screw that holds the pctr to the sheet metal keeps the cap in place, but there has to be something else that's missing from my unit. I would love a picture of the correct installation. There is a screw near the bottom of the cap that does nothing, so that's probably where the proper mounting hardware goes.

HowieE · 08-24-2007, 07:48 AM

Quote:

Originally Posted by SilverCabin

I've attached this snip from HowieE's post above. Questions: If you see a huge voltage drop when the compressor comes on, and quickly turn off the unit, is it still okay? How many of these hits can it take becore toasting the capacitors?

The voltmeter is mainly to check a campground voltage before you start using things, AC, or Heaters, in the trailer. Low voltage will cause damage to the compressor over time, running time on a give day, because of increased heat. As voltage to a motor goes down internial heat will go up. The older Airstream AC units had an indicater light on the control panel that lite when the voltage was low.

I would prefer not to use the AC under low voltage conditions, -105 volts. Yes the hard start kit will help start the unit but the unit life may be effected. With a meter it becomes a judgement call reather than a crap shot.

lewster · 08-24-2007, 08:46 AM

Quote:

Originally Posted by grantb4

Today I had a chance to replace the start capacitor and PCTR. Dometic USA has a part that was suitable and I had it in my hands within 2 days for a total cost of about $30 including shipping. Part number: 3106732.013 I think this part is probably a little old school (PCTR looks more mechanical than the one that exploded). The person on the phone was nice, but not technically knowledgeable.

So the first photo just shows the inside wiring. It's not relevant to the repair, but I wondered if anyone knew what the two unterminated connectors are for? (Circled in red)

The second photo shows the schematic on the control box lid.

The third photo shows the internal of the control box, but without the start cap and pctr which I had removed last weekend.

In the next photo I have lifted the box out of it's normal lowered position in order to get access to the cramped area where the start cap goes.

The final photo shows the new start cap installed and hopefully wired properly (unliked the factory wiring). Basically the red wire on the non-cap side of the pctr goes to the other red wired at the run cap, the white and black wires are connected on the other terminal of the cap (the white wire goes where the other white wires go on the run cap, I can't remember where the black one went but I think it was longer and travelled quite a distance).

Also note the complete absence of any support hardware! The screw that holds the pctr to the sheet metal keeps the cap in place, but there has to be something else that's missing from my unit. I would love a picture of the correct installation. There is a screw near the bottom of the cap that does nothing, so that's probably where the proper mounting hardware goes.

grantb4,

Actually, your start cap gets placed right beside the run cap and BOTH of them go under the plumbers tape to secure them. Use a longer piece if necessary and be sure that the bottoms of both are at the 'floor' level of the control box.

That black wire that is found on the other terminal at the start cap with the white one should be going to the reversing valve of your heat pump. It is a little 3-way vave with 3 copper tubes coming to it and should have a couple of wires from it also, one of them being the black one to the start cap.

grantb4 · 08-24-2007, 09:03 AM

Quote:

Originally Posted by lewster

Actually, your start cap gets placed right beside the run cap and BOTH of them go under the plumbers tape to secure them. Use a longer piece if necessary and be sure that the bottoms of both are at the 'floor' level of the control box.

I don't think there is room to do it that way, but I'll look again. You can see that the run cap is not at the bottom of the box. I'd love to see someone else's new Airstream and how theirs was done. It's not a big deal ot hop up on the roof and undo 4 screws.

This kind of bracket might work, but it would be a lot of effort to do:
http://pages.prodigy.net/jimmcshane/lbrkt.jpg
http://www.jacksonampworks.com/images/uj_filtercaps.jpg

Anyway the AC is working (or was for the two hours I was there) and the trailer is not moving anywhere for a while, so I have time to sort something decent out.

Do you know what those unconnected connectors are for in my first photo? Just curious...

lewster · 08-24-2007, 11:30 PM

Quote:

Originally Posted by grantb4

Do you know what those unconnected connectors are for in my first photo? Just curious...

Every Dometic unit is set up at the factory for the potential use of multiple units. A/S is one of the few OEM's that only use one roof air. I've seen as many as FIVE used on the 45' Prevost bus conversions.

Anyway, that extra RG-6 connector is used for the first A/C unit to communicate with the other(s) present, as they are connected in series and the t/stat uses a digitally encoded signal to control the other units from that extra plug. Just wire tie it back into the ADB (air distribution box) out of the way and forget it's there.

Minnie's Mate · 09-04-2007, 02:53 PM

Well, I seem to have been bitten by this dog. Over Labor Day Weekend we went out for about three hours on Sunday afternoon. When we returned the A/C had tripped the 20 amp breaker. When I reset it, the fan came back on and the compressor seemed to start. Two hours later, it was no cooler than when we first got back. I thought the unit may have frozen up so I turned it off for about three hours and tried it again about 10:00 at night. We could see the lights dim when the compressor tried to start and could hear it try but it would almost immediately shut back off and only the fan would run. Fortunately, it cooled off into the mid-70's Sunday night so we were fairly comfortable with the fantastic fans, and we were leaving Monday morning. One of the things I had ordered from Camping World a couple of weeks before we left was a voltage meter, but unfortunately it is on back order.

Does this sound like the controller board, blown compressor, or something else?

lewster · 09-04-2007, 07:23 PM

Quote:

Originally Posted by Minnie's Mate

Well, I seem to have been bitten by this dog. Over Labor Day Weekend we went out for about three hours on Sunday afternoon. When we returned the A/C had tripped the 20 amp breaker. When I reset it, the fan came back on and the compressor seemed to start. Two hours later, it was no cooler than when we first got back. I thought the unit may have frozen up so I turned it off for about three hours and tried it again about 10:00 at night. We could see the lights dim when the compressor tried to start and could hear it try but it would almost immediately shut back off and only the fan would run. Fortunately, it cooled off into the mid-70's Sunday night so we were fairly comfortable with the fantastic fans, and we were leaving Monday morning. One of the things I had ordered from Camping World a couple of weeks before we left was a voltage meter, but unfortunately it is on back order.

Does this sound like the controller board, blown compressor, or something else?

If the compressor is laboring to start and is at the point that it is dimming the lights, it's a good bet that the start cap and PTCR are shot. When you remove the shroud and open up the electrical box (right side) you will probably find a burnt mess. If so.....easy fix!

Minnie's Mate · 09-05-2007, 11:51 AM

Quote:

Originally Posted by lewster

If the compressor is laboring to start and is at the point that it is dimming the lights, it's a good bet that the start cap and PTCR are shot. When you remove the shroud and open up the electrical box (right side) you will probably find a burnt mess. If so.....easy fix!

Even so, it's kind of frustrating. We've stayed in a couple of state parks and a couple of private parks and the rest of our camping has been a couple of stays at Topsail Hill and several stays at Ft. Wilderness Campground at Disney World (4 stays) and we have used the A/C on all trips except two when we used the heat pump. At least the unit is still under warranty and it should be a freebie this time.

Other than the voltage meter, what can I do to prevent this in the future? Camping World has a surge guard, but it is $269. Is that necessary?

lewster · 09-05-2007, 10:54 PM

Quote:

Originally Posted by Minnie's Mate

Even so, it's kind of frustrating. We've stayed in a couple of state parks and a couple of private parks and the rest of our camping has been a couple of stays at Topsail Hill and several stays at Ft. Wilderness Campground at Disney World (4 stays) and we have used the A/C on all trips except two when we used the heat pump. At least the unit is still under warranty and it should be a freebie this time.

Other than the voltage meter, what can I do to prevent this in the future? Camping World has a surge guard, but it is $269. Is that necessary?

MM,

Unfortunately, there isn't much you can do to prevent the dreaded SCS (Start Cap Syndrome)

. It is really a function of ambient temps, amp draw, available voltage and the general condition of the unit. I have seen new units blow the start caps (less than a week old) and have seen 10+ year old units with the original caps. Best insurance (and cheap too!) is to carry an extra hard start kit with you in case you blow the start cap and PTCR again.

Minnie's Mate · 09-06-2007, 07:59 AM

Quote:

Originally Posted by lewster

Best insurance (and cheap too!) is to carry an extra hard start kit with you in case you blow the start cap and PTCR again.

Not exactly what I wanted to hear.

SilverCabin · 09-06-2007, 08:38 AM

Quote:

Originally Posted by Minnie's Mate

Not exactly what I wanted to hear.

Ditto!

Don't forget the ladder to get on the roof to make the changeout...

Randy

Minnie's Mate · 09-07-2007, 09:05 AM

You know, over the 4th we were at Ft. Wilderness and I forgot to lower the awning when we went to dinner (I usually lower the rear arm all the way when we leave). While we were gone there was a torrential down pour that resulted in the rear arm being bent all the way to the ground. It literally had a 90 degree bend in the inner segment that was extended. Well, Disney maintenance wouldn't loan me a ladder and I called several of the on-site repair companies and they advised me to find a ladder because they charged so much to come out. The minimum I think I was quoted was going to run about $240. There just happened to be a mobile service company at one of the sites across the road from me a few days later (I had managed to retract the awning, but couldn't get the rear up high enough to secure it) and the repair tech came over and got out a folding ladder that was the size of a six foot long 4X4. I was impressed with how small it folded and unfolded to a regular width A-frame ladder. So I ordered a five foot length one to fit under the sofa in our Airstream. If it was an 1/8th of an inch longer I would have to put it under at an angle, but it fits perfectly and leaves plenty of room to store other items.

Here is a link to the one I got:
5' Compact Folding Step Ladder - Camping World