Thermostat wiring for Mach8 basement A/C '99 Vectra
My A/C quit and I found the fuse behind the thermostat was broken. Then I made a BIG mistake... I unplugged the thermostat to take it and clean it out nicely - when I got back, the 9 pin plug was still hanging out the hole but the 3 pin for the furnace had dropped back and I just can't find it!?
I'm sure it is somewhere between the wall and the refrigerator but I was hoping to to have to mess with it.. Im able to push a wire from the hole behind thermostat all the way down to where I can see it but I can't identify which cable set that IS the three wire going to the furnace!? Any suggestions? Can anyone tell me if its three individual wires or are they encased? The colors on the thermostat are black/red and purple with stripe.. I can't get the A/C to work without supplying power... I greatly appreciate any assistance/suggestions y'all have...
Thanks!
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'99 Winnebago Vectra Grand Tour 37B
First time owner
I don't know your floor plan, but I sort of get the impression the toilet is on the other side of the wall. If so, you may have an access panel on that side that will give you access. ...Worst case, maybe you will need to make one?
Your other option is to take a picture... inside the wall to see if you can spot your missing wires; and then try to hook it with a coat hanger. Also, your camera will show you real-time footage. Just be sure you don't drop the camera inside the wall, which I have almost done a few times.
Below is a 2004 wire diagram of my thermostat (to my Coleman Basement AC) which my help you, but maybe not. Your wire colors sound different, but I bet the plug types are the same.
I've got some AC running now I simply took my old 12Volt CB power supply and wired it to the thermostat and was able to fire up one compressor and all required fans to run.. I've still not been able to figure out why my second stage compressor won't kick on/punches the fuses but that's alright for now.
95ºF and 85% humidity suck the fun right out of you, i tell ya!
Thank you so much!! I'll probably run a new wire from thermostat down to the furnace later on.
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'99 Winnebago Vectra Grand Tour 37B
First time owner
Anyone who knows humidity is an important metric has some handyman experience or better. So what's your background?
IDK, is a Mach-8 the predecessor to the Coleman Mach (2-Ton) basement AC? I ask, because I don't want to post technical "stuff" that does not apply.
Is this a new RV to you? Has your #2 compressor ever worked right? Either way, sounds like you need to check the values of your RUN & START capacitors.
Also, if you have a Motor Starter (PTC-R) you should be able to measure 20-25 ohm on the bench... and it should have continuity. At 1000 ohms it opens the circuit, and maybe that is why your AC #2 compressor will not start?
Note: Finding a motor starter or PTCR is harder than you think. So another way to go is to use a Supco SPP4E Hard Start Kit, that will replace your OEM HSK.
For more information you can check out Post #82 on this thread:
Anyone who knows humidity is an important metric has some handyman experience or better. So what's your background?
IDK, is a Mach-8 the predecessor to the Coleman Mach (2-Ton) basement AC? I ask, because I don't want to post technical "stuff" that does not apply.
Is this a new RV to you? Has your #2 compressor ever worked right? Either way, sounds like you need to check the values of your RUN & START capacitors.
Also, if you have a Motor Starter (PTC-R) you should be able to measure 20-25 ohm on the bench... and it should have continuity. At 1000 ohms it opens the circuit, and maybe that is why your AC #2 compressor will not start?
Note: Finding a motor starter or PTCR is harder than you think. So another way to go is to use a Supco SPP4E Hard Start Kit, that will replace your OEM HSK.
For more information you can check out Post #84 on this thread:
My wife and I acquired this RV cheaply at the beginning of the year, it has sat for a long time and I've done lots of work on it, brakes - suspension, carpentry and serviced both generator and the 454 motor in it.
The AC is a two stage basement A/C and the second stage quit before we purchased it. I have lots of technical training but never owned an RV before.
I've owned a sailboat and worked on aircraft in the Swedish air force until I moved to north central Florida in '97...
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'99 Winnebago Vectra Grand Tour 37B
First time owner
Coincidentally there are a number of relatively recent threads on Winnieowners about these units. Even though they may address different problems than your's, you'll find them informative for future reference. I've taken to bookmarking every basement A/C post I run across in case I might need the info in the future.
This one is just starting but has references to three more threads and a video at the end of my post #2:
Winnebago has a great owner resource sections with wiring and plumbing diagrams, sealant call out sheets, parts catalogs, etc. for various models and years. You should check them out and download as much as you think you might need so you have access without internet service. Sometimes these links get broken as Winnebago fiddles with their website:
It's an 6636-871 manufactured by RVP! It doesn't have reverse valves from what I can see on the wiring/circuit board in the unit. I appreciate the links
On the right side of the home, behind the main door - there is the dining table and behind it, is the refrigerator and spice cabinet. On the front wall of that refrigerator (forward facing) is where the energy management display, solar panel, thermostat for exhaust fan AND the thermostat is mounted. So there is a lot of cables in quite a narrow space. I'll borrow a bore-scope for tomorrow night. I should be able to spot the connector and go fishing :-)
For now - I've just disconnected the lead from the controller board to the relay that powers the 2nd stage compressor so the system THINKS it is running both
I think the second stage compressor is locked - I've swapped compressor #1 and #2 and the 1st ran with all capacitors/equipment for the 2nd but not the other way around. If I can run stage #1 it'll be good enough for now and when it gets cooler (less hot) - I'll be more inclined to work on this - outside.
Vikings tends to melt in the Florida summer heat!
Quote:
Originally Posted by BobC
Having owned a boat and worked on aircraft, a motorhome should be a cinch.
I'm a former sailboat owner.
Are you sure it's a Mach 8? The Mach A/Cs appear to be roof units per Google. You most likely have a 6535 series Heat Pump that cools and heats.
Here's a link to a service manual which should help:
Coincidentally there are a number of relatively recent threads on Winnieowners about these units. Even though they may address different problems than your's, you'll find them informative for future reference. I've taken to bookmarking every basement A/C post I run across in case I might need the info in the future.
This one is just starting but has references to three more threads and a video at the end of my post #2:
Winnebago has a great owner resource sections with wiring and plumbing diagrams, sealant call out sheets, parts catalogs, etc. for various models and years. You should check them out and download as much as you think you might need so you have access without internet service. Sometimes these links get broken as Winnebago fiddles with their website:
You can remove the spice cabinet by depressing the taps on the slider.
I would place a case of water under the spice cabinet for extra time so you can manipulate it back into position.
...And hopefully, you will not lose any ball bearings. That said, you might also have a blanket under the water case to catch them if they fall. I.e., you don't want these "steely" things interfering with your slide rollers.
...And on that note if you do lose any ball bearings that's an indication you should replace the slide. (See my thread on how to do this and you will save yourself a lot of frustration.)
You can remove the spice cabinet by depressing the taps on the slider.
I would place a case of water under the spice cabinet for extra time so you can manipulate it back into position.
...And hopefully, you will not lose any ball bearings. That said, you might also have a blanket under the water case to catch them if they fall. I.e., you don't want these "steely" things interfering with your slide rollers.
...And on that note if you do lose any ball bearings that's an indication you should replace the slide. (See my thread on how to do this and you will save yourself a lot of frustration.)
I don't want to hijack this thread, but can you give us the link to your thread on replacing the slide? I had to remove mine for some cabinet remodeling and it just isn't right.
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Bob C
2002 Itasca Suncruiser 35U
Workhorse Chassis
I don't want to hijack this thread, but can you give us the link to your thread on replacing the slide? I had to remove mine for some cabinet remodeling and it just isn't right.
"We will add your biological and technological distinctiveness to our own. Your culture will adapt to service us. Resistance is futile."
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'99 Winnebago Vectra Grand Tour 37B
First time owner
Also attached is a .pdf of this process. The key is having a very large carpenter's square so you can position the slides at a perfect 90-degrees to your cabinet frame (face).
The next problem is the slide part with the rocker switch to unlock the slide. Winnebago really gouges on on this part. I think it was $100 vs. $22 at HD or Lowes.
The thing is: Both HD & Lowe's only carry locking slides you push-in to release (open). You can use these, but then you have to make sure you leave enough room... for your cabinet to push-in, or they will lock in place and then you really will have a hard time getting your cabinet open again. So be very careful of this.
To my knowledge, Winnebago is the only place to buy the metal roller-bearing-slides with the rocker to release (open) the slide. So If you find an alternative source please let us know on this thread:
Good luck and we're looking forward to you adding to our basement air knowledge base. You have the skills.
Much time has passed but I have finally made some headway :-)
I ended up getting myself a replacement Techumse compressor and replaced it for the second circuit. Tried to pull a vacuum but found THREE leaks in that refrigerant path. After sealing those leaks - i ran a vacuum on it for two hours and charged it.
Now I have it cooling nicely - but before going thru and reinstalling the unit in the vehicle - i am going to work on a hydraulic leak i found in the bedroom slide out that is right above the A/C. Getting the basement unit out was easy EXCEPT the removal of the supply ducting on the back of the unit (between A/C and back cap).
After having it removed - i am wondering if it can't be installed by lifting it straight up from below - instead of sliding it out sideways. If that'd work,
i'd be able to leave the supply duct elbow in place and just join it it to the RVs duct work once the unit is in place?!
__________________
----------------------------------------------------------
'99 Winnebago Vectra Grand Tour 37B
First time owner
It's an 6636-871 manufactured by RVP! It doesn't have reverse valves from what I can see on the wiring/circuit board in the unit. I appreciate the links
On the right side of the home, behind the main door - there is the dining table and behind it, is the refrigerator and spice cabinet. On the front wall of that refrigerator (forward facing) is where the energy management display, solar panel, thermostat for exhaust fan AND the thermostat is mounted. So there is a lot of cables in quite a narrow space. I'll borrow a bore-scope for tomorrow night. I should be able to spot the connector and go fishing :-)
For now - I've just disconnected the lead from the controller board to the relay that powers the 2nd stage compressor so the system THINKS it is running both
I think the second stage compressor is locked - I've swapped compressor #1 and #2 and the 1st ran with all capacitors/equipment for the 2nd but not the other way around. If I can run stage #1 it'll be good enough for now and when it gets cooler (less hot) - I'll be more inclined to work on this - outside.
Vikings tends to melt in the Florida summer heat!
Bringing up the service manual for your specific heat pump requires the letter behind the 6536, it will be an A,B.or C
__________________ 2000 Winnebago Ultimate Freedom USQ40JD, ISC 8.3 Cummins 350, Spartan MM Chassis. USA 1SG, retired;PPA,Good Sam Life member,FMCA. "We the people are the rightful masters of both the Congress and the Courts - not to overthrow the Constitution but to overthrow men who pervert the Constitution." Abraham Lincoln
I simply took my old 12Volt CB power supply and wired it to the thermostat and was able to fire up one compressor and all required fans to run.. I've still not been able to figure out why my second stage compressor won't kick on/punches the fuses but that's alright for now.
I stand corrected! :)
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