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Air conditioner turns on but won't blow...


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Hi Friends!  Air conditioner turns on but won't blow, in fan mode or in AC mode.  And after a minute or so, overhead AC just rumbles off all on it's own, and stays off.  I imgaine it could be a number of things, but if it's not blowing period, could it be a malfunction/broken fan?  Besides getting a Pro to look at it, anything I can do to try and fix (at least the fan prob)?  I've removed the inside filter/cover inside the cab, but haven't climbed onto the tall tall roof to investigate.

 

Thanks!  Max

 

1989 Micro Spirit

Connected to 30 amp shore power so all good on electric

Edited by ATXBreeze
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Tree branch in the fan? Can you UNPLUG the RV, remove the inside control panel, and see if you can turn the fan by hand. If not, then its up to the roof and remove the shroud and try the same thing. The RV AC have 1 motor with a different fan on each end.

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Yep, that's the critter. It should be held on by small screws. There are 4 large bolts DON'T undo them, they bolt the AC to the roof.

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With the AC/fan in the ON position, I could see that the fan would not engage/spin.  I turned the AC off,  reached in there and gave the fan a hearty spin (it took me two times). I turned the AC on while the manual spin was still going and it engaged and began to spin at what felt like it's normal "on" speed. However, when I turned the AC/Fan off, waited a moment, and turned it on again the fan again would not spin.  When I repeated the manual hearty spin trick, fan would engage and spin.  The fan feels just a touch stiff on its turning bearings. I'll oil tomorrow and see if this gets it completely free to spin on its own (or if you have another suggestion).  Thanks for all your help. 

IMG_5321.jpg

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If both fans run on the same shaft from the motor, my guess is that there is crud on the top fan slowing them both enough to prevent them from engaging by themselves. Somebody needs to get on the roof and remove the shroud. It's not uncommon for lots of crud building up there. Bug nests and all kinds of stuff. Bet yours has never been cleaned so it's something that should be done anyway.

Linda S

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Quite possibility a bad start cap. You will need to remove the shroud up top and try to find the starter cap. Most likely this is a pro level job unless you have electrical skills.

Might, maybe a hot start cap would be a easy fix.

https://www.ebay.com/i/124019608687?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=124019608687&targetid=935083617067&device=c&mktype=pla&googleloc=1028450&poi=&campaignid=10454521883&mkgroupid=104612010380&rlsatarget=pla-935083617067&abcId=2146002&merchantid=101722447&gclid=EAIaIQobChMImqy42dKw7AIVuT6tBh12xw4YEAQYAyABEgLlUfD_BwE

Edited by WME
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Sounds like capacitor,  job for a pro.  Definitely not beyond the average persons skills with a bit of You Tube help.   In lieu of a meter that will test farads some people buy a replacement capacitor,  if it is not the issue then have a spare capacitor.  Unplug RV before jamming screwdrivers into electrical stuff on the roof  LOL.

 

 

Edited by jjrbus
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I removed the shroud, re-connected elect.,  turned the AC on and the the top fan came on, but the bottom one remained off.  There are two fans, one that looks like a common bladed fan, located under the shroud, and a barrel type fan, located closer to the interior of the cabin.  They do not operate on the same motor)  Anyway, my manual spin trick got the whole system going so there's something wrong alright.   Thinking of replacing the  start capacitor with the one recommended by  WME . I can do electrical, but if someone could please confirm that said part,  the Coleman RV A/C HARD START KIT DIY no wiring easy CLIP ON (look at the above link) will indeed work on my 1989 Micro Spirit AC unit, I'd appreciate it. 

 

It was dirty under the shroud Linda,  (mud dauber nest, dirt, leaves), but looked ok otherwise.

 

ALSO, does the start capacitor replacement recommended here works in conjunction (or over rides, not entirely sure) the existing faulty start capacitor. Can I just not replace the faulty capacitor? Take the old one out, put the new one in?  Is the reasoning behind the "Coleman RV A/C HARD START KIT DIY no wiring easy CLIP ON" because it's easier to get up and running? Because it's less expensive than the existing replacement part?  Online, some folks think the Coleman RV A/C HARD START KIT DIY no wiring easy CLIP ON (and other similar brands) is temporary, not quite a best practice solution/fix.  Please let me know your recommendations and opinions, I really appreciate them :)

 

Thanks everyone!

Edited by ATXBreeze
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You should have a total of 3 capacitors under the shroud. Take pictures of the wiring, copy the numbers off each capacitor, and order all new through Grainger or similar electrical supplier. You don’t need Coleman parts. Capacitors are capacitors. I did this with my Coleman mini-Mach this summer. Runs brand new. You can also add a hard start to the start capacitor if you want.

Total cost was less than $100 doing the work myself.

Electrical components all have a mortality rate. Chances are if one capacitor fails, the others will soon follow. Rather than spending lots of time troubleshooting, just replace everything.

Edited by fred heath
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Yes pictures please of the AC its self and the wiring diagram if you can find it.

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Wiring diagram usually attached to the rear of the capacitor protection cover.

I took many photos of wire color and location on capacitors. You may have to remove the capacitors one at a time to access the printed identifiers on each capacitor. They are usually nested together. As soon as you get the information, reinstall the capacitor and reattach it’s wiring. Wait until you have all the new equipment in hand, then start the replacement one capacitor at a time.

This is how I did the work.

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2 motors on a Duo Therm Brisk air?? Can you post a picture of that?    I have the schematic for Brisk air if you know model #  

 

If a hard start has already been installed and failed it can stop the compressor from starting. 

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I'll take pictures of the un-shrouded unit today and post. When both fans are blowing (remember, the bladed fan on top does start on its own, and  I manually spin the barrel fan to get it started), and the AC set on high, it blows plenty cold.  It's not the compressor.  It's just the barrel fan (upper right box in photo), the one I can see when I remove the housing on the inside of the cabin, that won't engage on it's own.  Maybe they're both on the same motor, but that wasn't visually apparent when I removed the shroud cover on top.  That bladed fan went directly into an electric motor.   I can not see what's driving the barrel fan.  

IMG_5320.jpg

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The hot start cap is for the compressor, not the fan motor. So if the compressor is running OK then a hot start cap is not the answer.

You need the wiring diagram to see what the fan motor start cap is.

 

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From the left field peanut gallery🤡 Is the squirrel cage fan (inside) tight on the shaft or is it slipping?

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Good questions. It' hard to tell about the squirrel cage fan being tight or not. When I spin it, it rolls plenty smooth.  The following has occurred to me.  The big electric motor on top, the one under the shroud that propels the bladed fan (which starts/works), sits right on top of the squirrel cage fan, which is part of the inside control panel and directly below it. I wonder if there is a pulley behind the electric motor, and if there is a belt that connects from the pulley to the squirrel cage fan. And if that's slipping. I need to take the shroud off again. The back of the electric motor is covered in a sheet metal box, which if I remove, may expose the problem.

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OK, removed AC shroud and went inspecting.  The electrical fan is directly connected to the bladed end in front, and connected the squirrel cage fan in back.  When I turned the bladed fan by hand, the squirrel cage fan turned along with it.  I originally thought the squirrel cage fan was underneath driven by a cable. Wrong. What I was hearing while in the cabin, when I turned the ac on, was the compressor kick in (which it still does)  I'd reported that the bladed front end started when turned on. Nope.  Neither the Bladed front spin, nor the squirrel cage fan spin when turned on with the inside control panel because, as it turns out, the electrical motor does not start. I removed the the lid to the box containing the capacitor (last photo). Looks like the original. So, It's either the capacitor, or a moribund electrical motor.  As previously reported, when I manually spin the squirrel cage fan, the electrical motor does start. It spins the fans, and the  AC kicks in and blows strong cold air.  I guess I'll start with replacing the capacitor, unless somebody weighs in other wise. All input appreciated!

 

Thanks for looking and for all your help everyone!  (last two pictures uploaded sideways, sorry. When I flipped them correctly, upload would crop them).

 

WME, I concur, I think it's a 2 in 1. 

 

EDIT: I found an identical capacitor on ebay for $6 (described as working when pulled), so this may be step one.

 

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Edited by ATXBreeze
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Great we're all on the same page.

Is that the only capacitor in the AC unit or is there another one near the compressor? Did you find a wiring diagram?

A big guess is that the cap is 2 in 1 and is a start/run cap. There is a bunch of wires on that cap. Does a set go to the fan motor AND the compressor?

The ac power goes into the smaller box can you remove the top and see what is inside/

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Unless you have a meter to test farads,  there is no way I would buy a used cap off Ebay!   You can walk into most HVAC suppliers with that capacitor in hand and they will sell you an equivalent one. 

 

This is an equivalent cap 15+5 uf    370 volts.   As long as the round will fit in the box.

 

https://www.amazon.com/Motor-Capacitor-Round-15-12703/dp/B00C0YSDKI

Edited by jjrbus
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Hey jjrbus! Not knowing the first thing about capacitors, a few additional questions. 

 

The existing capacitor is "flattish", the Amazon one you recommend round.  I'm sure this is a non factor, but please confirm its ok. Plenty of room, btw, it'll fit.

 

If the Amazon recommended capacitor is not a perfect match, can I harm the system?  

 

And the most important thing - the wire connections, and where they go.  I imagine they must match exactly (the red wire goes in the red wire spot, the yellow wire goes in the yellow wire spot, etc. 

 

I took a crappy picture of my capacitor with a little more info, may provide matching information, attached.

 

Thank You! 

IMG_5347.jpg

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20 years ago all I knew about AC was turn it on turn it off and clean the coils.  12 years ago I moved to Florida and was shocked and outraged by what AC people are getting away with and have tried to learn what I could.  So not an expert or AC tech by any means.

 

A simple explanation is it is very similar to a battery,  it stores electric.  So when handling one need to be careful,  they can have enough voltage to kill! 

 

Like a battery if the specifications are the same,  even though the battery or capacitor is shaped differently if it will fit it is good to go.   Can use different voltage,  but I have to look that up.   The 15+5 UF are important,  ie Farads.  15 farads to kickstart the compressor and 5 farads to kickstart the fan.  So I would use it.

 

https://www.youtube.com/watch?v=ZTQi5rTJIw8

 

Very important that you get the wires in the right place,  take a few pictures before you disassemble.  C is common,  Fan is self explanatory and herm means compressor. 

Edited by jjrbus
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Great video on how to discharge both old and new capacitor, thanks.  The guy who did the video commented that discharging the old, *still connected* capacitor (no shore power on of course)  is okay, too, with the same procedure. Can you confirm that discharging a capacitor that is still connected is ok.  As far as switching the wiring from one the old capacitor to the new,  seems straight forward, just duplicate the order, correct: Common, Fan, Herm

 

About to order your recommended capacitor replacement

https://www.amazon.com/Motor-Capacitor-Round-15-12703/dp/B00C0YSDKI

Will report how it goes.

 

Thanks so much!

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With electric off,  I do the best I can to discharge the capacitor with it in place, difficult to do with the wires in the way so use insulated pliers to remove a couple.  I also discharge it after getting all wires off to make 100% sure it is discharged.   Says 380 volts on the capacitor and even at low amperage that is a lot of volts.

 

Keep in mind everything I post is my opinion based on my experience and worth what you are paying for it!  YOUTUBE CERTIFIED Master TECHINICAN superb Patch Hook and Loop | Etsy

Edited by jjrbus
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