AC units not blowing cold , Can They be Recharged??

[stetler]

Both of my roof AC units don't seem to be blowing real cold air. At about 1' away from the vents at the main AC unit it feels almost room temp. but at a few inches from the vent its definitely colder.
Takes WAY too long to get the coach to cool down.

CAn these units be recharged? Is it the same as a Home AC recharging Freon?
Or do I HAVE to take it to a RV repair place like Camping world ?











Also anybody have any idea what these antennas are for ? 1 in the front and 1 in the back. Both are broken off.

[Ray,IN]

The antenna are for radios. Looks like you have an AM/FM radio near the driver and one elsewhere in the MH.
I don't recognize the A/C units, but every one must have an identification tag somewhere with brand, model, refrigerant, serial#. Yes, it can be recharged; the technician must first install a tap in the refrigerant lines. Any competent air conditioner technician should know what to do and how, as they are not significantly different than a window air conditioner for a house.
Before spending any money, check for a cross-plenum air leak between cold-output air and warm intake air. Use metal duct-tape to completely seal any openings where intake air can blend into cold output air.

[Slice]

One is CB the other radio. Yes ac can be charged. Rv shop people will not do it. Easier to sell u a new one. Which don't work as good as the older ones. The unit takes r-22 freon. A line tap is needed. And someone with skill to put the correct amount in.
Find ac guy wanting extra cash onside. Easy peazy. If ur in Houston Tx. Pm me I can help out.

[Streetrod37]

All a/c can be charged. They may have to ad service valve to do it and if it's R-22 it will really be pricey. I used to pay $35 a drum now it's close to $ 700 dollars a drum so shop around

[MtnTrek]

Welcome,
Depending on where you're located, a 40' coach is not going to cool off very quickly with 2 a/c's if is 113 deg.

Your A/C units are closer to window units than central types. Meaning they have no service valves they are hermetically sealed. So if for some reason there is not the correct amount of refrigerant in them it must have leaked out. A tech would install a service valve, repair the leak(s), evacuate, then recharge the system with the correct refrigerant charge.
If the refrigerant can get out, air and moisture can get back in so a compressor if still operating (?) has a shortened lifespan. At 12 yo could be dicey.
They look like they're in decent repair. Good pics BTW. Have the other system aspects checked: filters, duct, plenum, make sure those coils are all clean, electrical.
Those look like FM radio antennas to me too, one dash one entertainment center.

Happy motoring.

[simplecamper]

OK my first post.

I was HVAC NATE certified tech so I know a little something. I am a software engineer. Need to find the cause first. The refrigerant does not dissipate if low then it has to have leaked. If the compressor is not working then of course the refrigerant can not circulate. The compressor could be simple as a capacitor dead, that is not expensive. compressor bad buy new.

I have not worked on RVs before but the units look pretty close to window units in different form factor.

Just adding refrigerant will only be a temporary fix. You will need a multi-meter, gages, temperature clamp or sensor and know what to with them. A leak detector is also needed. So find an experienced HVAC person who has worked on RV.

Quick look at camping world new units look to go from ~$500-1000. Heck I charged $100 just for a trip charge. I would not bother fixing a leaking coil, buy new. one can solder a patch, need a torch and solder etc...

[adamfolger]

Yes they can be charged but there are other reasons they may not be blowing cold. Pull the covers off and see if the fins are dirty. You can spray them with air conditioner fin cleaner from Lowes and spray them with a water hose. Lack of air flow thru the cooling and exhaust fins is the most common cause of poor air conditioner performance. It seems unlikely that they would both be leaking refrigerant.

[epj]

Also, if they have a common thermostat, as some units do, it could be faulty.

[TXiceman]

I do not recommend recharging an RV A/C unit unless you can get it done properly and at a reasonable price.

The piercing valves are temporary and they will leak. You use them to access the system to properly remove the old refrigerant. Then you flow a small amount of nitrogen in while soldering the NEW Schrader connection. Next you use a vacuum pump to evacuate the system into a deep vacuum to clear the air and water vapor.

Once the system is evacuated, you break the vacuum with refrigerant and finish charging the system.

To get this done properly and professionally done, you will spend 1/2 the cost of a new unit and have basically no warranty on it. A new unit will carry a full warranty.

I worked in industrial refrigeration and can tell you, it is easy for someone with the knowledge and equipment. There are a lot of hacks out there that can claim to recharge a unit, but I would not let them touch my unit.

Check the air temperatures at the unit inlet and outlet. Run the unit on high fan. The leaving air should be 20 degF colder than the entering air. Use a thermometer and not an infrared temp sensor. The infrared will not measure air, only the metal or plastic.

You should check the sealing of the duct at the unit and make sure you are not leaking air from outlet back to the inlet side. Also make sure to seal any holes where wiring comes into the unit.

My 2 cents worth.

[TQ60]

Do not waste time charging.

If both not working then it may be stupid simple like a control problem running in fan mode.

First action is to locate the model numbers and often there is a nomenclature tag under the cover inside the rig.

Maybe need to pull cover on roof.

Look on the back of all of the doors or in your paperwork for a build sheet.

With that and Google get a copy of the service manual and read it 3 times.

Now verify your thermostat is set properly then perform the troubleshooting per the manual and you will get the issue determined fairly quick.

Both units not working at same time indicates a common issue so if single thermostat the issue is likely related.

[stetler]

OK. I couldn't wait until the weekend to clean them and see if it fixed the problem. Today I went over to my brothers house and took off the covers. They actually looked pretty clean. I soaked them each in Simple Green and hosed them out with clean hose water. Making sure I didn't hit the fins with full stream & bend the fins. Now I've hosed out my last toyhauler ac units WITH the covers on and seen a bunch of dirt flow out of them. These however didn't have much of anything come off them.
Went inside and laid a tarp on the ground in case any water came thru. Good news is Nothing came thru. Pulled the inside covers off and cleaned the black mesh filter on both.
In the end. NOTHING CHANGED. Still horrible air flow from the back ac and not very cold on either.
What I did find out is the back ac unit does not go to a HIGH fan speed. It does kick in to a higher speed then LOW but definitely not near as fast or loud as the front AC in HIGH.
So at this point I think its time just to replace both units with brand new ones. Wondering if my charging system/wiring system will be ok with a 15K or should go lower. Not sure what these existing ones are.
Somebody mentioned that the Thermostat might be bad. That's actually not a bad idea. I've gone thru 3 thermostats at home on the last 4 years. Maybe its not allowing the back ac to go to a higher fan speed and maybe its holding the AC temp to a High 78 deg or so.???
* Whats the deal with the rear AC inside vent ?? Why is it not like the front one that allows lots of air to flow right from it?
Even when I open the front vents that are on the main unit the ducted round vents that are scattered around the cab still have more air flow then the rear ac ducted vents.
In the end I really think I just need to replace both units.

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[stetler]

You know me and pictures. ha ha heres some action shots when I hit it with the first rinse. Not much dirt.

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All back together.

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internal filters.
the cover on the right (Larger one) is the rear. It doesn't allow any air to come out of it.
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I held a Kleenex up in the hole of the AC and the back one BARLEY pulled the Kleenex up in the duct. But the front one sucked it up way better..
Why is this rear vent like this?? Is it suppose to allow the AC to push more air thru the duct system??
rear
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Front vent. This one allows me to shut 3 side vents to allow better flow thru the duct , Lots of air flow out of this. Unlike the rear one.
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[TQ60]

At about the 9th photo there is a device that looks like a gold d cell battery.

That looks like a selenoid that is used on a reversing valve if you have heat pumps.

These reverse the coolant flow which causes it to cool the outside via heating inside.

The valve sometimes sticks.

Test run the unit with cover off and see if outside part gets cold.

Also note the ends of the coils of the evaporator are showing so if there is no insulation over these then you are loosing some cooling there so if you keep these apply some foam over them.

If the fan seems slow and does have correct amount of speeds then the bearings could be drying out which is normal for fans operating with heated or dried air as the grease slowly dries out if ball bearing and if bushing same thing.

Spin fan by hand and it should spin freely.

If not you can get some paint thinner and a coffee stir stick to apply via pouring thinner in tall cup then place stir stick (tiny straw) in thinner then cover with finger.

Hold it next to shaft where it enters motor and spin shaft as you let up finger.

Sewing machine oil with the needle applicator also works.

Bearings are likely 38KDD or similar size and are easy to change at about 6 bucks or so esch.

Most bearing supply houses have them in stock.

[vapor3000]

I would encourage you to wash your condenser from the inside out, not outside in as your picture shows. Actually, only compressed air is required. Soap is is not recommended as a residue is left on the fins which hurts performance. Use a condenser coil cleaner which will rinse clean with cold water.

I also recommend you take the cover off the evaporator and clean it well. A dirty evaporator really slows air flow and cooling. Again, compressed air is all that is required. A good shop vac to the inlet/outlet fins will help clean the evaporator as well.

My Newmar has ducted heat and air with 8ea 4"/5" dia return air filters which supports both rooftops. I have spare filters and I change these filters weekly. Changing these filters greatly improves the performance of the HVAC. I usually run the fan on high manual and let the compressor for ac which also help.

Once cleaned, measure the amp draw which should be about 12.5 amps for each unit. If they are pulling this amp draw, that's all they will do. If they draw 12 amps or less, the unit is done. It will be cheaper to replace than to try a recharge.