I need to replace the compressor. The label says R-12. Are replacements available or am I forced to convert to R-134? Do I have to specify what refrigerant when ordering the compressor?
Thanks,
Bob
Bob,
R12 was phased out in 1995. I would be very surprised if a 1997 coach had R12.
The good news is that the fittings for both high and low pressure are different between R12 and 134A. That would be better indicator than a stick-on label or what original refrigerant (and different oil) was in there when the compressor was manufacturers.
And, speculation on my part, but suspect that a compressor would pump either refrigerant, so would not base my decision on coolant on a label from a compressor that may have been on the shelf at Foretravel for 2 years.
So, it may be as easy as dumping the oil and adding the correct oil to change a compressor from R12 to 134A.
You would do well to go to a site such as Automotive Air Conditioning Information Forum - Index page (http://www.autoacforum.com) or Automotive Air Conditioning Information Server: Home (http://www.aircondition.com) and ask your questions. There are friendly experts there who can help guide you to which parts need to be replaced and how to get the results and performance you want.
Where can I go to see what the fittings look like?
Bob,
Just google (or other search) for: fittings for R12 vs 134A.
I promise you, gauges for R12 will not fit on systems with 134A and visa versa.
The fittings/ports for high and low are different.
They are R-134A fittings. They have internal threads.
My high pressure hose to the condenser needs to be replaced. Is that an item available through a refrigeration supply house.
Speculation, as I have not replaced that hose, but can't imagine that there is anything unique about the fittings on Foretravels.
Take the hose off, seal off the open ends of the system to prevent moisture intrusion and take it to a good hose shop (call around to find a shop that makes automotive A/C hoses).
Thanks for the advice ^.^d
Bob
Any time the system is opened the refrigerant should be reclaimed, the receiver/dryer replaced and the system evacuated and recharged.
The decision has been made for you. The price for the old gas - R12 - will make you gasp. Convert and you will be OK. 134A does not seem to be as efficient as the old gas though.
Keith
But, to convert requires a very complete flush, as the lubricating oils are NOT compatible.
That's why you see all those ads,"just needs freon".
Do your own research, but many people are using a hydrocarbon refrigerant (butane, propane, mix) to replace R-12. Lots of discussions on this but could be worth your time.
Get your popcorn ready.
You said you have
R134a fittings, and if you need a compressor and have a leaking hose you probably have no Freon in the system to worry about. Buy the correct compressor for your coach change the hose and the drier-filter evacuate and charge the system with 134a The compressor will have the correct oil in it normally. There is a label telling if the oil is in the compressor. There is information or Barry's site giving the amount of oil to use if the compressor comes dry.
I would consider not fixing it but tell the buyer exactly what it needs,our 96 has r134 and cools good,if I were doing mine I would flush the lines and convert to r134.
Lots of good advice for anyone needing to convert from R12 to 134A.
But, this quote ENDS the need for discussion of converting HIS SYSTEM from R12 to 134A since his is (as it should be for his model year) 134A.
Propane has the same cooling characteristics as R22.. lots of discussions on the use of propane ( it is not RV propane) and really cools . I have sued it to replace R12, R234A, ext... It is really cold,as is R22.... Let the controversy begin !
Safe travels,
Dave
Have you ever see. The potential damage from propane instead of freon. Local radiator shop had a car in for ac issues. Some one had charged the system with propane. Luckily no one was in the car when the dash exploded.
Are PAG 10 or PAG 20 refrigerant oils still relevant in our coaches? New compressor came with PAG 150. Hard to tell how old the below information is.
Dash Air Conditioner Refrigerant and Oil Capacity (http://beamalarm.com/Documents/dash_air_conditioner_refrigerant_and_oil_capacity.html)
Bob,
You should always default to the compressor recommendations on oil specs. Being you are not sure what oil was currently used or how much residue oil is left in you system you may consider a system flush. Since I'm been in the refrigeration industry for over 40 years mainly the supermarket and HVAC field I can tell you system cleanliness and correct oils are often overlooked. When I bought my 2001 U320 the dash air didn't work, the compressor was the wrong size (same physical size as the correct one), bad discharge hose. I wish I would've taken an picture of the junk that came out, burnt oil and compressor reed valves, so I believe this dash failed quite frequently. I cut open the existing drier/receiver and it was black and plug, I install a larger drier/receiver mainly because I live in area that gets over 115 degrees, I need to have enough refrigeratant to operate in cooler climates. If you do flush your system you need to replace the oil in the hoses and drier, I used about 1/3 of a quart of oil on mine. A neat trick is to add service valves between the compressor and hose connections. This way you can blend off the pressure on the compressor and on top of the compressor there is a 1/4-20 bolt that you can remove and use a makeshift dipstick to check oil level, Sanden sells one.
Last note, in my system the compressor never shuts off unless the dash t-stat Is satisfied (no suction pressure sw installed) therefore suction pressure at the compressor are lower (mine was about 18-20 lbs) so slow oil return and higher discharge temps seems to be normal.
So far in 115 degree summer I only use the dash air and never needed roof air so Good luck with yours,
Steve
Willy, helped with mine and he got it up and running and still running cool... He was a great help.. ^.^d
I want to give a shout out to Steve White (AKA Willy White) for his invaluable advice/guidance concerning our dash air. This project was successful as a result of his patience/understanding. Final results was dash air @38ºF
with 70ºF inside temp.
Bob
What were the main issues and corrections for yours? I'm having chronic problems with my dash AC as well. Pressures are always too low on the low side or too high on the high side, per the charts. And cooling is only 15-20 deg below ambient. It's probably been in the shop for AC problems half a dozen times in the last year. New compressor, 2 different expansion valves (from FT), expansion valve manually adjusted to tune pressures, flushed twice, new condenser coil fan, new dryer, heat wrapped the exhaust at the condenser...nothing seems to help. The shop is willing to keep trying as soon as the weather warms up, under warranty, but they're stumped.
For that money you could probably figure out how to mount a 5000 BTU cheap window unit behind the dash and the inverter to run it .
I would suggest a new condenser (perhaps a larger size). Also check online with rhe guys at aircondition.com and ackits.xom.
I think it's actually getting good temperature drop across the condenser. 176deg in, 142deg out for a 34deg difference.
5000 BTU is way too small for a dash unit. You really need 12000 BTU or more in a dash unit. Lots of "greenhouse" heating with all of the glass areas around.
The low pressure for my coach is below the chart, usually around 20 psi to get the cooling system to work. I haven't figured out the reason, but if it works don't mess with it.
99's have a bigger dash ac unit.
Squirrel cage motor fans can slip on the motors shafts
They can also run backwards if miss wired, airflow still comes out the vents in the normal direction, but volume is only 70-80% of design.
I have 5000BTU unit on the back part of my little house. Cools 400sq ft no problem . I would think that it would cool the front 15 ft of my bus with no problem . As it is now, I just run the overhead ac and genset if it gets warm . Since I added a one wire 100 amp alt, I should have enough alternator capacity to run an additional inverter , but have not done the math and so far it is a non issue .
There seems to be room for it in the grille.
Good luck, Foretravels have big front windows, I have a 28000 btu dash unit, and it just barely keeps the first 3 ft cool, on a hot day.
Jcus, have you converted your dash unit to a window unit? how is that done?
No, my point is that if my 28000 btu ac barely keeps me cool, would not expect a 5000 btu ac to do much for you. BTU's are the amount of heat your air conditioner can remove.
You can use this calculator, but bear in mind that windows provide very little insulation and will allow the sun to heat the interior of the coach.
BTU Calculator (https://www.calculator.net/btu-calculator.html?roomwidth=10&roomwidthunit=feet&roomlength=10&roomlengthunit=feet&ceilingheight=6&ceilingheightunit=feet&insulati)
Consider the difference between cooling a 400 sq ft (typically insulated) room and cooling a 400 sq ft greenhouse on a sunny day. The "greenhouse effect" in a vehicle is real and significantly adds to the heat load.
I have a 200 ft roll if 3m clear for the windows. Blocks uv and heat. Going to do all of them. Including the windshield