Community Forums

carlh · 05-13-2014, 08:31 PM

Hi
Can anyone tell me what the the total of 134 charge in lb. should be for a 1999 37ft alpine coach.
Thanks Carl

BFlinn181 · 05-13-2014, 08:44 PM

It is usually on a sticker, either near the HVAC plenum or near the compressor at the engine compartment. Be sure to fill with a complete set of manifold gauges so you get the proper amount.

Renipladlo · 05-13-2014, 08:56 PM

Their is a tag on the compressor, follow it's instructions for the lbs of coolant and lubricant to recharge it, if it has a leak, a good service center can put die into the system to find the leak. See my post above for "Dash a/c and things" for the place to take it if you don't know how to repair this system. Be careful, you can get hurt if you don't know what you are doing.

carlh · 05-13-2014, 09:06 PM

Thanks for the info
Carl

Old Scout · 05-14-2014, 07:19 AM

Since WRV used a generic Auto A/C system from ACME Air, I dont think any of the std AC info stickers will be found on our Alpines--IMHO. Think the number is around 4 cans of the std size [12 oz????] freon but you are only guessing unless you are skilled with using a full manifold gauge set and understand ambient air temps, etc. The other issue is determining the amount of oil to added based on how much was lost with the leak. If you have a major leak or replace a component, its also a good idea to replace the accumulator/filter. I really enjoy doing my own work on the coach but the dash A/C is [IMHO] about an 8 out of 10 on the DIY scale. The other challenge with pre-electronic fan controller models is the lack of interface between the A/C condenser's need for air flow vs the wax valve set up for engine cooling [I set a box fan in front of the condenser to simulate air flow when checking freon levels] ...good luck....

tiredvet · 05-14-2014, 07:39 AM

Quote:

Originally Posted by carlh

Hi
Can anyone tell me what the the total of 134 charge in lb. should be for a 1999 37ft alpine coach.
Thanks Carl

I put 40 psi in my system.I can't remember where I read that off hand but it has been blowing cold for 2 years (knock on wood).

BFlinn181 · 05-14-2014, 08:46 AM

Quote:

Originally Posted by tiredvet

I put 40 psi in my system.I can't remember where I read that off hand but it has been blowing cold for 2 years (knock on wood).

I assume you are talking low side pressure. But, at what ambient temperature? That is a very important factor to consider when checking charge of A/C system. As Renipladlo said, there's more to charging an A/C system than hooking up a can of coolant and noting low side pressure.

tiredvet · 05-14-2014, 10:04 AM

I will admit that I purchased a two can pack with gauge at the auto parts store and put in 40 psi (low pressure side). Call me lucky or foolish but I not going to sweat it.

Renipladlo · 05-14-2014, 03:25 PM

The compressor (engine) has a sticker on it telling you all the data. It's hard to see, but it should be there, if not, mine is there, and I can tell you what it says once I am up at the coach, Cummins was able to read it so mine is in place.

carlh · 05-14-2014, 10:58 PM

Thanks everyone for the replies. I have some back ground with refrigeration (30yrs) There is frost out of the expansion valve into the evaporator and the bends on the condenser are warm, the sight glass on the receiver shows coolant flow but not a clear sight glass as it should be. The engine fan is running at slow speed so there is air flow over the condenser. The ambient air is about 70deg. I have put in about 6lb. of r134 and that seems to me like that should be enough. But low side gauge shows 0 back pressure. It looks to me like I need to add more 134 and that is why I ask if someone knows about how much these systems hold. There is no info on the compressor and I cannot find it elsewhere.
Thanks again
Carl

Old Scout · 05-15-2014, 08:02 AM

So how many OZs is 6 lbs?----sounds like too much as the volume on my 03 is around 4 12 oz cans--besides, after 6 lbs of freon, 0 psi is a really low number [smile]. Think you have a blockage or a leak?????? Again, unlike a specific car or truck, ACME made these systems for a variety of application, so I would think the amount of freon is dependent on the application--doubt if WRV posted it anywhere--just saying....
PS--with frost on the evap and some heat on the cond coil, it seems you would register some psi, are you sure your gauges are working correctly?

1peddler · 05-15-2014, 11:07 AM

We have a 40FDTS. Per WRV tech people back in 2009 the correct charge is 3 lbs 4 oz.

Nick-B · 05-15-2014, 01:27 PM

Carl,

With R134a the sight glass should not flow clear. That only applies to the older R12 Freon systems. Sight glass is just a reference to verify you do have flow.
R134a is very sensitive to fill volume and can perform worse if overfilled.
If you cannot find the proper fill information (looks like Dennis may have provided that) and you really want to DIY, just fill a little at a time until you have cold vent air. Just a reminder, as you have AC experience, the correct charge fill is for an empty evacuated system.
Best of luck! Its that time of year we all want working AC.

Pollo man · 05-15-2014, 01:43 PM

After repairing our 2000 38' dash ac last year, I was able to put in about four 12 oz cans of 134a.
Six lbs!? Sounds like too much.
Thanks to all on Irv2, You Tube and Richard from Acme for helping with the repair.
Two pieces: the expansion valve and the dryer/filter required replacement.
Both replacement parts were purchased from Richard at ACME.
Harbor freight supplied the gauges and vacuum pump.

Gary