Dash ac recharge on class a diesel pusher

[GTMADNS]

Just turned dash ac on this past weekend. It blows cool but not cold like it used to. Is it easy to charge yourself? This is a 2006 coachman cross country. Let me know your thoughts. Thanks

[Busskipper]

GTMADNS wrote:
Just turned dash ac on this past weekend. It blows cool but not cold like it used to. Is it easy to charge yourself? This is a 2006 coachman cross country. Let me know your thoughts. Thanks

Having spent hundreds of Hours and Thousands of DOLLARS - I've just fired up the Generator - turned on the roof air.

Just too long a run with too much to go Wrong.

Beginning of every season I'll just give it a charge - Wally Chargehttps://www.walmart.com/ip/Deluxe-R-134a-Recharge-Hose-and-Gauge/16888796

Seems to last a little longer than the $2,000.00 Repair that I've done more than once.

JMHO,

Going to take a long time to burn $2,000 in extra fuel for the Generator!!!!!!!!!!!!!!!!

[rwynkoop]

crasster wrote:
Really - while you can DIY recharge, it is BEST if you can put the system under a deep vacuum then charge. It's the proper way to get all the air out so there is more pure 134a.

How is air going to get in it, when it still has 134a under pressure.

You can top off a system without putting it to a vacuum first.

It is normal for all shaft / belt driven compressors to leak has over a long period of time. The seals leaking keeps them lubercated.

[dougrainer]

Groover wrote:
Is mine the only one that has a sight glass for checking the freon? That makes it a lot easier to know when you have enough freon in the system. I wish that all AC systems had one.

The sight glass is NON functional on a 134a system. A fully charged 134a system will still have bubbles in the sight glass. Doug

[Groover]

Is mine the only one that has a sight glass for checking the freon? That makes it a lot easier to know when you have enough freon in the system. I wish that all AC systems had one.

[rgatijnet1]

RVER wrote:
I have a question related to this question. I have a gas engine, 2003 in Newmar Mountainair on Vortec engine and first time I have driven it in weather warm, enough to put A/C on in dash, NO cold air, air does circulate through dash but not cold or cool really. I bought this used of course so one thing after another but does it sound like a charge will do it? I do not want to spend lots of money to replace the system but would like to travel with A/C if possible from the dash. IF really hot I guess I could fire up the generator and run house A/C but prefer not to. ALL THOUGHTS WELCOME.

The system needs to be checked out to see if it is low on freon or has some other problem. If your system has a low pressure switch, the compressor will not come on until freon is added, but that is not the only problem that can prevent cold air from coming from an AC system.

[deandec]

My OTR AC system, front and rear AC from engine compressor takes 6 lbs of 134A.

The compressor was replaced about 4 years ago as were the two dryers.

After two years I now get lack of cooling each spring.

Each year I install about 1# of 134a using a gauge set to restore maximum cooling. Auto Zone will lend you a gauge set.

[RVER]

I have a question related to this question. I have a gas engine, 2003 in Newmar Mountainair on Vortec engine and first time I have driven it in weather warm, enough to put A/C on in dash, NO cold air, air does circulate through dash but not cold or cool really. I bought this used of course so one thing after another but does it sound like a charge will do it? I do not want to spend lots of money to replace the system but would like to travel with A/C if possible from the dash. IF really hot I guess I could fire up the generator and run house A/C but prefer not to. ALL THOUGHTS WELCOME.

[GTMADNS]

Well found the problem the wire to the pressure switch was off Along with the drain tube for the evaporator. I assume the truck shop that did the last oil change on the engine and generator knocked them off doing the oil change. Ac blows nice and cold again.
Thanks for input.

[JimM68]

I did mine last year. I spent the bucks on a proper hi/lo gauge set even. Put in a can of freon. I found that the compressor was not kicking on, even though the gauges said the system was full.

Troubleshooting revealed a temp switch on the ac unit had failed. It's purpose is to cutoff the compressor before things ice up, but it was preventing the compressor from running at all.

I hot wired it.
Replacing it is on my list.

[Ivylog]

Another use of a IR temp gun... shoot the end 180 degree tubes on the AC condenser and when all but a couple of the bottom ones are about the same temp as the top ones, you have put in enough freon in the system.

On a system that is only working OK you can do the same to see if it needs a little more freon. You want the fins/tubes on top 80+ percent of the condenser hotter than the bottom ones. If only half of the condenser is hotter you are loosing a lot of cooling capability. Even my 42' DP only takes three pounds of freon.

[dougrainer]

mike brez wrote:

dougrainer wrote:

Ivylog wrote:

crasster wrote:
Really - while you can DIY recharge, it is BEST if you can put the system under a deep vacuum then charge. It's the proper way to get all the air out so there is more pure 134a.

Really, How is air going to get into a system that is still cooling, but not as cold as normal... is still pressurized and has enough freon in the system to work somewhat? Even while working the low pressure side will have 60+ psi in it... how is air going to get in???

Bingo. HOW can air get into a pressurized system? IF the system has been open to the atmosphere, then yes, find the leak, then Vacuum and charge. Vacuum can also let you know if the system has a large leak. Small leaks that happen under pressure, a Vacuum test rarely is accurate. Now, HOW is a novice supposed to know how much 134a to install? Unless you have your gauges connected and do a digital temp at closest outlet to the evaporator, you will have a hard time getting it filled correctly. BTW, SMALL leaks will not cause Oil loss. TOO MUCH 134a is as bad as too little. Too much and the system will not cool correctly just like too little. A TEST for posters. HOW much 134a(lbs) do you think a average Diesel RV motorhome takes? Doug

A diesel pusher about 3-4 lbs

Trick question. For most Diesels 2.0 to 4.25 lbs. BUT Some large diesels(usually Spartan) built after 2014 from 6 to 8 lbs. Doug

[dougrainer]

rgatijnet1 wrote:

dougrainer wrote:

Ivylog wrote:

crasster wrote:
Really - while you can DIY recharge, it is BEST if you can put the system under a deep vacuum then charge. It's the proper way to get all the air out so there is more pure 134a.

Really, How is air going to get into a system that is still cooling, but not as cold as normal... is still pressurized and has enough freon in the system to work somewhat? Even while working the low pressure side will have 60+ psi in it... how is air going to get in???

Bingo. HOW can air get into a pressurized system? IF the system has been open to the atmosphere, then yes, find the leak, then Vacuum and charge. Vacuum can also let you know if the system has a large leak. Small leaks that happen under pressure, a Vacuum test rarely is accurate. Now, HOW is a novice supposed to know how much 134a to install? Unless you have your gauges connected and do a digital temp at closest outlet to the evaporator, you will have a hard time getting it filled correctly. BTW, SMALL leaks will not cause Oil loss. TOO MUCH 134a is as bad as too little. Too much and the system will not cool correctly just like too little. A TEST for posters. HOW much 134a(lbs) do you think a average Diesel RV motorhome takes? Doug

If the system is still pressurized then who cares how much freon the system holds? All you really need is a thermometer. Placed in the outlet of one of the ducts, add freon slowly until the temperature drops to it's lowest and starts to go back up. As soon as that happens, you stop. You are right, too much is as bad as not enough so you add for the lowest temp reading.
Now this is not scientific and is not how a tech would do it but for a NOVICE, it will work just fine and probably save them a lot of money.

This is true. You watch the temp gauge and when the temp stops at a certain temp, you wait until it raises a degree or 2. Then STOP the fill. BUT, a lot of novices will not do that and will overfill. Doug

[chuckftboy]

I have been in the HVAC industry for a little over 45 years and I have to say, this has been a fun post to read. Thanks everyone.

[Gjac]

You can look for leaks yourself. when I had this problem I checked all the fittings and hoses, I noticed an oily substance on a switch, mine was a trinary switch some are binary they heve either 2 or 3 wires going to the switch. I changed out the switch and added a can or two of 134 and it has been good for about 6 years now. I think the kit I bought at Adv Auto and it came with a pressure gauge, a can of 134, a can of 134 with dye and a ultraviolet light pen all for $20 on sale. I wiped every thing down and saw no leaks with the ultraviolet light.