Question on bus AC

[Jerry32]

I decided to check out the AC on my bus as it has been hot here in the west. I fired up the the engine and turned on the air and everything worked. However when I was returning from SC The AC quit on me and I don't see a problem with  it now also when I looked at the guage connections they are the type that 134 conversions use, is this standard or did someone convert to 134 and no tag. Since it was working I didn't take any readins of the high and low pressure. What are things that might stop the AC from working? Jerry

[Busted Knuckle]

Hey Jerry,
It is commonly found that folks change over to 134 with out "tagging it" yer lucky the even put the 134 fittings on it as a lot of "clowns " just use R12 gauges with the 134 leaving no clue that it's been changed!

Now lets start with the easy stuff and work our way up! 1st off does the condenser fan come on when you flip the switch up for A/C? If not it should! So let's figure that out and go from there! If the condenser fan comes on, undue the duez fasteners and open the condenser door. Don't hold it open long while it's on, but look for the sight glass in the accumulator tank. Most of the time there will be 1-3 orange or red beads that float to show you the level of the freon. If they are or you can see the liquid itself half way or more in the bottom sight glass. Then your freon is ok. First check these things out and we'll start trouble shooting from there! HTH    BK 

[Jerry32]

The condenser fan was working with my short test but I found the brush covers removed might be a clue. Might be a problem with the blower motor. I remember coming back that the air worked for a while then quit and maybe the motor cuts out when it get hot. I will have to check that thanks Jerry

[Busted Knuckle]

The condenser fan was working with my short test but I found the brush covers removed might be a clue. Might be a problem with the blower motor. I remember coming back that the air worked for a while then quit and maybe the motor cuts out when it get hot. I will have to check that thanks Jerry

OK what ya need to do is make sure the blower has good brushes! Now not that I condone it or even like it soooo many times I've seen motors with no brush covers! (and they seem to work ok, but I'd still prefer they were covered if they were mine!). Then after you have made sure ya got good brushes, turn the A/C on again and make sure the fan is pulling air thru the condenser, and out thru the bottom of the compartment! (trust me it'll blow a clean spot there if it is) if that fan isn't working the A/C won't stay on long as it'll get too hot and cause too high of pressure which will cause the pressure switch to shut off the rest of it! Once you know the condenser fan is working it's time to check the compresser! On yours you should be able to have someone turn the A/C on wile you watch the compresser pulley, you should see the center freewheel until they turn it on then as the clutch engages you should see the center start spinning as well! Let us know!
  BK 

[Jerry32]

I checked the clutch before and it is working ok. I got the condenser bay open and watched the site glasses and seen no bubbles. The condenser fan turns up as narmal. wow that condenser gets hot in a hurry on these 100 deg days. the blower was blowing lots of cool air and I don't know why it would have conked out on my cross country trip but seems great now. there was some rain on the cross country and maybe with those covers off the condenser blower motor there was a problem. I will have to find some screws to put those covers back on Jerry

[Busted Knuckle]

OK my guess is to try an add some freon!
  BK 

[Nick Badame Refrig/ACC]

Hi Jerry,

Just to add to BK's info,  A clear sight glass may also mean that the system is at full capacity of freon.

Look at the suction line [fat copper pipe] at the compressor, is should be cold and sweating... if so the refrigeration system is working fine and the trouble is elsewhere.

I would then start looking at the curcuit breakers and feel if your A/C switch on the dash is hot! You could be overdrawling on current and tripping the breaker.

Next I would amp out the blower motors to see if they are drawling too much current. Check the tags on the motors for the proper amp draw.

Let us know what you find
Nick-

[Busted Knuckle]

Hi Jerry,

Just to add to BK's info,  A clear sight glass may also mean that the system is at full capacity of freon.

Look at the suction line [fat copper pipe] at the compressor, is should be cold and sweating... if so the refrigeration system is working fine and the trouble is elsewhere.

I would then start looking at the curcuit breakers and feel if your A/C switch on the dash is hot! You could be overdrawling on current and tripping the breaker.

Next I would amp out the blower motors to see if they are drawling too much current. Check the tags on the motors for the proper amp draw.

Let us know what you find
Nick-     

OK Jerry now we got the real A/C expert helping us! Won't be long til yer cool as a cucmber! LOL!
Thanks Nick, I was wondering when someone who knew more 'bout this stuff than me was gonna jump in!
  BK 

[Jerry32]

I am going to take a short trip in a couple of weeks going with the camping club to Hell's Canyon for four days and I will find out if it will stay working or not  I believe the freon is full as on my last time I went out an run the AC it was cooling good for the outside air temp being 100 degrees. The only thing I noticed that when I turned on the AC switch the first time it did not start. I then turned it off and on again and the unit started so may have a bad relay so will have to look at the electrical and see if there is a diagram for that. Jerry

[mc8 tin tent]

Jerry
You may want to valve out the bus heaters (with 100+ ambient temps an a heater valve sticking open it could become warm but dry)
Good luck
Dwayne

[niles500]

Jerry - some systems have a compressor delay of up to 2 minutes - was the fan running and just not cool for a minute or 2?

[Jerry32]

All fans started on the second try and maybe that is why things didn't start on the first try. I have been in the proccess of puting things together enough to be able to use the bus for some trips this year. I figure I can do finish work or rebuilding as I go along. Next is a heat pump to put in for cooling when the coach is stopped or as backup on the road. Jerry