Dash AC-Charge Ports at Front of 2004 Signature

[trailmug]

Bingo, 4475/4756 is for use with the Cummins water pump pulley. Only notable difference between those two is the electrical connector, which I had to swap.

[Carnac]

I replaced both the receiver/drier AND the expansion valve on my system.

I found that I had lots of high side pressure and low low side pressure - so the compressor was good, but blockage in the system. I was getting 5-10 psi on the low side and 225+ psi on the high side (outside air temp around 100 degrees). So, I was getting blockage.

Mine had a good bit of crud in both the receiver/drier and the expansion valve. Neither are very expensive - worth replacing if you have the system apart. I think my expansion valve was less than $20.

My system is OK now - could be better. I am going to spend some time cleaning the condenser coils on the radiator side and make sure that the fan is running good.

I'll know more when I have the unit out and running for a while at highway speeds.

Static, I was getting about 52-55 degree temperatures at the dash vent. I was hoping to see around 48 degrees.

Jim 

[Ivan K]

You may also want to see if it is cooling outside air or recycling what's already cooled. Closing the outside fresh air intake helped us a lot while driving.

[Gary Cole]

Jim my evaporator thermostat opens at 48 degrees as measured at the lower end of the evaporator tube as it exits the case. Never going to get cold air at that high setting. Bought a thermostat with an adjustable set point. Plan on installing it this weekend. Think it will help a lot. That high setting also tends to cycle the compressor too frequently. My compressor only runs briefly before it disengages.

Edited August 18, 2022 by Gary Cole

[Lee Smith]

My dash AC is now fixed and working fine. I replaced the dryer/filter and the compressor. While I had the compressor off, I replaced the tensioner pully and added a new belt.

First, I drained the new compressor of its preloaded oil and then added 6 oz PAG 100 back in accordance with the Sanden compressor manual instructions. Second, I installed the new compressor. Third, I vacuumed the system for two hours. Finally, I started the engine, turned on the AC and charged the system with 60 oz of R134A. 

It seems like someone had previously removed the compressor low and high side hoses but neglected to put the correct seals back on and also over tightened so much they were completely flattened. One of the seals was normal black rubber instead of the green type as required for R134A. There were major signs of compressor oil leakage right at the connection points. The old compressor had no oil at all. There were also bad seals at the front of the RV where the dryer filter was. The new filter/dryer came with new seals.
I could not have done this work without all of the great advice from everyone on the forum.
Thank you very much.

Here are a couple of pictures at the engine for the new compressor and the new tensioner pully:

Unfortunately, the bigger problem is the need for a larger garage:

I will be working on this at my first opportunity. However, I will need to move the RV so my wife can use the garage again.
In closing, I wish to again express my great appreciation for this forum.
Bill D's Monacoers is the best.
 

[TimSpencer]

On 8/18/2022 at 5:24 PM, Carnac said:

I replaced both the receiver/drier AND the expansion valve on my system.

I found that I had lots of high side pressure and low low side pressure - so the compressor was good, but blockage in the system. I was getting 5-10 psi on the low side and 225+ psi on the high side (outside air temp around 100 degrees). So, I was getting blockage.

Mine had a good bit of crud in both the receiver/drier and the expansion valve. Neither are very expensive - worth replacing if you have the system apart. I think my expansion valve was less than $20.

My system is OK now - could be better. I am going to spend some time cleaning the condenser coils on the radiator side and make sure that the fan is running good.

I'll know more when I have the unit out and running for a while at highway speeds.

Static, I was getting about 52-55 degree temperatures at the dash vent. I was hoping to see around 48 degrees.

Jim 

Restrictions are likely to be in the receiver/drier(easier to change most of the time) or expansion valve(under dash never fun). Many times you will see frost on the line/ fitting on the leaving side of the drier. Any of the synthetic compressor oils used with R134a refrigerant will clean out the inside piping as it passes through the system. Hopefully collecting in the drier rather than the expansion valve. Have as clean a system as possible before charging is best. There are system flushing agents you use to clean piping and coils before charging. 

Edited August 20, 2022 by TimSpencer

[TimSpencer]

Everyone has now graduated to HVAC specialists. Great job on both coaches. 

[Daryl Ammons]

2009 Monaco Dynasty 43’.  Does anyone know where I might find the Freon refrigerate capacity for the Chassis AC on my Dynasty?

[Tom Cherry]

Yes

 

It is called out in your Manual in the back.  Look there.

You can also start to use the search Function.  That is preferred as we have too many subjects that are related and we have to do housekeeping to clean them up.

NOTE.  I searched for Refrigerant in the TOPICS section and found at least a dozen posts.  I am merging or combining this one into the one that looks the most complete.

Thanks, in advance for searching before posting....,

[Daryl Ammons]

11 minutes ago, Tom Cherry said:

Yes

 

It is called out in your Manual in the back.  Look there.

You can also start to use the search Function.  That is preferred as we have too many subjects that are related and we have to do housekeeping to clean them up.

NOTE.  I searched for Refrigerant in the TOPICS section and found at least a dozen posts.  I am merging or combining this one into the one that looks the most complete.

Thanks, in advance for searching before posting....,

Thanks Tom,  I tied the search but must not have done it properly or put in the correct words.  My bad will try to do better in future.  Appreciate this site and the info you guys share.  I know it must take a lot of work to keep it going.

Thanks Again,

Daryl

[vito.a]

Our 2004 Signature uses a Sanden U4756 compressor on a Cummins ISX.  It has a serpentine belt pulley.  

I think Monaco added the A/C compressors to the engines.  

Our dryer is a 4 Seasons 33276.  

 

[Tom Cherry]

1 hour ago, Daryl Ammons said:

Thanks Tom,  I tied the search but must not have done it properly or put in the correct words.  My bad will try to do better in future.  Appreciate this site and the info you guys share.  I know it must take a lot of work to keep it going.

Thanks Again,

Daryl

The generic search might just be within a topic.  Used the drop down tool bar and select topics.  For things like prints for each year, use “wiring diagram”. That works.  You manual does have info on the refrigerant.  Most folks “top off” and don’t pull a vacuum or drain the system.  Usually a small leak will take two cans .  Mine needs that about every 2 - 3 years.  There are som pressure charts in the posts….maybe this one.  Forget about trying to get a certain center vent temperature.  You need the interior of the Coach cooled down a bit.  Most folks drive into a shop and it is hot outside and the front AC SYSTEM will not be cooled down.  No way you are ever gonna get 45 - 50 DF air out of it.

My rule of thumb.  NOTE….Odds are your manual is wrong.  The AC compressor comes on in the bilevel or the up and down arrow position to the tight of OFF.  The vent on the next side is pure vent. No compressor.  Foot has no compressor.  Rest do.  
 

i always use max AC.  FOR heat.  Turn the control to MAX HEAT (RED).  Then on moderate days use the vent and foot.  On really cold days, use max AC.  That blocks off the incoming cold air.  Most folks do this.

Final tip.  For 85 DF or hotter days, run the Genny and one or two AC.  Don’t know if you have a DUMP position in the ceiling where you can open up a grill and dump cold air.  The Genny burns a whole lot less fuel than running the AC on max.  Most economical and your passengers stay cooler.  I use a 10” oscillation fan between the drivers and passenger seats to circulate air to me and DW.

GOOD LUCK

[trailmug]

3 hours ago, Tom Cherry said:

The generic search might just be within a topic.  Used the drop down tool bar and select topics.  For things like prints for each year, use “wiring diagram”. That works.  You manual does have info on the refrigerant.  Most folks “top off” and don’t pull a vacuum or drain the system.  Usually a small leak will take two cans .  Mine needs that about every 2 - 3 years.  There are som pressure charts in the posts….maybe this one.  Forget about trying to get a certain center vent temperature.  You need the interior of the Coach cooled down a bit.  Most folks drive into a shop and it is hot outside and the front AC SYSTEM will not be cooled down.  No way you are ever gonna get 45 - 50 DF air out of it.

My rule of thumb.  NOTE….Odds are your manual is wrong.  The AC compressor comes on in the bilevel or the up and down arrow position to the tight of OFF.  The vent on the next side is pure vent. No compressor.  Foot has no compressor.  Rest do.  
 

i always use max AC.  FOR heat.  Turn the control to MAX HEAT (RED).  Then on moderate days use the vent and foot.  On really cold days, use max AC.  That blocks off the incoming cold air.  Most folks do this.

Final tip.  For 85 DF or hotter days, run the Genny and one or two AC.  Don’t know if you have a DUMP position in the ceiling where you can open up a grill and dump cold air.  The Genny burns a whole lot less fuel than running the AC on max.  Most economical and your passengers stay cooler.  I use a 10” oscillation fan between the drivers and passenger seats to circulate air to me and DW.

GOOD LUCK

Along these lines, when parking, turn the system to OFF or MAX for several seconds before shutting the engine off, or the outside air damper remains open (at least on ours). More stuff for the checklist.. these things are a lot like airplanes 🙂

Sanden compressors are supposed to use 5HP or less.. I think most of the summer fuel burn comes from the higher demands on the engine fan.. unless your engine fan doubles as your condenser fan, and then that makes total sense.

[Rikadoo]

Soooooo please, knowing about ac systems can be a challange!!! That all ac systems are of the same design, oil travels with freon. That said when a system is “FULLY” charged the oil travels with the freon, NOW, as a system drops in freon the oil which was trying to flow ONLY was able to travelfor as long as the freon supply could take it. When i get a … low system, i first recover what is in the system, i then pull the system into a vacume, add 2oz of dye, then charge to spec, turn system on, let run 20 min later, measure high side / low side… then look for “wet spots” if nothing shows the oil is not invisibul, if its leaking, you will see accumulation. My personal favorite is to drive it a couple days using the ac, get your nose to smell whats comming out of the ducts, does it smell good or ??? If it smells ??? Then what I do is to drill the evaporator case, ( know where your drilling) then use a borescope an look at the evaporator, if i see “the wet spot” i know to replace whats leaking! And quit guessing what it might or “could” be i apologise for being blunt, so many want it to be a mystery, an times it can be, however if your freon has had dye mixed with it it, you CAN find the leak… but dont not talk about the  elephant in the room, you need to put eyes on your “hidden” componet the evaporator

[TimSpencer]

16 hours ago, Rikadoo said:

Soooooo please, knowing about ac systems can be a challange!!! That all ac systems are of the same design, oil travels with freon. That said when a system is “FULLY” charged the oil travels with the freon, NOW, as a system drops in freon the oil which was trying to flow ONLY was able to travelfor as long as the freon supply could take it. When i get a … low system, i first recover what is in the system, i then pull the system into a vacume, add 2oz of dye, then charge to spec, turn system on, let run 20 min later, measure high side / low side… then look for “wet spots” if nothing shows the oil is not invisibul, if its leaking, you will see accumulation. My personal favorite is to drive it a couple days using the ac, get your nose to smell whats comming out of the ducts, does it smell good or ??? If it smells ??? Then what I do is to drill the evaporator case, ( know where your drilling) then use a borescope an look at the evaporator, if i see “the wet spot” i know to replace whats leaking! And quit guessing what it might or “could” be i apologise for being blunt, so many want it to be a mystery, an times it can be, however if your freon has had dye mixed with it it, you CAN find the leak… but dont not talk about the  elephant in the room, you need to put eyes on your “hidden” componet the evaporator

I’m not a fan of dye but searching all portions of the system is vital. By any means. Dye, leak detection meter, etc. 

[Gary Cole]

If you are going to top off a system without drawing a vacuum and you know the recommended charge then you can bleed off the existing charge to within a few lbs of positive pressure and then add the recommended charge. A slight overcharge to ensure that the evaporator is flooded with freon for maximum cooling  is preferable to an undercharge. The accumulator and  hose length will ensure that no liquid freon reaches the compressor so long as one exercises discretion. You can use the frost on the fittings as a guide to how much freon you have in the system.

[trailmug]

If using dye, make absolutely certain it's compatible with PAG.. mineral oil dye will do this (I believe what happened to mine):

Edited September 29, 2022 by trailmug

[Rikadoo]

Looking at that reed plate, looks like the oil overheated an burned. When that system was running what was the pressure on the high side? 

[TimSpencer]

17 hours ago, Gary Cole said:

If you are going to top off a system without drawing a vacuum and you know the recommended charge then you can bleed off the existing charge to within a few lbs of positive pressure and then add the recommended charge. A slight overcharge to ensure that the evaporator is flooded with freon for maximum cooling  is preferable to an undercharge. The accumulator and  hose length will ensure that no liquid freon reaches the compressor so long as one exercises discretion. You can use the frost on the fittings as a guide to how much freon you have in the system.

Not the best way. You can look at system pressures and temp to get a better idea of the charge on any refrigeration system. “Bleeding” refrigerant is just a waste of expensive refrigerant. 

1 hour ago, trailmug said:

If using dye, make absolutely certain it's compatible with PAG.. mineral oil dye will do this (I believe what happened to mine):

Definitely looks overheated and contaminated for sure. Kind of the chicken or the egg. Did heat deteriorate the oil first or did the dye break the oil down. More likely high temp/pressure or low refrigerant charge(from leak) oil not returning from evaporator and compressor running out of oil and burning the small amount of oil left(my first guess)

[trailmug]

This one's a picture from the Sanden failure modes analysis PDF, though mine looked rather similar

[Guest Ray Davis]

Regarding compressor heat, our coaches w/ side radiators can be inclined to develop excessive heat when idling or stop & go.  The fan may not turn fast enough to move sufficient air, there was a modification to speed it up some.  I think Chuck B had it done on his 04 Windsor, maybe he will chime in.   Also, on some coaches the condenser coil is cooled by a 12v elect fan, that fan may fail.

[Tom Cherry]

On 9/29/2022 at 11:09 AM, Ray Davis said:

Regarding compressor heat, our coaches w/ side radiators can be inclined to develop excessive heat when idling or stop & go.  The fan may not turn fast enough to move sufficient air, there was a modification to speed it up some.  I think Chuck B had it done on his 04 Windsor, maybe he will chime in.   Also, on some coaches the condenser coil is cooled by a 12v elect fan, that fan may fail.

The GENERIC way to speed up IDLE is to turn on the CRUISE and then push the SET button (I think)....maybe Resume....it is in the manual.  That kicks up the idle.  Maybe not fast enough, but I have used this for REGEN when I had to stop.

Frank McElroy corrected the misinformation about REGEN in a subsequent post.  
Thanks.  

This assumes that the cruise is part of the VIP wheel.

 

[Guest Ray Davis]

1 hour ago, Tom Cherry said:

The GENERIC way to speed up IDLE is to turn on the CRUISE and then push the SET button (I think)....maybe Resume....it is in the manual.  That kicks up the idle.  Maybe not fast enough, but I have used this for REGEN when I had to stop.

This assumes that the cruise is part of the VIP wheel.

 

That's right, I use the cruise control especially when I need to build air pressure.  I have an idle speed push button on the dash, but it takes repeated pushes to get up to speed where the cruise is instantaneous on & off.  At my age I don't want to waste time pushing buttons. LOL

[Gary Cole]

3 hours ago, TimSpencer said:

Not the best way. You can look at system pressures and temp to get a better idea of the charge on any refrigeration system. “Bleeding” refrigerant is just a waste of expensive refrigerant. 

I agree its not the best way. However it is a solution for the casual do it yourselfer. Due to the excessive pressure drop in our systems there is not a direct correlation between temperature and pressure. Particularly when using the gauge scales. This seems to confuse many. Judging from the comments on this topic the tendency is to grossly overfill their systems. 

I have wondered if the poor performance of my system might not be caused in part by the inability of the compressor to keep the evaporator flooded at high ambient temperatures due to the pressure drop. I think the hoses should have been one or 2 sizes larger given the length. Please correct me if my premise is incorrect. I'm only a casual do it yourselfer myself. 

[TimSpencer]

Lots of variables. Easy button remove refrigerant then add factory recommended charge. Check pressures and temps and sight glass if equipped. Add refrigerant to clear glass. If everything else in the system is working then you should be good and it will be cooling properly. If pressures are not where they should be then further troubleshooting will be needed. I would guess the A/C system designer got it close enough to work correctly, nothing is perfect always some compromise