Dash AC

[Tarheel 62]

i've been reading the discussion items for some time now and find I have a lot in common with most. I've noticed a lot of comments/questions concering the dash AC. Usually the answer has come down to the Evans control valve. Is it possible that in a lot of cases it was the compressor attaining 400 psi or more? That seems to be my problem. I have a 2001 Damon Intruder and the AC has never worked right in my opinion. I convinced myself that RV ACs didn't do a good cooling job. Then I read the Workhorse chasis guide for 2006 and learned a lot. Especially the letter to certain dealers concerning the AC problems, but not to RV owners. In my case I finally took the RV in to be serviced. They put about 2 lbs of 134 into system, found/replaced a stuck strater (sp) valve, and a R-12 conector on the high pressure side. As soon as the engine warmed up to normal temp the compressor head pressure topped 400 psi and no more cool air. After a short trip, the system was checked again and found low on 134. No leaks were found except the high pressure is blowing freon through the connections. Also, cylinders 5 & 7 are misfiring. Any connections? My original complaint with Workhorse, a couple years ago, was that the engine fan ran excessively. I was told that it was performing within limits, but no more test were conducted as to why the fan ran so much. Could the problems be caused by a lack of air flow? The most imediate question is what to do about the high pressure and lack of AC. I have an appt with the nearest Workhorse Service Center this Wed. I would like to know what you guys think. Thanks

[Tarheel 62]

i've been reading the discussion items for some time now and find I have a lot in common with most. I've noticed a lot of comments/questions concering the dash AC. Usually the answer has come down to the Evans control valve. Is it possible that in a lot of cases it was the compressor attaining 400 psi or more? That seems to be my problem. I have a 2001 Damon Intruder and the AC has never worked right in my opinion. I convinced myself that RV ACs didn't do a good cooling job. Then I read the Workhorse chasis guide for 2006 and learned a lot. Especially the letter to certain dealers concerning the AC problems, but not to RV owners. In my case I finally took the RV in to be serviced. They put about 2 lbs of 134 into system, found/replaced a stuck strater (sp) valve, and a R-12 conector on the high pressure side. As soon as the engine warmed up to normal temp the compressor head pressure topped 400 psi and no more cool air. After a short trip, the system was checked again and found low on 134. No leaks were found except the high pressure is blowing freon through the connections. Also, cylinders 5 & 7 are misfiring. Any connections? My original complaint with Workhorse, a couple years ago, was that the engine fan ran excessively. I was told that it was performing within limits, but no more test were conducted as to why the fan ran so much. Could the problems be caused by a lack of air flow? The most imediate question is what to do about the high pressure and lack of AC. I have an appt with the nearest Workhorse Service Center this Wed. I would like to know what you guys think. Thanks

[Full-Timers]

With all your symptoms, I would say you are not getting enough airflow through the "cool pack"� or radiator. More airflow through the cool pack will increase the efficiency of your air conditioner, make your fans run less and help with the #5 and 7 plug wire burning issue. Make sure your air dam is in tact. Replacing the #5 and 7 plug wires will fix the miss but you have to address the reason the wires burnt. A vent kit will help. You didn't mention what the motorhome manufacturer or year was but I learned first hand that Rexhall has a problem with airflow and grill design.

[Tarheel 62]

Thank for the info. I have a 2001 Damon Intruder 350, W-22 chasis. The plug wires for 5 & 7 check ok as do the plugs themseles. I have thought about a cooling kit, but haven't done anything yet. I also wonder about making the AC fans run all the time the AC is on or replacing the condensor with a larger one.

[FreshAir]

Help me out please. I have always been a little confused, to put it mildly, about the air dam and the 5,7 plug wire heat problem. First, I agree that as much air as possible should be shunted through the radiator for correct engine and AC operation but doesn't that limit cooler ambient air flow getting to the plug area of the engine than if you have ALL the air going thru the radiator? It seems to me that outside ambient air being at say 90 F is cooler than what's leaving the radiator after passing thru maybe the 190 F radiator core temps. Seems to me that some outside ambient air would cool the spark area better than the air passing thru the radiator? Somebody set me straight please. Been a monkey on my back as I just don't get it. Seems to me that some outside air by passing the radiator core should help cool the plug area better than the air coming directly from the radiator? Wouldn't it be better to let some air escape around the air dam to help cool the plug area???
Obviously I'm not a design engineer. Thank's,
Pat

[edgray]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I also wonder about making the AC fans run all the time the AC is on.... </div></BLOCKQUOTE>

The electrically operated fans SHOULD be ON at ALL times when the engine is at operating temperature AND the A/C compressor is running. ED

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Pat & Denise:
Help me out please. I have always been a little confused, to put it mildly, about the air dam and the 5,7 plug wire heat problem. </div></BLOCKQUOTE>Pat, The cooling system of the engine itself is the most critical component that needs to be considered first. Getting the most amount of air through the condenser, cooler and radiator assures that the engine runs cool. If the engine runs cool then the peripherals will be less likely to over heat.

Assuring that the majority of air passing through the front fascia is channeled to the radiator by means of air dams fitted to the top and sides of the cooling system is essential.

Other than the WCC Cold Air Kit which directs relief at a focused point the kit is not typically needed. Only a few degrees difference of cooling are needed. Bleeding air around the cool pack to cool spark plug wires doesn't work because the engine coolant does not shed enough heat. Actually the hot air passing through the cool pack plays a part in reducing the extreme heat that occurs at the exhaust manifolds on most motor coaches and properly designed air flow characteristics in the engine house does the rest.

Some motorhomes like mine for instance have never exhibited plug wire melt down now approaching 60,000 miles. The design and parts used are adequate to the task. The only variable is the engine enclosure which WCC has little control over other than to advise the OEM what the cooling requirements are.

[Full-Timers]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Pat & Denise:
Help me out please. I have always been a little confused, to put it mildly, about the air dam and the 5,7 plug wire heat problem. First, I agree that as much air as possible should be shunted through the radiator for correct engine and AC operation but doesn't that limit cooler ambient air flow getting to the plug area of the engine than if you have ALL the air going thru the radiator? It seems to me that outside ambient air being at say 90 F is cooler than what's leaving the radiator after passing thru maybe the 190 F radiator core temps. Seems to me that some outside ambient air would cool the spark area better than the air passing thru the radiator? Somebody set me straight please. Been a monkey on my back as I just don't get it. Seems to me that some outside air by passing the radiator core should help cool the plug area better than the air coming directly from the radiator? Wouldn't it be better to let some air escape around the air dam to help cool the plug area???
Obviously I'm not a design engineer. Thank's,
Pat </div></BLOCKQUOTE>I understand your theory about warmed air to the plug area. However by directing the air through the radiator you are also directing more air to the plug area rather than around and away from the engine.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DriVer: Bleeding air around the cool pack to cool spark plug wires doesn't work because the engine coolant does not shed enough heat. </div></BLOCKQUOTE> I agree that BLEEDING air around the cool pack is not a good idea but adding the vent kit scoops in my grill and directing some of the air directly to my #5 plug fixed my problem.

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Full-Timers:
I agree that BLEEDING air around the cool pack is not a good idea but adding the vent kit scoops in my grill and directing some of the air directly to my #5 plug fixed my problem. </div></BLOCKQUOTE>This is directing air flow for a purpose which works very well in 95% of the cases where it's needed. Fortunately the majority of owners do not need the cold air kit.

[M&EM]

from Tarheel62
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Could the problems be caused by a lack of air flow? The most imediate question is what to do about the high pressure and lack of AC. I have an appt with the nearest Workhorse Service Center this Wed. I would like to know what you guys think. Thanks </div></BLOCKQUOTE>

I would guess that:
1) too much 134a has been added.
2) air and /or moisture got in the system,
3) expansion valve, dryer system is plugged up resulting in limited or no cooling.

The compressor is supposed to have a high pressure shutoff switch limit around 425 psi.

[John-D]

One suggested edit to the original post, then a comment: if your rig is a 2001 they did not replace an R-12 anything, it's R-134A They have not produced R-12 systems in over a decade. R-12 is no longer produced and the only R-12 sold is re-claimed from older units.

Now the comment:

My first big trip the dash air quit on my rig, Wheelers RV in Las Vegas told me it was a low pressure cut out switch (I knew better than that since I'd done my own limited diagnosis and the compressor was running, if it had been the cut out switch the compressor would NOT have been running)

IT was the expansion valve.

In may (in fact one year ago TODAY!) I visited Damon Plant 12 due to another issue (My rig came with the optional self-removing windshield, i had them remove that option since I did not order it) they replaced the expansion valve.

Very nice AC tech there at Damon, he's an RVer himself, at the time he had a 2006 Intruder he was deluxing during his off hours.

Oh yes, they did a very good job of disabling the self-removing option too. Great folks there at Plant 12. And their scheduler worked with me so my total millage for the trip to their plant was sixty miles round trip (next to nothing as I measure millage.)

[adj]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by edgray:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I also wonder about making the AC fans run all the time the AC is on.... </div></BLOCKQUOTE>

The electrically operated fans SHOULD be ON at ALL times when the engine is at operating temperature AND the A/C compressor is running. ED </div></BLOCKQUOTE>
I'm confused, The fans in my rig operate intermittently depending on the strain and temperature in the engine. I've never experienced the the fans automatically coming on just because I turn the A/C on.

[edgray]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I'm confused, The fans in my rig operate intermittently depending on the strain and temperature in the engine </div></BLOCKQUOTE>
There is a lot of confusion about these fans. The intermitent "roar" you sometimes hear is the clutch operated large fan behing the radiator. IT is the one which cycles on and off with engine coolant temps. The two small electric driven fans out in front of the A/C condensor are too quite to be heard inside the coach and SHOULD always be running IF the A/C compressor is ON and the engine up to operating temp. ED

[adj]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by edgray:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I'm confused, The fans in my rig operate intermittently depending on the strain and temperature in the engine </div></BLOCKQUOTE>
There is a lot of confusion about these fans. The intermitent "roar" you sometimes hear is the clutch operated large fan behing the radiator. IT is the one which cycles on and off with engine coolant temps. The two small electric driven fans out in front of the A/C condensor are too quite to be heard inside the coach and SHOULD always be running IF the A/C compressor is ON and the engine up to operating temp. ED </div></BLOCKQUOTE>

Thanks edgray for clearing that up.