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KATOOM

Can I cover the AC dryer to protect from exhaust heat?

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Posted (edited)

I've always pondered why the AC dryer/accumulator hanging on the firewall is so close to the exhaust.  Logic tells me that this wouldn't be a great design when you're asking the condenser to cool the freon down so it can return into the evaporator...only to have it pass right next to a 800-900* exhaust along its way.  Seems kinda counter productive... :think:

 

Anyways, I had some extra heat insulation material for protecting things from direct heat and thought, why not wrap it around the dryer/accumulator to better protect it from the hot exhaust.  Is there something I'm missing?  Would this be a problem I'm unaware of?  Would this even help?  I've heard of people wrapping their AC lines with insulation material to help cool the AC, but not the dryer.  Any insight would be helpful.  Thanks. :thumb1:

Turbo blanket.jpg

Edited by KATOOM

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Heat always moves to cold, that's physics.  So any part of the low pressure side of the A/C system from the expansion valve to the evaporator and accumulator is colder than their surroundings and will absorb the heat.  This is extra heat that has to be removed from the system through the condenser.  These 16 year old condensers aren't as efficient as when new so the system could use that added help of insulating the low pressure pipes, hoses and accumulator.   

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Posted (edited)

Still you have to have a condition that is creating massive heat. My average highway EGT is 450 to 600*F tops flat ground depending on road speed. Then with 55 to 65 MPH air blowing through the grill I don't think the heat gets a lot of time to soak into the accumulator can. Creately my A/C is so damn cold you typically can stand the coldest setting the cab temperature can drop well below 70*F and colder while moving at highway speed. 

 

Now someone towing day in and out I can see this mod.

 

Now traffic and stop light different story this condition I don't think even heat wrap will do much good being the fan most likely won't lock up enough to move air fast enough to keep the condenser and the under hood temperatures down. It's a battle no matter how you slice it. 

Edited by Mopar1973Man

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Thanks for the perspective guys...  If it helps the AC at all then great.  But, my main concern at this point is if there's any harm which can come of the AC system from wrapping the dryer. :think:

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Posted (edited)
8 minutes ago, KATOOM said:

But, my main concern at this point is if there's any harm which can come of the AC system from wrapping the dryer. :think:

 

 No harm will happen. 

 

Like I wrapped my orifice tube to increase A/C performance since its the source of the cold for the cab. The accumulator is after the evaporator and any heat is sent to the condenser out front like @IBMobile said. 

Edited by Mopar1973Man

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Well I guess I should have done more of my own homework before throwing this question out there :duh:.....because now I understand that what I just covered up is just the accumulator NOT the dryer.  And since the accumulator is on the low pressure side, there is no point in trying to protect it from heat since all I would be doing is potentially reducing the vaporization of the freon as its moving towards the compressor.  No need to potentially increase the chances of slugging.  My bad for being stupid.  So wrapping removed... :thumb1:

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Posted (edited)
On 6/19/2018 at 12:03 PM, KATOOM said:

Well I guess I should have done more of my own homework before throwing this question out there :duh:.....because now I understand that what I just covered up is just the accumulator NOT the dryer.  And since the accumulator is on the low pressure side, there is no point in trying to protect it from heat since all I would be doing is potentially reducing the vaporization of the freon as its moving towards the compressor.  No need to potentially increase the chances of slugging.  My bad for being stupid.  So wrapping removed... :thumb1:

Exactly correct on using low pressure side insulation. Heating causes refrigerant to turn into gaseous vapor state. Cooling refrigerant turns it into liquid state. Evaporator heats refrigerant to vapor, condenser cools refrigerant into liquid.

 

When doing the DIY charging on the low pressure service port never turn the refrigerant can upside down with the compressor engaged unless a damaged compressor is wanted. A can of refrigerant right side up submerged in a bucket of warm water works better. I've changed a bunch of compressors from the DIY super truckers trying to charge their own A/C and thinking turning the can upside down causes the system to accept the refrigerant faster. It's very easy to spot liquid refrigerant damage to a compressor. The high side readings are erratic a jumpy.

 

I pulled 6 pounds of refrigerant out of Freightliner M2 today that had a damaged compressor from a DIY'er that made the can mistake. System capacity is 3.25 pounds.

 

1 pound equals 16 ounces. Be careful about over charging. 1 pound will be the same pressure as 3 pounds in a system not turned on. You can not charge MVAC / HVAC by pressure readings, at least that's what the EPA says when doing certifications to service systems. Pressure readings are to only diagnose system components. You need High and Low side pressure readings to properly diagnose air conditioning system.

Edited by 04Mach1
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04Mach1, your input is greatly appreciated, but I have to say I'm not completely sure I understand.  Are you saying covering the acuumulator was good or bad?

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6 minutes ago, 04Mach1 said:

Bad - the added heat from the exhaust will keep the refrigerant in a gaseous / vapor state just as your compressor likes it.

 Once the refrigerant is in a gaseous state the only way it can go back to a liquid is be compressed and sent through the condenser.  A properly filled A/C system will not cause slugging.  Over filled or filling the system with an inverted can will cause slugging. 

 

Insulating the piping after the orifice tube and before the evaporator is no problem.  After the evaporator some auto manufacturer choose to insulate the accumulator.  

 

  GM has done it with this products like this.

https://www.ebay.com/p/A-C-Accumulator-Insulator-ACDelco-GM-Original-Equipment-15-10614/79416292?iid=282964073381&_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D52475%26meid%3D84e53c92765446a885aca61308b093e9%26pid%3D100005%26rk%3D6%26rkt%3D12%26sd%3D161767073957%26itm%3D282964073381&_trksid=p2047675.c100005.m1851

 

Ford did it with a spray on insulation but it caused the accumulator made of steel to rust out, there was no way for the condensation to evaporate.  Now they are made of aluminum.

 

Mercedes covered the A/C lines in the 80's and 90's.

 

 

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8 hours ago, IBMobile said:

 Once the refrigerant is in a gaseous state the only way it can go back to a liquid is be compressed and sent through the condenser.  A properly filled A/C system will not cause slugging.  Over filled or filling the system with an inverted can will cause slugging. 

 

Insulating the piping after the orifice tube and before the evaporator is no problem.  After the evaporator some auto manufacturer choose to insulate the accumulator.  

 

  GM has done it with this products like this.

https://www.ebay.com/p/A-C-Accumulator-Insulator-ACDelco-GM-Original-Equipment-15-10614/79416292?iid=282964073381&_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D52475%26meid%3D84e53c92765446a885aca61308b093e9%26pid%3D100005%26rk%3D6%26rkt%3D12%26sd%3D161767073957%26itm%3D282964073381&_trksid=p2047675.c100005.m1851

 

Ford did it with a spray on insulation but it caused the accumulator made of steel to rust out, there was no way for the condensation to evaporate.  Now they are made of aluminum.

 

Mercedes covered the A/C lines in the 80's and 90's.

 

 

Since nearly no if any manufacturer currently uses insulation on MVAC plumbing there is probably little to no benefit in insulating any of the MVAC plumbing.

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Posted (edited)
8 hours ago, IBMobile said:

Mercedes covered the A/C lines in the 80's and 90's.

 

Back years ago when we were all talking in a fuel cooler thread..... I understand Mercedes also used a fuel line which tied into the AC system to cool the fuel...  Not sure if they still do or when they did, but a cool concept nonetheless.

 

Anyways, I'm glad you guys are confirming what I learned after trying to learn more about the AC system.  The only line I'll both insulating sometime in the future is that section of high pressure line exposed between the air filter and firewall.

Edited by KATOOM

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8 hours ago, IBMobile said:

Ford did it with a spray on insulation but it caused the accumulator made of steel to rust out, there was no way for the condensation to evaporate.  Now they are made of aluminum.

 

Funny... When I bring my truck into the shop and shutdown after my Ontario, OR trips the condensation/frost drips off so much water that it makes it way out the garage door. Quite a bit of water.

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10 hours ago, Mopar1973Man said:

 

Funny... When I bring my truck into the shop and shutdown after my Ontario, OR trips the condensation/frost drips off so much water that it makes it way out the garage door. Quite a bit of water.

You should see how much the AC systems drain water down here. 

 

L8tr

D

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12 hours ago, Mopar1973Man said:

 

Funny... When I bring my truck into the shop and shutdown after my Ontario, OR trips the condensation/frost drips off so much water that it makes it way out the garage door. Quite a bit of water.

 

1 hour ago, SilverMoose said:

You should see how much the AC systems drain water down here. 

 

 

Well in both cases we both should check the freon pressures I'm betting I'm a bit low and it creating more frost than sweat. It suppose to create cold air but not create a large amount of frost. If the compressor is cycling then your too low on freon as well. The compressor should stay locked all the time and create a sweaty cold but not a frosty cold. If it starts building frost then you could plug up the evaporator and performance of air flow will be reduced.  

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8 hours ago, Mopar1973Man said:

 

 

Well in both cases we both should check the freon pressures I'm betting I'm a bit low and it creating more frost than sweat. It suppose to create cold air but not create a large amount of frost. If the compressor is cycling then your too low on freon as well. The compressor should stay locked all the time and create a sweaty cold but not a frosty cold. If it starts building frost then you could plug up the evaporator and performance of air flow will be reduced.  

I get no frost just condensate draining....lots of it. I've dealt with frost before to the extent of blocking air flow.  Switched to vent to melt and the cycle continues

 

L8tr

D

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10 hours ago, SilverMoose said:

You should see how much the AC systems drain water down here. 

 

L8tr

D

You guys creating your own weather like nassholes with their supposed rocket engine tester

8 hours ago, Mopar1973Man said:

 

 

Well in both cases we both should check the freon pressures I'm betting I'm a bit low and it creating more frost than sweat. It suppose to create cold air but not create a large amount of frost. If the compressor is cycling then your too low on freon as well. The compressor should stay locked all the time and create a sweaty cold but not a frosty cold. If it starts building frost then you could plug up the evaporator and performance of air flow will be reduced.  

I thought they were supposed to cycle but very little, mostly staying on. But I do think too much:think:

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1 hour ago, Dieselfuture said:

I thought they were supposed to cycle but very little, mostly staying on.

 

Not really. That what wears out the clutch. Also if it does cycle out then the time the freon reverse direction pushing hot freon back into the evaporator making performance poor and warm. 

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On 6/19/2018 at 6:52 AM, Mopar1973Man said:

 

 No harm will happen. 

 

Like I wrapped my orifice tube to increase A/C performance since its the source of the cold for the cab. The accumulator is after the evaporator and any heat is sent to the condenser out front like @IBMobile said. 

 

Do you happen to have a picture of what portion of the line you wrapped? :thumb1:

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Sure... The entire orifice tube assembly. From the condenser out front to the evaporator at the firewall. This is the device that CREATES the cold. The accumulator is after the evaporator so it's got no performance benefit to cover it. Typically when I stop and the Quadzilla is running the engine for cold down I can open the hood and the accumulator is typically soaking wet and sweating hard core. Cold to the touch even after just climbing a 6% grade. I really doubt you going to gain anything with covering the line after the evaporator. Typically even on a 85*F day I've got to add a bit of heat to the temp setting because the cab is dipping down too COLD!

 

20180625_103843.jpg

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I will admit it is much much easier to install 1/2 inch pipe insulation on the orifice tube before installing to the truck. It a rather PITA to do it on the truck but not impossible though. 

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@Mopar1970man Why are you insulating the hot part of the pipe from the condenser to the orifice tube?

  I thought that you would leave that uncovered to let the heat escape like in the condenser.  You would only need to cover the pipe from the orifice tube, after the pressure drop, to the fire wall/evaporator to keep the cold in.

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9 minutes ago, IBMobile said:

@Mopar1970man Why are you insulating the hot part of the pipe from the condenser to the orifice tube?

  I thought that you would leave that uncovered to let the heat escape like in the condenser.  You would only need to cover the pipe from the orifice tube, after the pressure drop, to the fire wall/evaporator to keep the cold in.

 

Where's the orifice in this line?

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