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Discussion Starter #81
Glad to hear that this mod is working. I would like to tackle the other parts of the AC line in the future.

Heavy duty pipe insulation: $35
Bandaids for scratched hands: $3
Getting a headache because your AC is DAMN cold: Priceless

:D
 

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Well, the AC is better, but the biggest problem is humidity. Once the humidity goes up above about 45%, the AC starts to suffer. The AC is much better since the replacement of the LP line, but it still isn't great. I guess I will just have to suffer with it. It isn't bad, it just isn't great.
 

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Discussion Starter #83
Did you do the insulation mod? I saw you got the leak fixed but I didn't see if you did the mod. Humidity will make the system work harder but if you do the mod at least it won't be fighting the heat of the engine compartment as well.
 

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Did you do the insulation mod? I saw you got the leak fixed but I didn't see if you did the mod. Humidity will make the system work harder but if you do the mod at least it won't be fighting the heat of the engine compartment as well.
Nope, had a hard time finding the insulation in this neck of the woods. Guess I should start looking again.
 

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Nice work.

A little information. The insulation will definitely help during high traffic and stop and go conditions. On the freeway however or under constant driving conditions you probably won't notice as much of a difference. The reasons why are, one you are getting a lot more air across the condenser as well as removing heat from the engine compartment from airflow. Also the compressor is now running at higher rpm allowing a larger volume to pass through the low pressure lines during a given time. Given the short length of the low pressure line any heat soak happening at higher flow is going to be less noticeable to the system especially with the condenser being able to run more efficiently with greater air flow.
One way to see how effective just the volume increase in flow is, is to take a thermometer and put it in the vent at idle. Now rev the engine and hold it at 3000 rpm for about 1 minute. You will see the temperature drop sometimes close to 5 degrees or more. I serviced AC systems in cars for years before graduating with my BSME.
 

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Discussion Starter #87
That was one of the things that I noticed. The AC would work great while moving on the freeway or around town but would suffer while sitting in traffic on a hot day. The added heat from the engine plus outside was overpowering the cooling capability of the system. The insulation seemed to help a lot.
 

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Discussion Starter #88
I live in rio rancho to. where did you pick up your insulation?
I think it was American Refrigeration Supplies Inc in Albuquerque. I'll double check with the Environmental Stress Screening (ESS) chamber tech at my work. He was the one that forwarded me to the right company when I inquired about AC performance in vehicles.

Stay tuned...
 

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Hot or Cold AC Line You Are Insulating?

Warhammer,

I touched the AC line you insulated after driving my Murano for about 10 miles. The line felt very hot to the hand. Being a layman of AC system, I wander if this section of AC line you insulated actually is hot and intended to be exposed to air for heat dissipation. Do you know for sure?
Thanks.
 

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False Alarm

Well, just realized that my touch of the AC line was 5 min. after engine stopped. Heat must have spread to the AC line by then. Will try to touch it again tomorrow after some drive. Most likely the line will be cold to touch.
Sorry for the false alarm.


Warhammer,

I touched the AC line you insulated after driving my Murano for about 10 miles. The line felt very hot to the hand. Being a layman of AC system, I wander if this section of AC line you insulated actually is hot and intended to be exposed to air for heat dissipation. Do you know for sure?
Thanks.
 

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Fire Hazard

Does anybody know if some of the materials discussed in this thread could be fire hazard being so close to the engine compartment?
 

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Discussion Starter #92
So far it hasn't posed an issue. While running, you'll notice the larger AC lines should be what is known in the AC industry as "beer can cold". The insulation will protect the AC lines from loosing its coldness in the hot engine compartment. Hence the reason why you feel it respond faster in slower traffic. On the highway, I'm sure you won't notice too much of a difference because of the amount of air flowing.
 

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Do you have the name or the part number of the heat wrap you bought? I saw so many different types, and just want to get exactly what you used. Thanks.
 

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Discussion Starter #94
The only thing I can say it's double adhesive high density pipe insulator. I'd have to call them and ask exactly what the part number is. I'd just go to your local professional hvac store and ask for something similar. They should have it.
 

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I truly hate beeing the prty pooper, the idea is great no doubt about that but I have to say that what you are doing to the lines is lethal in the long run. The material that was used looks rather spongy and absorbant. Also in general if moisture gets underneath this material it will rust and corrode the lines especially in areas like here in canada with the tonnes of salt they put on the roads
 

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Discussion Starter #96
Do you have the name or the part number of the heat wrap you bought? I saw so many different types, and just want to get exactly what you used. Thanks.
Man...call me a slacker. I completely forgot about this one. :28:

The place I got my material from is:

United Refrigeration
3337 Princeton Drive Northeast
Albuquerque, NM 87107-2013
(505) 883-9500

Just measure the OD of the line and get something similar to what I got. It's thick and will work. :)
 

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Looks like a good thing to do. The wife asked the right question: has it been corrected on the new models? if so one should be able to get the parts at the dealer for us with the early models.
And the insulation foam in your picture looks very much like what I have from my local hardware store to protect water pipes from freezing, is that what you have? But the tape you have used looks very slick, special type?

Very good and inexpensive idea to fix what should have been done by the factory!

I should have some of the sticky tape from a previous project which I will use (hoping to have enough left)

Thanks
 

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Thinking back to the original post in this thread about wrapping the low pressure lines, I am uncertain and doubtful how that can aid in the efficiency of the AC system. However, there might be an explanation for why it seems to cool down faster initially, but I also think it will impact the long term cooling ability, so allow me to think out loud here.

The low pressure lines are the refrigerant lines running out of the evaporator core through the engine compartment to the compressor. Insulating them won't make the evaporator lines colder when the compressor is in operation since by the time the refrigerant has reached the low pressure line in the engine compartment, it has already done its cooling job (way back in the evaporator core where the interior fan blows across). The job of the compressor is to take the cold low pressure refrigerant and compress it to a high pressure (and hotter gas). Wrapping the low pressure lines will no doubt keep the contents of those lines from absorbing heat from the engine compartment, but at the same time, you are asking the compressor to do more work - take something from a lower pressure to a higher pressure. If the refrigerant warmed somewhat (thereby increasing its pressure ever so slightly) traveling through the low pressure lines to the compressor (such as from engine bay heat) it would therefore present the compressor with less total work. So I posit that wrapping the lines makes the compressor actually work harder. Also, the Murano's compressor uses the incoming low pressure line to determine the appropriate output load (its a variable compressor) - on hotter days, the warm air passing over the evaporator coils will increase the temperature (and therefore pressure) in the low pressure lines, causing the swash plate within the compressor to swing open to increase total compressor output. If you wrap the low pressure lines, you lose that little bit of warming in the engine compartment, and the compressor may not kick on full capacity to deliver maximum performance.

So what benefit can wrapping the lines do? Well if you turn off the car, the line will heat soak, and since its a metal line connected to the metal coils within the evaporator core, wrapping the lines will indirectly keep the evaporator core cooler for a longer period. So if you park the car for ten minutes, its possible the AC might be ever so slightly instantly colder when you turn the car back on again. But this does nothing to increase the efficiency of the AC system since within seconds the evaporator will be ice cold again once the AC is turned on.

A tradeoff of keeping the evaporator cooler vs working the compressor (at low capacity) a little harder? Not worth it in my opinion.
 

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Nice job. I had my MO for 4 y's and half and was wondering if insulating the low pressure line would make any difference since I live in Saudi Arabia where temp exceeds 115 F in the summer. I insulated it 8 months ago and didn't notice any big difference.

In the end it worth the try. And I want to thank Warhammer and all other members who share their experience and knowledge with us, thank you all.
 
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