Dual Evaporator Requirements

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gm76
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Dual Evaporator Requirements

Post by gm76 »

I have a 1986 33 foot motorhome with a 454 and the compressor is an R4. I would like to add a second evaporator midway in the coach for additional cooling. I would like it to work as one system whenever my front ac is turned on.
1: Will I need two orfice tubes or can I run both evaporators in series using just one ?
2: Would a larger condenser be necessary ?
3: Additionally, would a Sanden compressor be a better choice for overall performance regardless of any system mods ?
thank you
V8Power
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Re: Dual Evaporator Requirements

Post by V8Power »

The R4 compressor is great for your application. It is one of the biggest compressors ever built for cars. I would T the high pressure liquid line and run one orifice tube per evap.
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Cusser
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Re: Dual Evaporator Requirements

Post by Cusser »

gm76 wrote: Fri Jun 04, 2021 8:28 pm 1: ......can I run both evaporators in series ....?
Not in series; refrigerant vaporizes in an evaporator, and needs to be a liquid entering an evaporator. So an additional evaporator would need to be in parallel.
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Tim
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Re: Dual Evaporator Requirements

Post by Tim »

Rear systems will normally be an expansion valve design and have a drier, for the rear unit.
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gm76
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Re: Dual Evaporator Requirements

Post by gm76 »

Thanks (V8Power) for giving me confidence in the R4 and (Cusser) for reminding me of the difference between series and parallel. And (Tim) I don't know if it would be ok to have two different types of expansion valves in the same system, or is that how they are normally set up, that I don't know ??

I hope that the illustration I included seems like it would work in your opinions. thank you !!!
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tbirdtbird
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Re: Dual Evaporator Requirements

Post by tbirdtbird »

Like Tim said, the rear normally has the TXV when you have 2 evaps off one compr.
gm76
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Re: Dual Evaporator Requirements

Post by gm76 »

A little history: This is a 1993 Chevy engine and ac system that I merged into the 1986 motorhome. I removed the original drier and TXV from the stock system and plumbed in an accumulator and orfice tube. The system has been working ok. Now that I want to add a rear ac system, I'm a little confused about the combination of components needed to make everything work.
1: Is it ok to leave the front system with an orifice tube as is, and add the second evap with the TXV ??
OR
2: Can I build the system with (two) orifice tubes not using a TXV ??
thank you
tbirdtbird
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Re: Dual Evaporator Requirements

Post by tbirdtbird »

No offense but I am gonna let others jump in here and take over. The questions that keep coming are the same
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Tim
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Re: Dual Evaporator Requirements

Post by Tim »

Some just want you to tell them what they want to hear.

The last attempt to explain. Otherwise, it just gets repetitive.
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gm76
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Re: Dual Evaporator Requirements

Post by gm76 »

This last attempt to explain is just the diagram I needed to go forward with my project. I thank you for that. I understand that the rear is normally a TXV. I was just curious as to why two orifice tubes in the system wouldn't have the same results. thank you
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