Orifice tube install... - Page 2 - PeachParts Mercedes-Benz Forum

engatwork · #16 07-14-2011, 08:11 AM

Quote:

Greg is silent... His mind must be blown...

I'm sure he is waiting to see how this turns out

.

Now you got to figure out how much oil to put into it. I would try to find the oil fill capacity specs for each individual part. Example is the accumulator, whatever Chebby specs for oil capacity put that much in. Dryer, same thing for whatever it is spec'd for, etc.... You should be able to find this information on the net.

leathermang · #17 07-14-2011, 10:42 AM

Jim, he posts at midnight.... and wonders why I do not immediately respond... I have to sleep some time...

I am worried about the distance from the evaporator that the accumulator is... if you are going to put the temperature cycling switch on the accumulator instead of the exit to the evaporator...
It may not make any difference.... at the very least I think you will need to factor that into your refrigerant filling.... making it very slow to stabilize the situation and see that you do not respond to a low point in the cycle as a ' fill indicator ' and wind up with an overcharge.
You told me the orifice tube had a filter on both sides of it... is that still true ? My book says that is SOP on a CCOT system.

The accumulator has no way to exert suction on its own... perhaps yours was packaged with a vacuum in it... and you noticed that...

Capacity on the high pressure side is great... as it has the chance of storing ready to use refrigerant from running at speed to using it while stuck in traffic.... banking the compressor ' work product ' in a way....

1980sd · #18 07-14-2011, 11:39 AM

Glad you're OK Greg. I was worried about exposing you to such high levels of AWESOME. I guess it just makes you tired and cranky. I'm trying to keep the AWESOME in check. For your sake...

The distance between the evaporator and accumulator also bugs me. I haven't found an example of a system with the accumulator that far away. Some do have rather long tubes between the evaporator and accumulator but they seem to have metal tubes between them.

There are screens on both sides of the orifice tube. They are made that way.

If it works I may have to "tune" the system with different cycling parameters and maybe different orifice tube sizes. There is also the charge volume...

Jim, I'm going to re read the Sanden oil recommendations. Maybe 1.5 oz of oil in both the drier and accumulator? Sanden compressors don't seem to have oiling problems like R4's so I don't think being conservative will hurt anything.

Waiting on fittings...

compu_85 · #19 07-14-2011, 11:42 AM

Perhaps I'm missing something here, but do you have the accumulator before the orifice tube? On my friend OT equipped F350 the accumulator lives after the evaporator. And it does get rather cold.

-J

leathermang · #20 07-14-2011, 11:52 AM

Quote:

Originally Posted by 1980sd

.... I haven't found an example of a system with the accumulator that far away. Some do have rather long tubes between the evaporator and accumulator but they seem to have metal tubes between them....

I have not seen them far away either.. might be accident... but I worry that it is needed.... a metal tube insulated on the outside could be pretty long and not adversely affect the temperature readings of out of the evaporator..... but messing with that relationship without knowing if it is important could cost you a lot of redo time... and a certain amount of Awesome Cred...

leathermang · #21 07-14-2011, 11:59 AM

Quote:

Originally Posted by compu_85

Perhaps I'm missing something here, but do you have the accumulator before the orifice tube? On my friend OT equipped F350 the accumulator lives after the evaporator. And it does get rather cold. -J

No, not before the orifice tube... it is before the compressor to make sure ( cross your fingers ) that the compressor does not get any actual LIQUID... which could ruin it in short order..
It gets cold because of a ' fudge factor ' in the workings of the evaporator refrigerant controls.... if you adjusted them to where it was getting refrigerant vapor completely reduced to the temperature of the ambient air temp inside the cabin... then you would be taking a chance on not putting enough sprayed refrigerant into the evaporator to keep up with the cooling needs of the passengers...
So a little leakage of still cold refrigerant making its way to the accumulator is fine and to be preferred if the mission is to make sure the passenger's needs are met as best as the rest of the system can manage to do that...
You do not want to create an unnecessary and artificial bottleneck there at the expense of the passengers air temperature...

1980sd · #22 07-14-2011, 12:00 PM

Quote:

Originally Posted by compu_85

Perhaps I'm missing something here, but do you have the accumulator before the orifice tube? On my friend OT equipped F350 the accumulator lives after the evaporator. And it does get rather cold.

-J

I'll have the orifice tube on the #6 line between the receiver/drier and the evaporator and the accumulator on the #10 line between the evaporator and compressor.

This is pretty much the arrangement on most mobile 134a systems that I've seen that work well.

compu_85 · #23 07-14-2011, 01:35 PM

Got it, thanks.

1980sd · #24 07-14-2011, 05:25 PM

I need to re-do the whole suction side from the evaporator back to the compressor.

I was going to use #10 hose exiting the evaporator to the accumulator and #10 hose from the accumulator to the compressor.(suction side) Seems I'm going to have to use #12 hose from the evaporator to the accumulator because of the fittings available. It was originally #12 so I actually feel better about having to do it this way.

Rounding up the fittings is a real chore because no one around here stocks this stuff

They gave me an old 4 Seasons catalog which has a lot of information. Compressors, blower motors, switches, etc...

It should help me with getting the CCOT stuff worked out.

leathermang · #25 07-14-2011, 05:55 PM

Well, the bigger the low pressure side is the less work/friction restriction, and better flow for everything....and less load....

1980sd · #26 07-14-2011, 06:11 PM

Quote:

Originally Posted by leathermang

Well, the bigger the low pressure side is the less work/friction restriction, and better flow for everything....and less load....

It originally had what I think is #6 reduced diameter barrier hose from the receiver to the TXV. I now have regular #6 hose.

I had #12 on the suction side and #8 from the compressor to the the condenser. And this will now stay the same.

I have a lot of rubber hose and fittings where OEM type stuff seems to keep with more metal in the system. I was looking at a friends Toyota truck today and the system is ALL aluminum except for short rubber lines at the compressor. No accumulator or receiver that I could find either

CCOT switch parameters:

1: on at 38 off at 25
2: on at 44 off at 21
3: on at 47 off at 28

All are in psi and either of the three will screw onto the accumulator. Just pick one?

leathermang · #27 07-14-2011, 06:34 PM

Get your shotgun out and have someone throw them into the air...all at the same time... the one that does not get hit by buckshot is the one to use....

1980sd · #28 07-14-2011, 07:17 PM

What would be a good guess at what the best pressure should be while running?

Go with the one with the greatest spread? I'm thinking I may need to avoid high pressures?

I should have gobs of refrigerant in the system with both a receiver and an accumulator.

I kind of think of the receiver as sort of an extension of the condenser and the accumulator as sort of an extension of the evaporator and my compressor will be real close to the accumulator.

Supposedly the old copper tube/fin evaporators don't flow as well as the new ones so I'm guessing that It'll show up in the accumulator pressures. Will this make it higher or lower? And what will the high side pressures be doing?

leathermang · #29 07-14-2011, 07:29 PM

Quote:

Originally Posted by 1980sd

....I kind of think of the receiver as sort of an extension of the condenser and the accumulator as sort of an extension of the evaporator and my compressor will be real close to the accumulator....

That is a reasonable concept...
I would go with the one with the greatest spread...
Gobs might be a little optimistic... as you can not load up the accumulator..

engatwork · #30 07-14-2011, 07:34 PM

Quote:

I'm thinking I may need to avoid high pressures?

I'd try to operate it at as low a pressure that you can and it still work good.