Author Topic: A/C charge pressures rv2 converted to sanden  (Read 1620 times)

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Offline daryl78powerwagon

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Re: A/C charge pressures rv2 converted to sanden
« Reply #50 on: September 25, 2020, 08:43:10 pm »
okay. if plumbed on the high side, but still a working switch, it would work to keep the system from coming on if the pressure were too low but still let it operate if undercharged (maybe like we're seeing). Your pressures would suggest a low charge with a R134 system; you have to look at the pressure charts for your gas.

I haven't looked over the charts for it, but I'd think charging until low side is somewhere around the 30's (without over pressurizing the high side) would be correct?

They are very similar to r12 for the pressures. However I put the guages on to check static pressure and its 120 on both sides which is right around where it should be at 100 degrees for R12 and 134.

So weird that I have the correct static pressure but no pressure when running. I think the txv is clogged or froze up. Parts guys said it wouldn't be the first time he's seen it.

Evacuating it now and going to pull a vac on it to 30 and leave it over night and see if it leaks.

I was able to tighten the high side Schrader valve a bit. A turn and a half with the tool, checked the low side wasn't as loose but tightened it also.

Still weird about the static pressure being spot on.

I think this chart is a static chart... No?

Its 100 in my garage right now relative humidity is 11%

So static pressure should be 109.

But am I suppose to be using the r 134 numbers on the guages or just the psi?
« Last Edit: September 25, 2020, 08:51:42 pm by daryl78powerwagon »
1978 w150 318/ 727/ np203/ d44/ 9.25 with a/c

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    Offline daryl78powerwagon

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    Re: A/C charge pressures rv2 converted to sanden
    « Reply #51 on: September 25, 2020, 08:54:38 pm »

    They are very similar to r12 for the pressures. However I put the guages on to check static pressure and its 120 on both sides which is right around where it should be at 100 degrees for R12 and 134.

    So weird that I have the correct static pressure but no pressure when running. I think the txv is clogged or froze up. Parts guys said it wouldn't be the first time he's seen it.

    Evacuating it now and going to pull a vac on it to 30 and leave it over night and see if it leaks.

    I was able to tighten the high side Schrader valve a bit. A turn and a half with the tool, checked the low side wasn't as loose but tightened it also.

    Still weird about the static pressure being spot on.

    I think this chart is a static chart... No?

    Its 100 in my garage right now relative humidity is 11%

    So static pressure should be 109.

    But am I suppose to be using the r 134 numbers on the guages or just the psi?

    So before I was at 120 I thought it was hotter out... So I guess I was overcharged before which make sense  cause we added some to test it.

    Still doesn't change how it was acting cause the extra charge came from yesterday's test.
    1978 w150 318/ 727/ np203/ d44/ 9.25 with a/c

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    Re: A/C charge pressures rv2 converted to sanden
    « Reply #52 on: September 25, 2020, 09:23:20 pm »
    Sorry, not sure about the gauges. I always just went with the straight psi. not sure if the different scales are meant for easy conversions or if it has any actual effect on the indicated pressure.
    '85 W150 SB, 408 stroker, Magnum manifolds, Performer RPM, 670 Truck Avenger, HEI ignition, Auburn LSD 9.25 and '82 D44 (non-CAD) with 3.55/3.54,  NV4500/NP241

    Offline daryl78powerwagon

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    Re: A/C charge pressures rv2 converted to sanden
    « Reply #53 on: September 25, 2020, 10:03:58 pm »
    Evaced it and tried to renkve the txv. Oil came spurting out, still had a bit of pressure. Left it open longer and have it on vac right now to pull it out.

    There's alot of oil right at the txv. Wonder if it was just clogged oil or if the evap is clogged with oil and there isn't enough velocity to get it back to the compressor?

    Maybe the condenser is clogged with oil.

    When we initially charged it when it was 130 in the garage we noticed the oil traveling through the sight glass.

    I read that if the system doesn't have enough velocity the oil can get stuck in the low spots if the system.

    So maybe it was just slugged up.

    Going to read a bit about that.
    What do you think.

    Might open another post to see if an ac guy can weigh in.
    1978 w150 318/ 727/ np203/ d44/ 9.25 with a/c

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    Re: A/C charge pressures rv2 converted to sanden
    « Reply #54 on: September 25, 2020, 10:52:31 pm »
    I guy with more experience would be helpful, but not sure if we have one around lately.  Personally, I would replace the txv and the pressure switch and start again. You shouldn't have oil sitting there like that. Was your oil amount accurate?

    When I put in the AC system for my truck, I started from scratch. So I had all new parts and it went smoothly. My other servicing has been leaks, relays, etc. Never had a blockage.
    '85 W150 SB, 408 stroker, Magnum manifolds, Performer RPM, 670 Truck Avenger, HEI ignition, Auburn LSD 9.25 and '82 D44 (non-CAD) with 3.55/3.54,  NV4500/NP241

    Offline daryl78powerwagon

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    Re: A/C charge pressures rv2 converted to sanden
    « Reply #55 on: September 25, 2020, 11:02:41 pm »
    Well when we first charged it something happened and I know for sure we pushed oil out of the compressor and into the system. Enough so that the sight glass totally turned bubbly and tan which was the oil come to find out. When things weren't adding up we shut it down for the night and restarted the next day. That's when it started acting like it should.

    But reading about oil logged evaporator comes down to many factors. Oil viscosity too thick which this sanden takes sp20 which is pag 100. Could be the suction line us to big, no pee traps??? Or could be simply how the lines are routed which could lead to not having the velocity to return oil back to the compressor efficiently. So this is a wtf type of what happened and how is it happening and what to do to remedy it.

    Are the pipes wrong size, is the oil too thick, could be a service fitting slowing down velocity? Was just from the initial flushing of the pump, why does it keep flushing the pump out?

    Could go on and on and I am sure it won't be an easy fix or remedy.

    The compressor had 5.5 oz in it and I checked with sanden and they said that's all that pump needs. Fsm for an 85 w150 says 7 to 8 oz but sanden, classic auto air and vintage air said the sanden comes with all the oil it needs to run. So I didn't add anymore. I do know that sanden sp20 oil is replaced by sp15 so maybe I should flush out the old thick oil and replace with the thinner sp15 but can't find pag compatible viscosity.

    Yes, definately need an ac guy to weigh in and likley am going to have to wait till Monday to talk to vknatge air and the shop that made the hoses and see what's up. Cause I don't think this is just a swap a part problem.
    1978 w150 318/ 727/ np203/ d44/ 9.25 with a/c

    Offline Richie19$

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    Re: A/C charge pressures rv2 converted to sanden
    « Reply #56 on: October 10, 2020, 11:23:07 pm »
    you need to use PAG 46 oil low viscocity. Also with the lines on the compressor they need to be higher than the evaporator kind of like a pea trap for the oil to keep it out of the evaporator. txv get clogged because the filter drier is bad or was never changed. debris can get in there from the install and really cause havoc. your best bet is to vac it down under 500 microns replace shrader valves with new replace filter drier and txv but flush it before all of this with nitrogen. you have to get all of the oil out of the compressor and start from scratch that is the only way to get your baseline for oil and refrigerant. otherwise how much is in there is unknown and could be sucking oil everywhere the problem you seem to have is too much oil in the system. the compressor really only needs an ounce or two of oil. not 7

    Offline daryl78powerwagon

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    Re: A/C charge pressures rv2 converted to sanden
    « Reply #57 on: October 11, 2020, 08:19:09 am »
    Everything on the system was brand new except the evap. Evap and new lines were flushed to make sure there was nothing in there. The only oil in the system was 4.5 oz that came in the sanden compressor. No more oil was added. The oil that came in the compressor was sp20 or pag 100.

    Lines at the compressor are higher then the evap however when we were charging it we did notice oil eventually flow through the site glass. Don't know that for sure but can only assume it as it turned cloudy then when it sat overnight it was clear again when the system was running.

    I know right now the system is overcharged and am going to evac it and recharge it with a scale this time instead of guessing the weight. Finding out that weight charging is better then guessing pressures. Real problem is being the system has been converted from a rv2 and has all new parts the only weight chart we can assume would be close would be that of an 85 w150. Original charge for that truck is 42oz of r12. So going to convert my coolant weight from that chart and charge it with that weight.

    Updated :

    I removed the freon and checked the oil. The oil Hass an amber color to it now. It was clear as could be before.

    Does this mean it was contaminated and do I need to flush it now and drain all the oil and start over?
    Here's pics of the oil.
    « Last Edit: October 11, 2020, 10:02:29 am by daryl78powerwagon »
    1978 w150 318/ 727/ np203/ d44/ 9.25 with a/c

    Offline daryl78powerwagon

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    Re: A/C charge pressures rv2 converted to sanden
    « Reply #58 on: October 17, 2020, 05:17:33 pm »
    Well finally broke down and found a mobile ac guy. He came out today and checked out the truck. He was pretty impressed how the r152a was doing. However the articles I sent him before he came over indicated it likley wouldn't work as good in a super high heat area like Phoenix. Which kinda makes sense but we went ahead and had him charge it with r134a so no more spaceship freon.

    Temps are about 2 degrees lower then what we were getting. All in all its acting exactly like it did with the r152a but just a smidge colder. You can also tell the compressor is working a little harder now due to the higher pressure. But ultimately it's blowing a bit colder and if i ever have any issues i can take it to any shop and have it checked out.

    But I do have to say we probably had it and seemed to have had it working and running right with the r152a.

    1978 w150 318/ 727/ np203/ d44/ 9.25 with a/c

     

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