Slow AC start (and a little discussion)

   #21  

Jack@European_Parts

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http://www.myturbodiesel.com/data/ph...e0514f94eb.jpg

a couple after and before charts.

just excel charts from data logged on three days.

with the new RCV installed, the temperature comes down much faster, the system gets into a control loop (reduced current) twice as fast as with the old valve.

the end state temperature is also much lower. a bit into my drive to work, with ac on max cold, and recirc, the evaporator temp read 0 degrees C

FREE FREE FREE


These valves can be cleaned/tanked and lubricated.
Everyone I have diagnosed as inactive or sporadic .........I have reinstalled with no issue after doing so, and additionally what I aforementioned.

I have cleaned about 75 of them personally........so that's a pretty good track record, not to mention the amount of TY emails I have received.

The valves can be had on EBay/Amazon from China for peanuts too, and the ones that are more expensive are no different in quality.

example search .........
http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&_nkw=PXE16&_sop=15
 
   #22  

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I think dyes are not brilliant to detect all leaks, the very very small ones anyway, the molecule size of the dye is greater than the molecule size of refrigerant and leaks can be missed, however, initially cost put aside, a mixture of hydrogen and nitrogen seems better at detecting those very very small leaks.
 
   #24  

mikeme

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Good point on the ability to clean, lubricate, and reuse the valve.

for myself, a single car diy person, it was more satisfying to have one issue at a time to deal with.

I purchased my replacement valve from a place in Florida.
EX_019.jpg


The old valve had some corrosion near the first O ring. (and I have never known corrosion on electric/mechanical parts to be a good thing long term)

anyone wants my old valve, I would be happy to send it to you in return for paypal of shipping, should you want to have a spare on hand, or just explore.


and in either case, replacement or cleaning of the RCV is much less expensive than a new compressor.
 
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   #26  

mikeme

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There was no evidence of discolored oil on the interior parts of the valve I removed.

I used a few Q tips to wipe the exterior part of the bore the valve sits in. this action did remove some dust/rust/lube from the section outside the exterior O ring seal. the inside parts looked quite clean using an inspection mirror and flashlight.

I put a few drops of PAG 46 from a new, small container, on the new valve to lubricate the O rings.

(I think I researched and this seems like close to the proper lube. not SANDEN, but I think the right weight of PAG)

I did not purge/clean the system, or replace the oil. (I did the valve replacement without loss of more than a few drops of lubricant, and with the compressor installed in the car, lock, stock, and belt.) the only thing I removed was the bottom engine compartment cover, the electric connector, and the valve (by removing the snap ring)

did pull a vacuum as noted, and refilled with straight R134a by weight.

will track performance, and perhaps come see you if I have further issues.

thanks for the links, replies and interest.
 
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   #27  

Jack@European_Parts

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I did not purge/clean the system, or replace the oil. (I did the valve replacement without loss of more than a few drops of lubricant, and with the compressor installed in the car, lock, stock, and belt.) the only thing I removed was the bottom engine compartment cover, the electric connector, and the valve (by removing the snap ring)

Very dumb cause a Q tip leaves residue and stuff can fall in. When cleaning a bore of such a type, it should be vacuumed out while picking or brushing.
Not changing the oil or checking the actual level is equally as dumb gross negligence, or is it extreme carelessness?

Are you trying to write helpful articles on how to damage additional parts of the AC system, further so people need to buy AC parts that are not moving this season?

FACT: AC parts are flat on wholesale end this season, and parts houses are stuck.....



did pull a vacuum as noted, and refilled with straight R134a by weight.

Did you know when you pull a vacuum on the system..... you are removing oil?

Additionally why this shows even more extreme carelessness or is it negligence? :p

Help below to inform others properly.......always read the manual and always check with design/specifications of the manufacture ....in this case Sanden.

10.2.2 Vacuum Pump Service

Vacuum pumps not receiving regular service will be unable to draw an adequate vacuum. In
most cases simple changing the pumps oil will correct the problem. Be sure to follow the
manufacturer’s recommendations for any maintenance on your evacuation pump. Change
the oil after use while the oil is still hot, because contaminants are still in suspension and will
be removed with the oil. If contaminants cool, solidify and stay in the pump, they lower
vacuum efficiency. In extreme cases, the oil stops lubricating and the pump seizes. The only
way to determine oil condition is to test vacuum pulled with an electronic vacuum gauge.
Contamination cannot be determined by oil color.





10.4 System Oil Balance
10.4.1 Oil Flow



Compressor lubrication occurs as the oil which circulates with the refrigerant passes

through the compressor crankcase during operation. The Sanden SD series
compressor achieves optimal durability and cooling performance when oil circulates
through the system at a ratio of 3.3% to 8% oil to refrigerant. Excess oil can act as an
insulator limiting heat transfer in the evaporator and condenser, while too little oil can
negatively effect durability.
10.4.2 In Laboratory Oil Amount Determination (OCR)



While the vehicle A/C is operating refrigerant samples are pulled from the liquid

refrigerant line at several operating conditions. These samples are weighed then the
refrigerant is evaporated from the sample leaving oil which is weighed again. Dividing
the mass of the oil by the mass of the refrigerant plus oil will yield a ratio at the
conditions the sample was taken. This measurement is referred to as the Oil
Circulation Ratio or OCR.
10.4.2 Oil Checking Is Not Required Under Normal Conditions



The mobile refrigeration system is a closed loop system, hence it is not necessary to

check or change oil in systems functioning normally and not in need of repair. The
system isolates the oil and refrigerant from moisture and contaminants, while normal
operating temperatures will be well below a point that will cause oil degradation.
10.4.4 When Oil Addition or Balancing is required



Compressor or component replacement




Loss of refrigerant and oil mixture




Adding oil to the system is required when refrigerant loss occurs due to leakage at any

system component. Since oil is held in suspension with the refrigerant, oil will be lost
with the escaping refrigerant gas. Oil will need to be inspected for contamination
during repairs to determine if flushing is required
10.4.5 Oil Addition When Replacing System Components



A/C systems are designed to have a given oil charge so during component

replacement the goal should be to maintain the initial factory oil charge. It is
understood that system oil balance resulting from service activities is not an exact
process, however using these guidelines should roughly maintain the OEM system oil
charge.


Operating conditions at the time of system shut down will determine where and how

much oil settles in any given component in the A/C system. Therefore the exact
amount of oil removed during refrigerant loss or component replacement can only be
estimated in a shop environment. Sanden recommends adding SP-15 oil using these
guidelines.



System Oil Amount


Oil circulates with the refrigerant during operation. During off periods oil will settle in all

system components with more collecting in cool components like evaporators,
accumulator and suction lines.
During shut down oil settles through out the system collecting in all components

Compressor
Evaporator
Drier
Expansion Condenser

Oil Replacement Amount During Service



When replacing a system component the goal is to


restore to the original factory oil amount. This amount can
be found on the compressor label. Use the chart below as
a guide for restoring oil quantities when replacing system
components.

Typical Oil Amount
Large Truck
Typical Oil Amount
Component Passenger Car


fl. oz. cc fl. oz. cc
Major System Leak
Suction Line To Rear Evaporator
Accumulator
3 88 1.5 44
Condenser
Evaporator
2 60 1 30
Receiver Drier
Minor System Leak
Suction Line To Front Evaporator
Other Hoses or Hard Lines
1 30 .5 15
Compressor Equal to amount drained from old compressor

Example


Large truck with no leak requires new compressor, suction hose
and drier.
Drain oil from old compressor = 3 oz
Oil remaining in old compressor = .5 oz (
see note below)


Oil lost from old suction hose = 1oz (from table)
Oil remaining in old drier = 1oz (from table)

Amount to be added 5.5 oz


Note: When draining the old compressor roughly .5oz will remain in the compressor as
film coating all internal surfaces




.


thanks for the links, replies and interest.

No problem.
Hope above helps........ extreme carelessness verse negligence, is just a hot topic this past 2 weeks in the media, and is why it is ref.....just me being a wise ass.

It should be noted that the manuals I aforementioned in PDF or the OEM are a specific "fact pattern".........:thumbs:
 
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   #28  

mikeme

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Congratulations on your self-assurance that you are better at all this than anyone else will ever be.
 
   #29  

Jack@European_Parts

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Congratulations on your self-assurance that you are better at all this than anyone else will ever be.

Hey man....... was just pointing out stuff that you missed, which was seriously important to help "you" or the collective.

Yeah I can be that asshole too....:p

Don't you want debate or just chocolate sprinkles/sugar cones, Unicorns etc.?
This stuff is textbook.........this is not.

It's most important to know how/why something works, or fails, and correct the problem, not just the result.

Do you want to take a pill box or get cured?

See the two o-rings in your pic?
In between is the fine screen, which plugs up?

This same type screen is what causes cam adjusters to fail too, or other type noid hydrostatic devices.

You could if lazy, and didn't want to check oil or for contaminates....... just break holes in it and be back online.



EX_019.jpg
 
   #30  

mikeme

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All that is true, and you do have a good point.

I did look at the old valve, and noted very clean lubricant.

My use of the q tips was on the part of the bore in the compressor case that is outside the seals. tradeoff to catch some rust/dirt/etc so the new valve would have less chance to contaminate the o rings on the way in.

checked with the shop that did my recovery, and they usually put a half ounce of lube in to make up for what comes out.

I think some recovery equipment will separate out lube from recovered refrigerant so you can inspect and measure it, and maintain the proper levels. seems the shop I engaged does not have such ability to quantify.

my system is rated at 110 cc plus or minus ten. Half an ounce is 15 cc (more or less)

so my system is likely a bit shy on the lubricant amount.

my condenser has enough damage I am planning to replace it (after the weather improves. to hot for driveway repairs if you ask me).

I will adjust the replacement refrigerant lubricant amount when I do that replacement. usual process would be 10% of 110cc, add allowance for two recovery actions, and an ounce and a half seems about right.

(a full system flush would be required to start from scratch and really know how much is in the system)


My old valve does not seem to have any contamination on the screen you mentioned, but does have corrosion on the outside case (between the system-sealing O ring and the electric connector)

I have not done any failure analysis on the old valve.

Thanks again for your attention on this.

just like a prickly pear fruit, there is some good stuff there, once you get past the rough appearance.
 
   #31  

Jack@European_Parts

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:thumbs:

I think you could hook up a set of gages in driveway and see if the PSI is too high, and in some cases I see that systems are overfilled.

Here is something that happened to me....

I had a new AC and Heating system put in my house in 2010 by a professional.
I had to use them, because It was a requirement to receive a rebate from the state, for using approved contractors through the electric utility.

So here is what happened.

They installed and I got my rebate, that made the cost for me less than if I did it myself.

The first issue.......AC no worky....call contractor.

Contractor came fast and changed the fuse with a higher than rated fuse and I documented.
AC worked again.
Two days later Fuse being too big blew board...he replaces board.
Turns out the relay outside was faulty.

China stink bugs went into the condenser outside, and nested in the high voltage relay for the compressor, due to no gasket, further blowing the fuse on the board.
When the relay pulled in, the bugs would get squashed, and the guts being conductive would complete circuits from the T stat wire, to the 220 V .......ahh oh.

Contractor says well this isn't our fault and under warranty.

Keep in mind I was documenting all.
I was like okay........ so the bugs got in there, because you negated installing a gasket; and now I'm responsible for the FOD because you didn't do your job right.
I than opened the book from the AC install, and noted showing the gasket requirement, I then had a capitulated contractor.

2 years later it gets real hot like 102 record temps and the AC is not hitting targets inside with a short cycle.

Now it's out of warranty and I'm like okay, I have to get these new gages and the commercial Freon thinking maybe low.

So ordered the stuff and waited a couple days.......meanwhile waiting checked for leaks with detector found nothing.

Hook up gages and low and behold all is fine NFF @ about 80 , next day it's 100+ again and here is the short cycle.

Hook up gages and the high side was off the charts.........know why?

TO MUCH FREON ..............! :banghead:

Remove and recover the overage and the AC is way colder........

I have found this situation on more than a handful of friends AC in their house, and almost believe that some contractors deliberately overfill to cause a service call later or system failure.
I have found the same in automotive over the years.

My policy in my shop was for the last 25 years to charge AC as a gratuity being a hero on a hot day.

So now I basically almost trust no one in their abilities anymore, until I have personally verified it or know them a really long time to establish a work ethic.
 
   #32  

mikeme

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If I have learned anything, it is that a set of gauges will tell a few things, but with the variable displacement systems, the gauge will not tell you much.

There is really no direct way to get actual current displacement of the pump, and no way to see amount of refrigerant in the system, (except to remove, weigh using proper equipment, and re-fill)

lubricant amount in the system is a similar problem. no good way to know for sure unless you clean it out and start over, (but keeping track of deltas helps)

kind of like using a map and compass. you have to know where you are to figure out which way to move to get where you want to go.
 
   #33  

Jack@European_Parts

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If I have learned anything, it is that a set of gauges will tell a few things, but with the variable displacement systems, the gauge will not tell you much.

There is really no direct way to get actual current displacement of the pump, and no way to see amount of refrigerant in the system, (except to remove, weigh using proper equipment, and re-fill)

lubricant amount in the system is a similar problem. no good way to know for sure unless you clean it out and start over, (but keeping track of deltas helps)

kind of like using a map and compass. you have to know where you are to figure out which way to move to get where you want to go.

I disagree......... the gages will tell you allot more than you might think.....the temp based on humidity/RPM, and fan operation.

Oil can be extracted with a vacuum sucking device very easily........ even with compressor installed.

Examples: https://www.google.com/search?q=vac...XDRAQ_AUIBygC#tbm=isch&q=vacula+brake+bleeder

https://www.google.com/search?q=vac...hVFqR4KHftXDRAQ_AUIBygC#tbm=isch&q=mighty+vac



Think of the gages and your eyes as a GPS.........:thumbs:

Sometimes less is more..........
 
   #35  

Jack@European_Parts

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http://www.tooltopia.com/robinair-16256.aspx

and tools exist to add oil to a fully charged system.



Jack, (and any other experienced professional)

in your experience, what is the range of amounts of oil pulled out with a refrigerant recovery?

That tool is a POS........and a rip!

It's a variable.
RTFB aforementioned PDF's......
Depends on where the lines are put, strength of pump, and where the vacuum pump is in relation to height of system.

A better oil injector type via the lines is one that can be filled and inline with the refrigerant always under PSI with ball valve control.

Example and not endorsed seller:

http://www.ebay.com/itm/1-4SAE-134a...ash=item3a936c8ebc:g:tY0AAOSw91NTum0d&vxp=mtr
 
   #36  

mikeme

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the tool worked pretty slick.

I put 10cc or so in.

It would have been more cost-effective to have planned ahead, but it is what it is.
 
   #37  

Jack@European_Parts

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the tool worked pretty slick.

I put 10cc or so in.

It would have been more cost-effective to have planned ahead, but it is what it is.

Jacks wartime method and inverse poor mans solution........

There is nothing slick about a syringe on a hose.......& for over 70 USD......:banghead:

You could do the same with a turkey baster from the dollar store, and by further removing a Schrader in the low side gage hose.

https://www.google.com/search?q=che...KEwip5dvDxozOAhWMaT4KHc1KBLwQ_AUIBygC&dpr=0.9

And the Turkey basters can be had with measurement indicators for the complete moron too...........:thumbs:
 
   #38  

mikeme

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You must have missed the primary feature of this tool, it works with the system fully pressurized.

try that with a turkey baster.

(I agree $70 and some is a little high, but cost to me is less than running through another recovery/recharge cycle.)

thanks for your frugal encouragement. :cool:
 
   #39  

Jack@European_Parts

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You must have missed the primary feature of this tool, it works with the system fully pressurized.

try that with a turkey baster.

(I agree $70 and some is a little high, but cost to me is less than running through another recovery/recharge cycle.)

thanks for your frugal encouragement.
cool.gif


Ummmm.....my way a charged system can be injected the same as your aforementioned tool, regardless of which is chosen, there is no advantage to either method other than cost.

I hope people chose to save money.
Not to mention oil charge cans are less of a hassle for the guy at home verse a commercial 30 pound tank.

It's not about cookies and milk time encouragement, it's about debate.

You stated "a little discussion....."

Maybe not make threads which sound like an infomercial.....because yours certainly do......IMHO.


 
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   #40  

mikeme

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Jack, it is a discussion and sharing of what I find out and know. links are just examples for clarity. I have no interest in or any $$ return from any one following a link.

I really would like to see more info on how you think you can use a turkey baster to inject oil into a pressurized system. the tool I used includes several features you would have to provide for. proper adapter to seal to the low pressure servicing port. operable control to open the Schrader valve on the port. seems like an internal check valve isolates the system pressure from the oil container. the operable oring sealed piston on the tool allows manipulation to displace air from the tool, and then to provide enough force to move oil past the internal check valve, and into the system.

I agree that the cost of such a tool could be avoided by thinking ahead. Not sure the oil included in generic cans is a good match for the weight of oil specified for the sanden compressor in my car. one would want to pay attention.
http://www.walmart.com/ip/Fjc-Inc.-...62769&wl11=online&wl12=41262772&wl13=&veh=sem
seems like it would be suitable, PAG 46, but has 2 oz of oil. seems like it would be difficult to put a lower amount of oil into the system.

(side observation) Jack, some of the advice you provide not only comes with a dose of abuse and belittling, but it seems to come too late to do any proactive thing with it. You followed and commented on my posts until after it was clear that I had had the R134a recovered, and had refilled it before bringing into the conversation the helpful fact that recovery pulls oil with it.
It would have been more helpful to have pointed that out earlier instead of diverting the conversation to express your distain for a DIY person, talking about schmucks and the like.

now back to a relevant detail which may (or may not...) be of interest to others,

a point sample of data from my HVAC controller. (using VCDS advanced measuring blocks)

Address 08: Auto HVAC (1K0 820 047 HS)

15:47:06
0.0 Compressor Shut-Off Code
1500 /min Engine Speed
0.820 A Compressor Current (specified)
1900 /min Compressor Speed
7.5 Nm Compressor Load
18.0 bar Coolant Pressure
39.5°C Outside Temp. (unfiltered)
93.0°C Coolant Temperature
12.0°C Outlet Blower Temperature
10.0°C Evaporator Temperature
ON Fan/Blower Status​

this was yesterday, when we had record high temperatures (100f), with uncomfortable humidity. Fan was set to 3, AC on, but not recirculate, and temperature request around 9 or ten oclock on the dial. the system was working as hard as it could. When stopped at a light, the evaporator temperature would increase a couple degrees.

it may be that improved performance would be possible with a replaced, or improved condenser. (improved by further cleaning, opening air passages....)
 
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