Flushing; automated or manual & HECAT

SeppW on Sun July 11, 2010 2:39 PM

Year: 1995
Make: Chevy
Model: Suburban
Engine Size: 5.7L
Refrigerant Type: R134a
Country of Origin: United States

I've posted on another forum about my project: "Stumped." Haven't had a catastrophic failure, yet. But, if I open up the system to make the suggested repairs, I figure I might as well flush it out while it's open. BTW, it has rear AC too. Anyway, I've been checking around with shops and dealers for flushing. To my surprise, I called the GM dealer I use and asked what a flush would cost. A red flag went up when the service writer didn't know what I was talking about. She asked me to hold on and was gone for several minutes. When she returned, she said spoke with the AC technician and he said no flushing was necessary. They would evacuate and recharge for $220.00. I said OK and thanked her for her time.

I thought that strange, because I read somewhere that every GM dealer had been supplied a machine, the ACR-2000 to be exact, that was capable of doing a refrigerant flush, as well as the other necessary functions. I've also read the ACR-2000 does not meet new EPA certifications, but can still be used. I would think a dealer would have the latest tool technology.

Called an independent shop. He has a flusher, but it is a closed-loop chemical-type that is being repaired. He did say though that they would do it "old school" by recovery, vacuum, and recharge. It is my understanding that recovery, evacuation, and vacuum does not remove oil and any debris from normal wear and tear.

At another shop, their machine was broken and shop owner was debating whether to buy a new one.

Likewise, in my search around the Northern Virginia area, I haven't been able to find an automotive ac specialty shop.

In regards to the HECAT DIY kit, I have a few questions;

1. Pros and cons to automated refrigerant flush machine and doing it manually with a HECAT DIY kit?

2. I've read the HECAT tech paper on flushing, so if I were using HECAT flush it would clean out the oil and muck despite it not having any chemical solvents or petroleum distillates (advertised as biodegradable, non-toxic)? I have found biodegradable, non-toxic cleaners are not as effective as chemical solvents (in other applications) to clean petroleum- and synthetic-based lubricants and other contaminants.

3. While researching about flushing evaporators, another publication suggest removing the evaporator to flush because if left in the vehicle the flush agent could pool at the bottom, or elsewhere, and even with purging flush could remain in liquid state and contaminate fresh oil. It went further to say that if no catastrophic failure has occurred, then not flushing evaporator was best course of action. The HECAT article is to the contrary. Why is there differing opinions? I for one am not going to tear out the dash to get at the evaporator albeit getting to the TXV in the rear will be a PITA.

4. If you happen to know a great AC shop in Northern Virginia, I'd appreciate the tip.

5. Or given that I haven't had a compressor failure, do I need to flush at all? It has been serviced once since 1995. I had in for a check up in 2K and shop did a recovery, recycle, vacuum, recharge, and replaced oil removed with clean oil.

Thanks in advance.

SeppW

Edited: Sun July 11, 2010 at 4:23 PM by SeppW

HECAT on Mon July 12, 2010 6:43 AM

Quote
Originally posted by: SeppW

1. Pros and cons to automated refrigerant flush machine and doing it manually with a HECAT DIY kit?

2. I've read the HECAT tech paper on flushing, so if I were using HECAT flush it would clean out the oil and muck despite it not having any chemical solvents or petroleum distillates (advertised as biodegradable, non-toxic)? I have found biodegradable, non-toxic cleaners are not as effective as chemical solvents (in other applications) to clean petroleum- and synthetic-based lubricants and other contaminants.

3. While researching about flushing evaporators, another publication suggest removing the evaporator to flush because if left in the vehicle the flush agent could pool at the bottom, or elsewhere, and even with purging flush could remain in liquid state and contaminate fresh oil. It went further to say that if no catastrophic failure has occurred, then not flushing evaporator was best course of action. The HECAT article is to the contrary. Why is there differing opinions? I for one am not going to tear out the dash to get at the evaporator albeit getting to the TXV in the rear will be a PITA.

4. If you happen to know a great AC shop in Northern Virginia, I'd appreciate the tip.

5. Or given that I haven't had a compressor failure, do I need to flush at all? It has been serviced once since 1995. I had in for a check up in 2K and shop did a recovery, recycle, vacuum, recharge, and replaced oil removed with clean oil.

1. HECAT manufactures both a dedicated refrigerant flushing method and the Pulsating series of solvent flushers. Refrigerant flushing equipment is much more expensive but eliminates the extra effort required and the concerns about proper and complete solvent removal. The RRR machine's poor flow capability and use of highly evaporative host refrigerant makes its ability to properly flush very limited.

2. You may have confused information on a water based degreaser with the HECAT Safe-Flush. Safe-Flush is a blend of petroleum and synthetic hydrocarbons (distillates).

3. If there is no need to tear into the dash to access the TXV (must be removed for flushing), then there is no need to remove the evap for flushing. Pooling is truly a concern when using non evaporative solvents. The difference of opinion comes from the fact that we focus on flushing, and understand what is required; very few if any others at all have such a focus. Many failed attempts at proper flushing combined with not understanding why the attempt failed; yield the claims that it cannot be done, don't do it, etc.

4. I would search for MACS member shop here

5. If you are comfortable that the oil is clean and is at the correct quantity, you do not need to flush. If there is any doubt, you will need to flush it out; take it to clean and DRY, and then you can add the proper amount of fresh oil.

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FLUSHING TECHNICAL PAPER vs2.pdfÃÂ

SeppW on Mon July 12, 2010 8:17 AM

So no risk a flush or solvent leaves an invisible residue after complete evaporation/purge that could get rehydrated with a liquid or lubricant and contaminate the oil/refrigerant?

This is the nontoxic, biodegradable product I was referring to: HECAT Safe Flush As stated earlier, when a cleaning agent says "nontoxic, biodegradable," while green sounding, it doesn't perform, if at all.

Edited: Mon July 12, 2010 at 9:21 AM by SeppW

HECAT on Mon July 12, 2010 10:06 AM

Quote
Originally posted by: SeppW
So no risk a flush or solvent leaves an invisible residue after complete evaporation/purge that could get rehydrated with a liquid or lubricant and contaminate the oil/refrigerant?

This is the nontoxic, biodegradable product I was referring to: HECAT Safe Flush As stated earlier, when a cleaning agent says "nontoxic, biodegradable," while green sounding, it doesn't perform, if at all.

All Solvents will leave residue. Trace residue is negligable and does no harm. Ounces of liquid cleaner is another story. This is why we must use a volatile solvent and (after liquid flushing) blow volumes of clean, DRY, filtered air, blow some more, and test to confirm the component is completely DRY before reassembly.

Safe-Flush is a non-hazardous solvent (blend) cleaner that is biodegradable in its pure form. It is a low odor, low VOC, CARB compliant alternative for CA regulated white solvents such as mineral spirits. The base is a low odor mildly agressive petroleum distillate and its cleaning performance (and ability to target PAG & POE oils) is excellerated with a citrus oil solvent. Our goal was to offer a product that worked and would not pose a major risk when aerosolized with many common flushing methods.; it works very well.

Yes there are more aggressive solvents available but these products come with more regulation compliance issues, storage issues, haz-mat shipping issues, packaging issues, flammability issues, technician health issues, that I do not wish to get involved with at this time. "Green" was never a primary driver, it just happened.

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FLUSHING TECHNICAL PAPER vs2.pdfÃÂ

SeppW on Mon July 12, 2010 10:25 AM

Got it. Thanks.

SeppW on Sun August 22, 2010 10:36 AM

Disregard, I' ll have to find another method of flush or skip it all together

One more follow-up question. My repair project, a '95 Chevy K1500 Suburban w/rear air, did not have a catastrophic failure, but I'll have to replace the entire front circuit (- the evap), along with compressor. The liquid and suction lines to rear and rear evap are ok, but I plan to flush the lines and both evaps. I can't get the liquid and suction lines disconnected at rear evap and not willing to risk the outcome of disconnecting. That said, it looks like I have to flush the rear circuit through the suction line forcing the flush from the flare connection in the engine compartment. I can remove the TXV and attach a drain hose off the liquid line outlet from evap. Removing the TXV allows the the liquid line to be flushed by itself.

If using the HECAT DIY kit, I'm assuming there would be enough pressure to clean the length of line and evap? If so, is there a risk the seals would fail after flushing with the safe flush product?

Edited: Mon August 23, 2010 at 9:12 PM by SeppW

HECAT on Tue August 24, 2010 5:35 AM

The Safe-Flush is compatible with the seals and hose (all elastomers) used in MVAC systems. I am sorry, but I read it twice and still did not completely follow your flushing plan. You cannot flush through a TXV with this Pulsating solvent method, or any other solvent method. Yes, the process uses considerable pressure and pulse energy; but the TXV restriction kills the pressure/energy used for effective cleaning, and also kills the velocity of the adequate "blow" to completely remove the solvent.

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FLUSHING TECHNICAL PAPER vs2.pdfÃÂ

SeppW on Tue August 24, 2010 7:18 PM

The TXV can be removed. I have the old one and drilled it out. But as I said and try as I might, the lines can't be disconnected from evaporator as I am not willing to risk having to replace the evaporator, which on the rear air Suburban means removing the rear HVAC case from the vehicle.

But it it's a moot point now. The pulsator kit is out of stock until maybe 3 weeks. I've got to get this thing back together. I'll have come up with another plan.

HECAT on Wed August 25, 2010 5:29 AM

OK, got your flush plan; yes you can flush through a long line and the evap with a clearanced flush fixture in place (drilled TXV). I do sincerely apologize. No one is more frustrated at the availability of the Pulsator Flush Gun than me; it's been a real hot summer. Good luck w/ your repair.

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