Best way to flush tube/fin condenser at home?

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Charrie
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Best way to flush tube/fin condenser at home?

Post by Charrie »

The condenser is the only part I need to flush. No one has a condenser in stock or can get one any time soon. One of the issues I keep reading about is not getting all of the solvent out of the condenser. What can be used to make sure all of the flush solvent is out of the condenser? I have an air compressor but it is not dry air. I don't know how much it would cost to obtain a cylinder of nitrogen. Could it be done with helium?
I have 2 full propane and 1 full acetylene tank for a turbo torch but would guess that that is not very advisable.

There are only a couple of shops around here that do AC work and I don't know if I could pay them to flush just the condenser but I was going to make a few calls and see.

There are only 3 hoses in this system and one has a muffler on it. I found a new hose with the muffler and think the other two should be easy to flush. I am going to be removing the evaporator so I can check the firewall for rust and replace the gasket between the evaporator case and firewall. I may just replace the evaporator with a new one so that would leave only the condenser to worry about.

If I cant find anyone to flush it for me then I have access to one of the flush canisters you connect to the air compressor.

Any advise would be appreciated.

Thanks
Charie
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Re: Best way to flush tube/fin condenser at home?

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JohnHere
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Re: Best way to flush tube/fin condenser at home?

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Charrie wrote: Thu May 05, 2022 2:15 am The condenser is the only part I need to flush. No one has a condenser in stock or can get one any time soon. One of the issues I keep reading about is not getting all of the solvent out of the condenser. What can be used to make sure all of the flush solvent is out of the condenser? I have an air compressor but it is not dry air. I don't know how much it would cost to obtain a cylinder of nitrogen. Could it be done with helium?
I have 2 full propane and 1 full acetylene tank for a turbo torch but would guess that that is not very advisable.
You can use compressed air to blow-out the condenser, but it's not the ideal solution. Do you have any moisture separators on your airline upstream of the blowgun? If not, a good one to add (short of an expensive refrigerated air dryer or intercooler) is a desiccant dryer that contains replaceable desiccant beads. Several different ones are available in the market. They do a pretty good job of removing moisture from the air stream. You could then add a micron filter just downstream of the desiccant dryer to catch any small particulates. After using your now dry-as-possible shop air to blow-out the condenser, a good evacuation (several hours down to 500 microns, if possible) and a new receiver/dryer should ensure that the system is free from air and moisture before recharging it.

Nitrogen is great, but to purchase an appropriate setup (cylinder, regulator, gauge, hose, cart, etc.) for home use will probably be cost-prohibitive. I don't know about helium never having used it for that purpose. But I would stay away from the flammable gases for safety's sake.
Charrie wrote: Thu May 05, 2022 2:15 am There are only a couple of shops around here that do AC work and I don't know if I could pay them to flush just the condenser but I was going to make a few calls and see.
I would try that first. If you decide to do it yourself, check with Tim for the proper flushing solvent. He stocks "the good stuff."
Charrie wrote: Thu May 05, 2022 2:15 am There are only 3 hoses in this system and one has a muffler on it. I found a new hose with the muffler and think the other two should be easy to flush. I am going to be removing the evaporator so I can check the firewall for rust and replace the gasket between the evaporator case and firewall. I may just replace the evaporator with a new one so that would leave only the condenser to worry about.
With all of that done, plus a new or well-flushed (with oil only) original compressor, you should have a nice, clean and dry system to begin reassembling.
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Charrie
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Re: Best way to flush tube/fin condenser at home?

Post by Charrie »

Thanks for the replies.
Called 4 shops and no luck getting them to flush just the condenser. I did find one shop that said that they have a drier system on their compressor and that they would be willing to blow it out but probably not the 30 minutes that is recommended in what I have read.

My compressor is a small 10 gallon portable one and has no separator or dryer on it. HF does sell a desiccant dryer, oil/water separator and cheap in line hose filters that are supposed to filter out some moisture or oil. I wonder if a combination of all of those might be good enough for a one time job blowing the flushing solvent out of the condenser? And then perhaps lay the condenser in the sun for several hours?

Thanks
Charrie
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Re: Best way to flush tube/fin condenser at home?

Post by JohnHere »

Charrie wrote: Thu May 05, 2022 2:04 pm My compressor is a small 10 gallon portable one and has no separator or dryer on it. HF does sell a desiccant dryer, oil/water separator and cheap in line hose filters that are supposed to filter out some moisture or oil. I wonder if a combination of all of those might be good enough for a one time job blowing the flushing solvent out of the condenser? And then perhaps lay the condenser in the sun for several hours?
All of those filtration devices would certainly beat no filtration at all. Warming up the condenser by laying it out in the sun is a good idea. I would worry about insects getting into one of the open ports, though. Maybe you could use some type of air-permeable fine mesh to tape around each opening to prevent that.
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swampy 6x6
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Re: Best way to flush tube/fin condenser at home?

Post by swampy 6x6 »

hi
If your going to use compressed air , use whats called an air drying desiccant snake commonly used by spray painters to treat there air supply . Made by Devilbiss . Google it .

Use Shell X55 white spirit solvent . Very mild degreaser and cleaner . Will completely evaporate. The dispensing tool would be a air powered degreasing gun with reservoir and nozzle . Air supply thru air drying snake .
After solvent blow out use air only supplied via air snake to blow out the solvent + any debris /oil .
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Re: Best way to flush tube/fin condenser at home?

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swampy 6x6 wrote: Fri May 06, 2022 7:45 pm If your going to use compressed air , use whats called an air drying desiccant snake commonly used by spray painters to treat there air supply . Made by Devilbiss . Google it .
It depends on what will do the job. I frequently use my shop air system for many purposes that require dry air. So I prefer the wall-mounted desiccant dryers, which have "rechargeable" desiccant beads. These units work in conjunction with other filters on the airline.

In addition, each desiccant dryer unit has a window that permits viewing the desiccant color change, indicating when it needs replacing or recharging. In my experience, the snake doesn't have that and is essentially a single-use device. To my knowledge, there's no way to tell when the desiccant is saturated. You use it for, say, one automotive paint job, and then discard it. According to the manufacturer, the snake works as designed up to only 20 PSI--fine for HVLP spray guns, but not so much when you need 125 PSI for blowing-out MVAC components. Again, it depends on what will do the job for you. YMMV.
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