Compressor Piping

[BJ42LX]

I'm putting together a compressor from component parts. I'd planned to use 3/8" copper refrigeration tubing with compression fittings to connect the output of the compressor to the check valve/tank.

A 10' coil costs about $22 at Home Depot. I only need about two feet.

I've got a bunch of 1/2" Type-L rigid copper and fittings laying around that I'm considering as an alternative.

My questions:

1) When a compressor is working hard the head can get get close to 300F. Is there a risk the sweat joints by the head will soften to the point of failure?

2) Is the rigid copper tubing with sweat joints more susceptible to fatigue failure than copper coil with compression fittings?

 

[Beemer533]

If I am not mistaken, typical solder used for plumbing has a melting point around 360 degrees... I would braze the connections instead.

 

[shoot summ]

I'm putting together a compressor from component parts. I'd planned to use 3/6" copper refrigeration tubing with compression fittings to connect the output of the compressor to the check valve/tank.

A 10' coil costs about $22 at Home Depot. I only need about two feet.

I've got a bunch of 1/2" Type-L rigid copper and fittings laying around that I'm considering as an alternative.

My questions:

1) When a compressor is working hard the head can get get close to 300F. Is there a risk the sweat joints close to the head will soften to the point of failure?

2) Is the rigid copper tubing with sweat joints more susceptible to fatigue failure than copper coil with compression fittings?

I'm anxious to hear the feedback on this. I just replaced my pump and went with pipe, and soldered connections. So far so good...

I will say that I'm not seeing anything near 300 degrees at the head on mine. Need to get a battery for my IR thermometer, but I can touch the outlet pipe, it's warm, but not 300 degrees.

 

[72Anthony]

What size compressor?

3/16 sounds way too small. Tubing is measured by outside diameter, so this is going to be a huge restriction.

 

[kbs2244]

I have used epoxy on both soft and hard copper tube with good results.

 

[Vegaman_Dan]

I spliced in an automatic drain for the tank that is activated by difference in pressure in the line from the tank to the cutoff switch. It was originally a relatively high temp plastic line, but I buggered it up and had to replace it. I was concerned about temperature, so just used copper line and compression fittings. 8" from the pump housing, it's very very hot. I put in four 5" coils of tubing to a T joint that ran to the cutoff switch and drain control.

The temp at the beginning of the first loop is too hot to touch. By the time it goes through the fourth loop it's at room temperature. For the cost of about four feet of tubing, it took care of the issue readily.

Copper pipe is excellent for this purpose.

 

[Nor'Easter]

I have 6 foot of 3/4 rubber hose before my air hits copper. Another 45 feet or so before it hits the air dryer, and then down to my drops.

 

[justanengineer]

Sorry, 3/8" nominal tube, which is 1/2 outside diameter, type L with wall thickness of 0.430".

What variety of compressor is it? My lil Quincy single stage ~11 cfm has 3/4 NPT ports in the head, which IIRC is ~1" od. I used a length of stainless braided high temp hose from a truck shop to connect into the tank, even with the compressor running continuous the hose doesnt get warm in the least.

 

[Fixnair]

3/8OD tubing will be fine. Use silver solder if you plan on sweating it together. Compression fittings will work fine also. Discharge on your typical reciprocating compressor will easily get up to 350*. If the compressor is worn out it can go above 400.

 

[pyro3256]

If cost is that much of an issue talk to a plumber could get a scrap piece that would work.

 

[Vegaman_Dan]

I have 6 foot of 3/4 rubber hose before my air hits copper. Another 45 feet or so before it hits the air dryer, and then down to my drops.

That rubber hose will do a great job of keeping the heat in the air until it hits copper. This is one of those rare cases where you don't want insulating materials.

I hope you have some drip lines or means to get rid of the water that is condensing before it hits the air dryer. In that amount of run of copper, you should have all the heat out of it fully by that distance.