11,000 BTU DX GEO Heating

[Fordguy64]

Can't wait to see the results

[AC_Hacker]

Originally Posted by MEMPHIS91

So today went MUCH better. The problem I ran into was that I cooked my reversing valve. I had been very careful but using map gas, but it just has WAY to wide a flame, and it takes much longer to heat up therefore heating the entire valve enough to cook the nylon o rings on the piston shuttle.

MEMPHIS91,

Has anyone spoken to you about the technique of using wet rags to limit heat flow around your braze areas??

It works really great. The rags need to be very wet, and secured close with a little wire, to the area or tubing near to your brazing area.

Another handy thing is some kind of heat deflector or heat-proof blanket to shield delicate parts from the heat of the Brazing flame. I may have neglected to mention that in the Manifesto, but I have a well-equipped pottery supply store near my house, and I got about a square foot of refractory blanket for maybe $10 or so. It needs careful handling, but it works really well. You can blast a torch at it for a long time, with relatively little heat coming through the other side.

The combination of wet rags tied to your tubing and other heat sensitive parts, and the refractory blanket, should do the job of controlling unwanted heat.

-AC

[MEMPHIS91]

That's a good idea AC! Thank you. I used a small piece of metal to shield some things but it conducts heat really fast. I did use rags, but the amount of heat it takes to braze 3/4 is more than the map could handle. I'll start the install this morning.

[pinballlooking]

Good luck with the installation. Love all the updates.

[jeff5may]

Just another pothole in the road, man. I burned up a few access valves in the beginning, too. Now I dismantle as much of the rubber or plastic as possible before torches are raised. With reversing valves, check valves, txvs, etc., I wrap them up like a sprained ankle. Wet band-aid gauze or rolled up cheesecloth works very well for this purpose.

Before the torches are lit, everything should be fit up and support its own weight so that nothing drops or flies apart when components expand and contract against each other. All tools and equipment should be within arms reach, as well as a fire extinguisher.

On everything above about a quarter inch (7mm), I use a second torch to heat the joint on the side away from the heat-sensitive component. As soon as a little heat soaks into the joint, I raise the brazing torch and start swiping filler rod. With a little practice, you can be done brazing the joint before your rags start to steam. If you aren't done brazing the joint by the time the rags start steaming, the clock is ticking. Once the water in intimate contact with your component boils off, its guts start melting. Either stop and apply more water or make haste and finish.

Now that you have a proper torch, this whole process will be much easier for you. Just make sure not to burn any holes in your work. Even though they look small like a toy, those bad boys can cut metal like a scalpel.

What color are you going to paint the wood enclosure? I think it would look good in a blue, something close to the fan in hue. Ford tractor blue comes to mind... Just a thought.

[MEMPHIS91]

Thanks for all the tips on brazing guys! Came in handy this morning.
I only have a few issues and things will be running great. It works as is though.
Sorry the color is way off, the LED greenhouse lights are still on, I got the stainless steel coil in and sunk to the bottom.

This is the stainless to copper braze. The 45% silver with blue flux stuff is awesome! But gosh it stinks some kind of bad!

This is all of the back before I started brazing. From closest to farthest, (left to right) the discharge line to the fish tank, then the suction line with a sight glass and filter/drier, then the discharge line leading to the SUD115 and cap tubes (not included in the picture).

This is the SUD115 with 4 equal length cap tubes.

This is everything put together just doing some pressure leak test, only found one leak, then a vacuumed the crap out of it.

This is my pressures and temps. I could have read the built in gauges but of course I put the low on the high and the high on the low side.


I was getting good heat out of it but the sad news I the reversing valve idea isn't working. I tried it when everything was running and on start up after resting for 5 minutes. I think my suction pressure may be too high. I KNOW I didn't get it too hot. I took extreme measures to make sure of it. I'm still trying to think on it, but may need to go with some kind of solenoid valve.
Any way that is the only problems, I will do more testing and fine tuning with it gets cold tonight.

And yes Jeff you are right a good blue will look good on it. It will match the 55 gallon barrel too.

[pinballlooking]

Do you have a picture of the SS coil in the fish tank?

[MEMPHIS91]

Sure do man, the water is hard to see through though. I just looped it several times and then brazed with the SS out of the water. So no copper is touching the water.

Here is a better picture of the SUD115 and cap tubes. I now have sightly clamped 3 down and my suction pressure is a 27 psi and discharge at 185 psi.

Here is the guts of the reversing valve I got to hot, I took it apart to understand it better so maybe I can figure out why this set up isn't working.
This is it just taken apart.


This is how it slides to switch to one side.

And the other side.

My plan is to swap somethings around. I'm going to open the suction part back up and swap the discharge of the compressor into it. Plus swap my gauges to the way they should be.
More data soon.

[jeff5may]

I have had problems with reversing valves not doing what they should. In all cases, it had something to do with the pilot valve or the solenoid coil. On an older valve, the spool in the pilot valve was stuck in the inactive position. I freed it by using a high-energy magnet from a hard drive. The others were either a bad coil or a wrongly positioned coil on the pilot valve.

Also remember that the reversing spool needs differential pressure to operate. In your case, the pilot valve line connected to the suction line of the main valve still needs suction on it.

[MEMPHIS91]

Jeff that's good to know. In this case the valve is new, and yes I do have the auction tied into the pilot valve. The pilot valve is clicking loudly every time the solenoid is engaged. I just know this idea should work, it works great on paper Lol