Plumbing part 5 - HX inlet and solenoid

Pluuuumbing! 

First order of today's business is the line from the inlet to the HX - this one is always open but requires an additional connection to the expansion valve at the sump. 

I found that the tubing bender has a tendency to drag the section around the mandrel which screws both the tube and the placement of the bend. In order to get them in exactly the right place, I am using a clamp collar as a stopper. The marks on the tubing are either the start, middle or end of the bend and are aligned with the degree marks on the bender where they will end up when the bend is made; by measuring or simply rolling the straight tube around the mandrel (if that is even sort of clear). 

Here it is in the bender.

This creates a bend with a radius of about 2.75", but I need this one to be smaller so I tightened it up with the Alien-critter-tool afterwards. Two more bends added and one to go.

This is a skill that needs a fair amount of practice in order to deliver good (and precise) results. I haven't done this for a while, so the first one took quite a bit of time (and plenty of adjustment). I have lots of admiration for the electrical conduit trade (ever looked at a manual for one of those deceptively simple looking tubing benders they use?). There is no correcting bends in that stuff with your bare hands!

The glands are pulled into axial alignment with the fitting when the nut is tightened, so there can't be too much fudging. Next is the auto-fill for the boiler with the solenoid in the line...

...and the connection from the solenoid to the inlet.  

This one was done using 8mm line, which was far easier and more pleasant to work with than the 10mm. Next time, I will use only 8mm 'cause life is too short. 

Now the really fun part :)

After cleaning the parts, I put little flux on the joint and a ring of the filler metal...

...and use a reducing flame (less oxygen than gas to avoid oxidizing the metals) to heat up the parts. Once the flux melts completely showing that the parts have reached temperature, the silver filler material flows into the joint perfectly. Mustn't forget to thread both nuts on the line because otherwise you are just starting over.

Plumbing part 4 - fill reservoir and water inlet

Cutting the copper tubing can be done with a pipe cutter, but this pinches the annealed tube too much as these small diameters.
I prefer to cut with a mitre and an x-acto micro saw. This method allows you to cut extremely precisely and to remove a tiny section from the end, which is difficult to do with a regular pipe cutter.

I mounted the custom bending dies I made on a cheapo 4" machinist vise. Somehow it reminds me of the critter from Alien. 




























Starting with a roughly 2.5" radius bend made with the regular tool, the custom bender can tighten up the radius to about 1.5".

This image of the line from the exit of the HX to the brew reservoir shows both a large bend used where there is space and a tighter one where there isn't.



























I got caught up in the process of making this bracket and it was all done before I realized that I hadn't taken any process shots:



























I cut off a 3" section of 1/8" x 2 1/4" cold-rolled steel and then cut that in two lengthways. Mark and centre punch the hole position, then drill using first a small bit to locate, a couple of intermediate sizes and then the finished sized bit. Then I did a "don't try this at home" by putting the 1/8" stock in my new 16 gauge rated (i.e. half the thickness) V-jaw metal brake. It is [i]just [/i]strong enough to bend the inch-wide piece of material - any wider and it would be hammer time. The V-jaw makes a nice sharp bend - close to the material thickness in radius.

Here is the bracket with the 3/8 BSPP parts it will support: the line in and the two feeds for the HX and boiler. 

Frame part 3 - LRFs and more plumbing

Before I go on with the plumbing, I think we need to get LRF equipped. I haven't sourced the final LRFs yet, so I looked through the LRF drawer and found some temporary ones. First, drill and tap some holes in the corner plates.

I have a little set of blocks with holes sized exactly for the tap that serve as guides to keep the holder perpendicular to the workpiece.

Not the best photo, but we are now officially Little Rubber Feet equipped. 

First up for plumbing is the sump. This plastic part is a huge improvement over the cast-metal one in both of my machines. Both of those are tiny and often silt up with grounds. Appart from being perhaps eights times the size, this one also has a large outflow.

A quick hole in the side and the expansion valve can be attached. I'm not going to bolt the sump in place until I have the rest of the lines sorted out.