I just built it with my dad. It’s a simple three tier gravity system with two heating elements. But I do use a pump for the CFC. Will have the final bulk head welded on to the boil kettle ASAP for the returning wort, plus heavy water sealer on the wood. Can’t wait to fire it up. This will make home brewing so much more efficient.
Looks good, Will! 8)
Not sure you need a ball valve on the input side of the pump. With a mag pump you control the flow entirely with the output valve. Otherwise, the pump will likely cavitate and you won’t get a push through the counterflow chiller.
Looks great.
On a safety note, how do you fireproof the wood given the presence of open flames?
Yeah, the HLT burner is ok but you need to shield the platform your mash tun sits on. The heat wash from the kettle will toast that pretty quickly. You can get some 16-20 inch aluminum flashing from Home Depot that would work great.
Hacker is right, you do not want to restrict the input, as that can cause cavitation. You can throttle the output with no problems.
I would put some cement board or large tiles under the burners, but that is just me. You can feel the plywood and see it it gets hot.
On the side by the HLT, the suggested heat shielding is also something I would do.
Tiles and metal sheeting are my two ideas, gonna see whats available. Will the pump cavitate with the valve all the way open? I wasn’t using that one for back pressure. It’s always open all the way when the cfc is in use. I throttle it with the output side. And I do have a mounted fire extinguisher on the upper propane tank shelf.
Looks very practical. How do you like it so far?
Job well done!
I’ve got a wooden three tier, and it never really gets that hot under or near the burners. But for safety I use rimless baking sheets, the wood under them never even gets warm.
Cavitation is when the pressure of the fluid is lower than the pressure of the wort (or water or any other fluid). A small bubble forms, and then collapses when the pressure is greater down stream. The collapse can cause errosion to the metal on the pump, and should be avoided. Cavitation can happen to the propeller on a boat in the lake. Elevated temps make it even more likely.
Keeping the valve open will put full pressure on the pump inlet, which is good. Having the pump mounted lower is good, as you have more pressure head on the inlet. If you slowly close the inlet valve at some point you will hear a growling type noise from the pump, as it has started to cavitate.
Having the extinguisher handy is a good thing!
Thank you all for the good words and advice. Will let you know how it goes when I get it all ready brew this weekend.
Concrete board is my recommendation. It’s like drywall, but… well… concrete. It’s what they recommend to insulate flamable wall materials behind wood stoves in houses. I’ve also used it to reinforce under tile floors.
I’ll have to agree with Tom that the chances of the wood structure that the burners sit on catching fire is slim to none. I’ll also agree with dak that the area that is supporting the mush tun cooler is the most susceptible to any heat related issues. Concrete board would add a lot of weight. Metal flashing or similar thin sheet should be sufficient to “wick away” the heat. I can assure you, wood decking on roofs in the summer time see a lot more heat than the stand ever will, Will . . 
Hacker - I alway err on the side of caution. You and Tom are probably right. Checking the wood while in operating the system would be the way to go.
Jeff . . Agreed!
I have a propensity to over design and overkill on most everything. :D
That’s not a bad thing. I was also looking at some 12 in by 12 in terra cotta tiles that would sit under both burners. There over an inch thick. I don’t see a need to put anything under the mash tun for it is insulated on the bottom already.
Went off with out a hitch. Did up a Scottish wee heavy for Christmas.