The Doghouse Brew Rig Build – Part Two “The Gas System”
|May 10, 2012||Posted by 2nobledogs under Equipment, The Doghouse|
Ok, in part 2 of The Doghouse Brew Rig Build we are going to discuss the different components of the gas system and how it all goes together. The first thing you should know is ALWAYS BE SAFE! Putting the gas system together is not difficult but if you are not completely comfortable tinkering with gas lines you may want to get some assistance. This posts assumes that the main frame and the burner mount frame has already been assembled. If not, refer to back to part one of The Doghouse Brew Rig Build here.
The gas system is made up of components that will transfer the gas from the tank to the burner. Sounds simple right? Well, not exactly but, if you keep that thought in mind it helps you visualize how things need to go together.
Now that you have decided to tackle the gas system you need to decide whether you are going to use a combination of High pressure and Low pressure OR just use all Low pressure. This system utilizes furnace valves to regulate the burners and these furnace valves only operate under low pressure. I used both high pressure and low pressure (high pressure for the boil pot and low pressure for the others) on my system. I wanted high pressure on the boil pot so I could get it to a boil faster. If you use an all low pressure system some of the components listed below are not needed. I could get into the differences between high and low pressure systems but I’ll save that for another post. You just need to decide which one you want to use.
There are many variations in the components that you can use. For this post I’m only going to discuss what I used on the Doghouse which is a combination high and low pressure system.
- ½” Black Pipe and fittings
- 2 – 24” length
- 1 – 6” length
- 3 – 2” length
- 2 – ½” x ½” Tees
- 4 – ½” 90° Bends
- 1 – High Pressure regulator hose w/ tank connection
- 3 – ½” Gas ball valves
- 2 – Low Pressure Regulators
- 3 – BG-14 Banjo Burners
- 2 – Low Pressure Orifices (converts burners to low pressure)
- 5 – Flexible gas lines
- 2 – Honeywell Furnace Valves
- 2 – Honeywell Pilot Lights
- 2 – Honeywell Termocouples
- 5’ – ¼” flexible copper tubing
- Variety of brass fittings to connect everything up
- RectorSeal (dope) or Teflon tape (made for gas)
The first step is to assemble the gas manifold (I’m sure I probably don’t need to point this out but I’m going to anyway, USE RECTORSEAL OR TEFLON TAPE AT ALL OF YOUR CONNECTIONS). It is constructed out of ½” black pipe that you can pick up at any hardware store. Do not use the gray or galvanized pipe. Assemble the pieces so you have a fitting attached to one end to accept the gas line from the tank. Then connect the remaining pipes and fittings so you have 3 outlets to feed the burners. Attach a ½” gas ball valves to the black pipe at each outlet. Now you want to attach a low pressure regulator to the 2 outlets that will ultimately attach to the burners under the Hot Liquor Tun (HLT) and the Mash Liquor Tun (MLT). One my system they were the middle and far right burner. Now connect a flexible gas line to each low pressure regulator and one to the outlet that will go to the burner for the boil pot (far left on my system). Connecting all this up can be a bit confusing because of all the different fittings and thread sizes involved. Don’t let it bog you down. You will be using a ¼”, 3/8”, or ½” fitting. With either a flared end or NPT thread. The easiest thing to do is lay out each of your components and then draw a rough sketch that illustrates the sequence that they will be connected. Label each end of the component as to what size fitting is needed to make that connection.
Then you can take that sketch to Lowe’s or HD and get the folks there to assist you. I found that they were always more than willing to help and once you told them it was for a brew rig they made it their personal mission to make sure they got you what you needed. One thing to note: if you use appliance gas lines as I did (yellow lines on my rig) they will come with several fittings. They will also come with a safety valve which will keep the gas from backing up in the system. Seems like a good idea right? So, when you lay out the components you probably already have a few of the fittings that will work. One more thing on the appliance gas lines, the safety valves only work on the low pressure lines. They will not work for the boil kettle burner.
Now you need to change out the high pressure orifices to low pressure orifices on your HLT and MLT burners. Once you’ve completed that, connect the flexible gas line from your manifold directly to the burner orifices. Now you can connect your propane tank to the manifold using your high pressure regulator line. Notice we have not connected the furnace valves yet. The reason for this is because those valves will not operate properly without the controller telling it what to do. The controller is part of the main control panel which we will get into in a future post.
Check for Leaks
Now we need to check for leaks. With all the ball valves closed on the manifold, slowly open the propane tank valve. This will fill the manifold with high pressure gas. Listen and smell for any leaks. If you do smell or hear something try to isolate it by sound. If that does not work spray soapy water around the joints and look for bubbles. Once you’ve isolated the leak, take that joint apart, rewrap it and tighten it back up. Repeat that process until the situation is corrected. Once the manifold has been check, move on to each individual outlet. Open each ball valve one at a time and listen/smell for leaks. Correct as needed. This is a little more difficult on the boil pot burner because there is no valve on the high pressure orifice as there are on the low pressure orifice. You will need to use soapy water as soon as you open the ball valve. At this point you should not have any leaks all the way to the burners. Now you can test the burners themselves. Again, open each ball valve one at a time and fire the burner. You should see a blue flame about 1.5” to 2” coming out of the low pressure burners and a 1” blue flame blasting out of the high pressure burner. You may need to adjust the air openings to get the proper flame.
Now attach the manifold to the main frame. I used single screw conduit hangers from Lowes.
Furnace Valve and Pilot Assembly
Once you are satisfied that everything is working properly to this point you can remove the burners from the gas lines and prepare to connect the furnace valves. My furnace valves are connected to the “burner frame” as opposed to the actual brew rig frame. You can do it either way just keep in mind you want to minimize the stress on the gas line connections into the valve itself. To me it made more sense to keep the relationship between the valve and burner constant in the event I needed to adjust the height of the burners.
The furnace valves I used were Honeywell. They are set up to be used on a natural gas system. No big deal, these are easily converted to LP gas using the included conversion kit. Make sure you follow the instruction that come with it but it is almost as simple as replacing a light bulb. Now your valve is set up but don’t attach it to your frame yet. You still need to attach the pilot light and thermocouples.
The pilot light and thermocouple need to be attached to the burner so it can fire properly. The pilot light I used comes mounted on an “L” shaped bracket. I straightened the bracket out and then mounted it on the bottom of the burner with the light itself located in between to openings on the burner. I used tiny self-tapping screws for the connection. I also coated the threads with Rectorseal.
If you have not already mounted the burners, go ahead and mount them to the burner frame. Then place the furnace valves in the general location of where they will be mounted on the frame. Cut a piece of ¼” flexible copper line about 18” long (this may vary on your rig) to connect the pilot light to the furnace valve. Make sure not to damage the end. De-bur and clean the ends and connect to the pilot light with the compression fitting included with the light. Now, very gently, bend/form the line around the burner and back to the furnace valve being careful not to crimp the line (pipe benders can be used for this step). Connect the line to the furnace valve using the compression fitting included with the valve. Next, uncoil the copper line attached to the thermocouple and attach to the furnace valve. This has very specific tightening instructions so make sure you follow them precisely or your valve won’t work. I found this out the hard way. Now you can mount the valve to the burner frame.
At this point you should have you manifold mounted to the main frame, and the burners and furnace valves mounted to the burner frame. Now just connect the remaining flexible gas lines and your there! Woohooo!
Unfortunately, you can’t fully test it until you get your controller assembled. In part three of this build post I will talk about how to assemble your controller. That’s it for now. Please let me know if you have any comments or questions. Good luck with your build and check back soon.
Also, it has come to my attention that the detail needed to fully explain how all this goes together is difficult to include in a blog post. I have been kicking around the idea of putting together a “How to” manual that will explain and describe things in full detail with plenty of images to help bring things into context. If this is something you would be interested in please let me know.