Controller - Part 1 - Enclosure Preparation
Introduction
So to make this whole system work, some sort of electronic controller is necessary. It seems a lot of folks are going the electric route, and there is a plethora of information out there on electronic controllers for electric breweries. Since I am using gas, I had to adapt most of what I could find for my particular application. The controller was fairly simple to put together. After all, it’s just two thermostats, two thermometers, two switches for the pumps, and a master power switch. It just takes a bit of work to make it work the way you want it to. For part 1, I will get into all the parts that are needed, and getting the cabinet ready for installation of all of the components.
The cabinet is a simple metal enclosure that seals up water tight. I used a 16” x 16” x 12” deep box. Some use 8” deep, I found that the 12” deep box gave me a little more room to work with. You might be able to squeeze it all into an 8” box, it really comes down to if you can stand the extra 4” of depth when its mounted. I got my box on eBay, and it ran around $100. It came with all the mounting hardware and the back plate. You will need a back plate, so make sure that whatever you buy has one.
Basic electric components needed are 7 switches (5 need at least one NO contact, 2 need both one NO and one NC contact), 2 110 VAC lamps to indicate pumps are on, 1 110 VAC lamp to indicate power is on to the controller, and 2 24 VAC lamps to indicate that the gas valves are commanded open. I got an integrated audible alarm and lamp that operates on 110 VAC, you can opt for a separate lamp and horn. For my setup I used a 7.5 amp circuit breaker, push pull type. You don’t want the kind you use in your circuit breaker panel in your house. Rather you want a marine/aviation type.
Of extreme importance to mention here is that this controller is designed for use with two of the very common 1/20 HP pumps that are out on the market. These pumps draw less than 2 amps each, so if both are running you are getting under a 4 amp draw from the pumps which is in addition to the rest of the electrical components. A 7.5 amp breaker is sufficient for this set up. If you are using one of the bigger pumps that are not commonly used by homebrewers (lord knows what you were able to scrounge used on the cheap so I need to mention this caveat), you need to alter the design of the circuitry to account for the higher current draw. Since these are usually used by breweries (read professionals with commercial set ups), I will not cover their use here.
I used proportional integral derivative (PID) controllers for my temperature controllers. These are glorified thermostats. The reason I chose PIDs over Love controllers is that you can get them for half the cost. It is imperative that you get RELAY type output PIDs. Two different types are made. The first will provide its own power output when it commands heat. This is usually 110 VAC that is pulled from the 110 VAC input to the controller for operation. Electric breweries generally use this type as this output goes to the solid state relay that provides the current to the heating elements. Since we are using gas and 24 VAC gas valves, we need PIDs that pass the voltage we provide to them thru when heat is commanded. This way we get 24 VAC to the gas valves instead of 110 VAC that will melt their coils. If you are shopping online for them, the type we are using is typically the RNR type.
To get the 24 VAC for the gas valve control we need to get a step down transformer that takes in 110 VAC and puts out 24 VAC. These are very common as almost any gas appliance has one and they are a high replacement item. They go for less than $20. We need to get a contactor that will act as the on off switch for the controller. All a contactor does is control power. You can’t run high current through the measly switch that you mount to the panel to turn things on and off. What you run through this switch is the control voltage that is wired up to the coil on the contactor. When the switch is flipped, it provides current to the coil, which becomes energized and turns into an electromagnet. This closes the contactor and the contactor now passes the higher current power into the electronics.
A nifty thing that you can add is a safe start circuit control for the box (I didn’t come up with this, all credit goes elsewhere). This prevents the box from being powered up if the pump switches are turned on. Since running the pumps dry will destroy them, you don’t want them to accidently come on when the main power switch is turned on. To create this circuit, a small 8 pin relay and base are required.
All the wiring in the box is 14 gauge THHN type stranded wire that is readily available at HD or Lowes. I needed 50 feet of white, 100 feet of black, and 50 feet of green. Also, I needed 25 feet of both blue and yellow 16 gauge THHN stranded wire for the secondary (24 VAC) circuits.
A short digression on wiring. 14 gauge wire is good for up to 15 amp circuits. 16 gauge should handle no more than 10 amps. Gauge numbers are counterintuitive – the bigger the number the smaller the wire. Our whole box runs on less than 7 amps, so we could put 16 gauge wire on everything. However, if you ever want to upgrade or change anything, you would then need to rip it all out and rewire. The cost difference is negligible here, so it is advisable to just use the 14 gauge. The last little bit is about the circuit breaker. Circuit breakers protect wiring, not the stuff attached to the wiring or the person who accidentally touches a hot wire. The circuit breaker prevents excess current from going into the wire, which if exposed to more current than it can handle would effectively become a light bulb filament. It would burn and catch fire and generally do things that you don’t want it to do. Thus, with the 7.5 amp breaker and the 14 gauge wiring, we are really on the safe side here.
The last two things I picked up were a timer and a temperature display for the chilled wort coming out of my wort chiller. I will admit, I got a steal on the temp display, just got really lucky with my timing on eBay. It is really hard to find a panel mount display that does Fahrenheit. If you get stuck, you can always just use a PID. They are cheap and will do a fine job of displaying temperature.
The rest were small items that you can get at Radio Shack or on various websites. I used a few 8 position barrier strips (or terminal blocks) coupled with 8 position jumpers where necessary, self-adhesive cable holders, a ton of zip ties, and a ton of spade connectors (14-16 gauge, 4-6 stud). You also need wire strippers and a crimper, as well as a pair of dykes (diagonal wire cutter). And the final items – 2 12” stainless handles and 2 9” stainless handles, both 1.375” high.
Not to forget the input/output connectors, you will need a 3 terminal twist lock with male pins for input power, two 3 terminal twist lock with female for pump power output, 2 XLR with female for gas valve power output, and 4 XLR with male pins for thermocouple inputs. As a general rule of thumb, anything that has or can have power should be female, and anything receiving power should be male. Think of the wiring in your house. The outlet is female, the plug is male. On an extension cord, the part that plugs into the wall is male, which then energizes the cord, and the open end is female. This is to prevent accidental electrocution.
Prep work
Take the door off of the enclosure you have. Mark out your panel layout. My box was labeled 16” x 16” but actual dims were 15.5” x 15.5”. Measure your box when you get it to make sure of the size of the door. Your panel layout should make sense to you. Pay attention to the size of the stuff you are mounting to the door. All the items need clearance on the back side. Ensure you haven’t set yourself up for an interference condition with any of the connectors you will install on the bottom of the box, or with any items adjacent to each other on the door. If you have a 12” deep box you shouldn’t have to concern yourself with interference between door mounted items and items mounted on the back plate, there will be at least an inch or two between them. I can’t speak for the 8” deep box.
Build out
Once it is all laid out, start cutting. The holes for the switches and lamps should be 7/8” holes and I used a step bit to drill them. To use the step bit, its best to take either electric or metal tape and wrap it around the bit at the size one step above the one you are drilling to. This way you have a quick visual reference for when you have your correct diameter and don't drill too big of a hole. The holes for the PIDs can be cut using a jigsaw. Be careful when cutting these. The mounting clips for some of the DIN sized items are very tight. If you cut a hole just a little too big you won’t cover it up with the bevel that runs around the item. For that reason, its best to cut it just a bit tight (like on the inside of the line you mark), then use a file to open it up where you need to. To get the cuts started, drill a hole in the cut out area using a bit that is slightly larger than the jigsaw blade.
For the switches and lamps, they have “keys” on them that need little grooves cut around the holes. Take a look at the back side of them and you will see what I mean. Very easy to cut the tiny grooves, it can be done either with a file or with the jigsaw. Again, just be careful to not cut too much. Lastly, drill the holes for the screws that will mount the handles on the door and the bottom of the box. Be sure to avoid the seal on the door and don’t drill thru it.
The electrical connectors on the bottom are pretty big. Some folks have recommended using hole saws. They are expensive. I just used the jigsaw and cut it out bit by bit. Drill a hole in the center of the cut out area, and cut a straight radius to the edge of the cut out area. Do this again and again, at about 30 degree increments, around the whole circle. Then with a little work you can cut along the diameter and get a pretty decent circle. Lay in the connector and mark the holes for the mounting screws. Drill those out and either use self-tapping sheet metal screws or do what I did and use #6 or #8 machine screws, lock washers and nuts. For the XLR panel mount connectors, I ended up connecting them with rivets. At first I had tried the screws, but it was too tight to get nuts on them. However, don’t rivet them at this point – just drill out the holes so that the rivets will be usable on them.
Take the back plate out of the box. Lay out the items you will be connecting on the box. These should be a few of the barrier strips, the contactor, the 8 pin relay base, and the transformer. Not a whole bunch, but that back plate will become really busy with the wiring and all that will run on it. I installed the barrier strips using the self-adhesive cable mounts and zip ties. For the other items, I drilled holes in the back plate and put screws and nuts thru to attach them. You could optionally drill and tap the holes in the back plate and omit the nuts. Totally up to you and how motivated you are.
Once everything is drilled, cut, filed, fit checked, etc, on the bottom and front of the box, it’s time to paint it. The box is steel, and by cutting and drilling you have exposed some edges to the environment, so you need to restore the surface protection. I used hammered effect paint on it, you don’t have to, but you can. At a minimum you need to just touch up the areas that you cut or drilled. At a maximum you can make it any fancy color or finish effect you so desire. I taped everything up from the inside so that the paint would just stay on the exterior of the box, though it wouldn’t be the end of the world if you got some overspray in the box. Again, this falls up to whatever direction you want to go.
After the paint dries, it’s time to install everything. Go ahead and put all of the components in their places and install them. Nothing will be wired up at this point, but to start the wiring you need to have all the components in their place. Don’t overtighten the switches or lamps, the threads are plastic and will strip really easily.
That about sums up part 1 of the controller, part 2 will get into the wiring and hook up of the box.
So to make this whole system work, some sort of electronic controller is necessary. It seems a lot of folks are going the electric route, and there is a plethora of information out there on electronic controllers for electric breweries. Since I am using gas, I had to adapt most of what I could find for my particular application. The controller was fairly simple to put together. After all, it’s just two thermostats, two thermometers, two switches for the pumps, and a master power switch. It just takes a bit of work to make it work the way you want it to. For part 1, I will get into all the parts that are needed, and getting the cabinet ready for installation of all of the components.
The cabinet is a simple metal enclosure that seals up water tight. I used a 16” x 16” x 12” deep box. Some use 8” deep, I found that the 12” deep box gave me a little more room to work with. You might be able to squeeze it all into an 8” box, it really comes down to if you can stand the extra 4” of depth when its mounted. I got my box on eBay, and it ran around $100. It came with all the mounting hardware and the back plate. You will need a back plate, so make sure that whatever you buy has one.
Basic electric components needed are 7 switches (5 need at least one NO contact, 2 need both one NO and one NC contact), 2 110 VAC lamps to indicate pumps are on, 1 110 VAC lamp to indicate power is on to the controller, and 2 24 VAC lamps to indicate that the gas valves are commanded open. I got an integrated audible alarm and lamp that operates on 110 VAC, you can opt for a separate lamp and horn. For my setup I used a 7.5 amp circuit breaker, push pull type. You don’t want the kind you use in your circuit breaker panel in your house. Rather you want a marine/aviation type.
Of extreme importance to mention here is that this controller is designed for use with two of the very common 1/20 HP pumps that are out on the market. These pumps draw less than 2 amps each, so if both are running you are getting under a 4 amp draw from the pumps which is in addition to the rest of the electrical components. A 7.5 amp breaker is sufficient for this set up. If you are using one of the bigger pumps that are not commonly used by homebrewers (lord knows what you were able to scrounge used on the cheap so I need to mention this caveat), you need to alter the design of the circuitry to account for the higher current draw. Since these are usually used by breweries (read professionals with commercial set ups), I will not cover their use here.
I used proportional integral derivative (PID) controllers for my temperature controllers. These are glorified thermostats. The reason I chose PIDs over Love controllers is that you can get them for half the cost. It is imperative that you get RELAY type output PIDs. Two different types are made. The first will provide its own power output when it commands heat. This is usually 110 VAC that is pulled from the 110 VAC input to the controller for operation. Electric breweries generally use this type as this output goes to the solid state relay that provides the current to the heating elements. Since we are using gas and 24 VAC gas valves, we need PIDs that pass the voltage we provide to them thru when heat is commanded. This way we get 24 VAC to the gas valves instead of 110 VAC that will melt their coils. If you are shopping online for them, the type we are using is typically the RNR type.
To get the 24 VAC for the gas valve control we need to get a step down transformer that takes in 110 VAC and puts out 24 VAC. These are very common as almost any gas appliance has one and they are a high replacement item. They go for less than $20. We need to get a contactor that will act as the on off switch for the controller. All a contactor does is control power. You can’t run high current through the measly switch that you mount to the panel to turn things on and off. What you run through this switch is the control voltage that is wired up to the coil on the contactor. When the switch is flipped, it provides current to the coil, which becomes energized and turns into an electromagnet. This closes the contactor and the contactor now passes the higher current power into the electronics.
A nifty thing that you can add is a safe start circuit control for the box (I didn’t come up with this, all credit goes elsewhere). This prevents the box from being powered up if the pump switches are turned on. Since running the pumps dry will destroy them, you don’t want them to accidently come on when the main power switch is turned on. To create this circuit, a small 8 pin relay and base are required.
All the wiring in the box is 14 gauge THHN type stranded wire that is readily available at HD or Lowes. I needed 50 feet of white, 100 feet of black, and 50 feet of green. Also, I needed 25 feet of both blue and yellow 16 gauge THHN stranded wire for the secondary (24 VAC) circuits.
A short digression on wiring. 14 gauge wire is good for up to 15 amp circuits. 16 gauge should handle no more than 10 amps. Gauge numbers are counterintuitive – the bigger the number the smaller the wire. Our whole box runs on less than 7 amps, so we could put 16 gauge wire on everything. However, if you ever want to upgrade or change anything, you would then need to rip it all out and rewire. The cost difference is negligible here, so it is advisable to just use the 14 gauge. The last little bit is about the circuit breaker. Circuit breakers protect wiring, not the stuff attached to the wiring or the person who accidentally touches a hot wire. The circuit breaker prevents excess current from going into the wire, which if exposed to more current than it can handle would effectively become a light bulb filament. It would burn and catch fire and generally do things that you don’t want it to do. Thus, with the 7.5 amp breaker and the 14 gauge wiring, we are really on the safe side here.
The last two things I picked up were a timer and a temperature display for the chilled wort coming out of my wort chiller. I will admit, I got a steal on the temp display, just got really lucky with my timing on eBay. It is really hard to find a panel mount display that does Fahrenheit. If you get stuck, you can always just use a PID. They are cheap and will do a fine job of displaying temperature.
The rest were small items that you can get at Radio Shack or on various websites. I used a few 8 position barrier strips (or terminal blocks) coupled with 8 position jumpers where necessary, self-adhesive cable holders, a ton of zip ties, and a ton of spade connectors (14-16 gauge, 4-6 stud). You also need wire strippers and a crimper, as well as a pair of dykes (diagonal wire cutter). And the final items – 2 12” stainless handles and 2 9” stainless handles, both 1.375” high.
Not to forget the input/output connectors, you will need a 3 terminal twist lock with male pins for input power, two 3 terminal twist lock with female for pump power output, 2 XLR with female for gas valve power output, and 4 XLR with male pins for thermocouple inputs. As a general rule of thumb, anything that has or can have power should be female, and anything receiving power should be male. Think of the wiring in your house. The outlet is female, the plug is male. On an extension cord, the part that plugs into the wall is male, which then energizes the cord, and the open end is female. This is to prevent accidental electrocution.
Prep work
Take the door off of the enclosure you have. Mark out your panel layout. My box was labeled 16” x 16” but actual dims were 15.5” x 15.5”. Measure your box when you get it to make sure of the size of the door. Your panel layout should make sense to you. Pay attention to the size of the stuff you are mounting to the door. All the items need clearance on the back side. Ensure you haven’t set yourself up for an interference condition with any of the connectors you will install on the bottom of the box, or with any items adjacent to each other on the door. If you have a 12” deep box you shouldn’t have to concern yourself with interference between door mounted items and items mounted on the back plate, there will be at least an inch or two between them. I can’t speak for the 8” deep box.
Build out
Once it is all laid out, start cutting. The holes for the switches and lamps should be 7/8” holes and I used a step bit to drill them. To use the step bit, its best to take either electric or metal tape and wrap it around the bit at the size one step above the one you are drilling to. This way you have a quick visual reference for when you have your correct diameter and don't drill too big of a hole. The holes for the PIDs can be cut using a jigsaw. Be careful when cutting these. The mounting clips for some of the DIN sized items are very tight. If you cut a hole just a little too big you won’t cover it up with the bevel that runs around the item. For that reason, its best to cut it just a bit tight (like on the inside of the line you mark), then use a file to open it up where you need to. To get the cuts started, drill a hole in the cut out area using a bit that is slightly larger than the jigsaw blade.
For the switches and lamps, they have “keys” on them that need little grooves cut around the holes. Take a look at the back side of them and you will see what I mean. Very easy to cut the tiny grooves, it can be done either with a file or with the jigsaw. Again, just be careful to not cut too much. Lastly, drill the holes for the screws that will mount the handles on the door and the bottom of the box. Be sure to avoid the seal on the door and don’t drill thru it.
The electrical connectors on the bottom are pretty big. Some folks have recommended using hole saws. They are expensive. I just used the jigsaw and cut it out bit by bit. Drill a hole in the center of the cut out area, and cut a straight radius to the edge of the cut out area. Do this again and again, at about 30 degree increments, around the whole circle. Then with a little work you can cut along the diameter and get a pretty decent circle. Lay in the connector and mark the holes for the mounting screws. Drill those out and either use self-tapping sheet metal screws or do what I did and use #6 or #8 machine screws, lock washers and nuts. For the XLR panel mount connectors, I ended up connecting them with rivets. At first I had tried the screws, but it was too tight to get nuts on them. However, don’t rivet them at this point – just drill out the holes so that the rivets will be usable on them.
Take the back plate out of the box. Lay out the items you will be connecting on the box. These should be a few of the barrier strips, the contactor, the 8 pin relay base, and the transformer. Not a whole bunch, but that back plate will become really busy with the wiring and all that will run on it. I installed the barrier strips using the self-adhesive cable mounts and zip ties. For the other items, I drilled holes in the back plate and put screws and nuts thru to attach them. You could optionally drill and tap the holes in the back plate and omit the nuts. Totally up to you and how motivated you are.
Once everything is drilled, cut, filed, fit checked, etc, on the bottom and front of the box, it’s time to paint it. The box is steel, and by cutting and drilling you have exposed some edges to the environment, so you need to restore the surface protection. I used hammered effect paint on it, you don’t have to, but you can. At a minimum you need to just touch up the areas that you cut or drilled. At a maximum you can make it any fancy color or finish effect you so desire. I taped everything up from the inside so that the paint would just stay on the exterior of the box, though it wouldn’t be the end of the world if you got some overspray in the box. Again, this falls up to whatever direction you want to go.
After the paint dries, it’s time to install everything. Go ahead and put all of the components in their places and install them. Nothing will be wired up at this point, but to start the wiring you need to have all the components in their place. Don’t overtighten the switches or lamps, the threads are plastic and will strip really easily.
That about sums up part 1 of the controller, part 2 will get into the wiring and hook up of the box.
Inside of the box looking down with the holes cut. Notice the small key marks for the XLR receptacles - these are intentional. Check the receptacles you have and make these small key cuts so that they go in smoothly. The nub on the RH wall near the front is a cover for a ground stud receptacle. You can remove this if you want. We will be using the ground stud on the LH wall near the top front.
Same thing, this time from outside the enclosure.
I removed the door to make things easier to work with. This shows all of the holes cut with the exception of the holes for the handles that I installed. When you mark and drill the holes for the handles, be careful to not hit the seal on the inside of the door. Also shown in this view is the hole left after removing the latch. This is the hole in the middle on the right that isn't quite a circle. Also - the switches have the same little keys on them as the XLR receptacles do. This photo doesn't show the key holes that I cut to accommodate the keys.
Same thing, from the inside of the door. Here you see the seal I mentioned before (the thick black rubbery thing around the perimeter of the door. In the top right corner is the door ground stud.
After paint, with the handles installed. You can see some of the components installed on the back plate as well. I got a little antsy and did that while waiting for paint to dry. My enclosure had a big hole cut in the top (you want it to be on the top as you need the solid side to cut holes in for your external connectors). It came with a foam seal and all the hardware to close it up. I did this after paint - if you paint it all together and ever do take this panel off, you will mess up your paint job unless you cut all the seams with an exacto knife before disassembly.
All the parts are installed. I didn't get a shot before finishing the controller, so just pretend that it isn't plugged in or turned on, at this point none of the guts are wired up yet anyway.