Harnesses
Introduction
Now that the stand, gas system, and controller are built, we need to put together the wiring and cords that will power it all and connect it all up.
During the discussion on chassis electric, we did the wiring for the pumps and the wiring from the gas valves to the disconnect we put together. In here, we are just going to talk about the main power cord, the cord that will go from the gas valve disconnect to the controller, and the RTD harnesses.
Prep work
For the main power cord, I picked up a power tool replacement cord at Home Depot or Lowes. It is a 12/3 wire. You can do 14/3 if you want, but since all your wiring in the box is 14 gauge, I would advise against a 16/3 wire. The replacement cord has a male prong for going into a standard household 110VAC outlet, and the other end is left with a black, white, and green lead for connecting to something. That something will be your plug that matches the main power in receptacle you bought for your controller. If you did the 4 pin 220VAC receptacle, get a 4 pin twist lock female. If you did 3 pin 110VAC, get a 3 pin twist lock female.
For the gas valve harness, I used an IP68 3 pin female connector. You will need 2 equal lengths of 18/2 thermostat/bell wire (mine are about 10 feet). Both wires run to the IP68 connector, and each wire has its own XLR connector to plug into the panel mount XLR receptacles for the gas valves.
The RTD harnesses are all 18/3 thermostat/bell wire. They are also about 10 feet long. They will go to XLR connectors, and the bell wire will be spliced to the RTD leads.
Build out
Main power cord
Pretty simple to do, just unscrew the thing, run the wire into it, strip the wire according to the instructions from the connector, and hook it up. Remember, black goes to the brass screw, white to silver, green (or bare copper) to ground. If you did the 220VAC setup, your black wire will go to X or Y, the same as you wired up in you receptacle in the controller. Once hooked up, screw the thing back together. Nice and easy.
Gas valve harnesses
On the female IP68 connector, we are going to wire up the same way we did on the chassis electric hook up. Gas valve 1 red to pin 1, gas valve 2 red to pin 2, and both whites to pin 3. At the other end, you are going to solder the XLR connectors to the wires. Unscrew the XLR connectors. Put the outer backshell on the wire first, then the inner backshell. Now strip about an inch of the outer insulation on the bell wire, exposing the red and white wires. Strip these between 1/4-1/2”. Make sure you solder the red wire to the same number pin as the blue wire is soldered to in your controller. I used 1 for blue, 2 for yellow in the panel, and 1 for red, 2 for white on the harness. After its soldered, put the pin piece into the outer shell (there are small grooves cut in the outer shell, and small tabs on the plastic piece the pins are mounted to, they need to align to go together), followed by the inner backshell, then screw on the outer backshell until it is tight. Don’t use tools, but tighten it down good by hand. Repeat for connector #2.
To know which is which, I put a wrap of electric tape and a zip tie on the harness for valve #1, and 2 wraps and zip ties on harness #2. You can do whatever you fancy here to segregate them, either by making one longer than the other, or using different color tape wraps, or put a piece of heat shrink on one, totally up to you. Once the connectors were on, I started at the outlet plug end and put small zip ties around both wires to make one harness. I did this at about 9” intervals the length of the harness until about a foot from the XLR connectors. This is totally optional, and serves no purpose other than to keep the two together and to keep them from getting jumbled up into a Christmas tree light style knot.
The RTDs
The RTDs come with small spade connectors on them. You will need to cut them off (where they are crimped on, not immediately at the sensor). Prior to cutting them off, make sure that the three wires are color coded! If they aren’t, and the only things that are color coded are the spade connectors, you are going to need to do them one by one to keep things straight. The 18/3 wire has red, white, and green (guess the manufacturer is Italian) wires in it. I treated the green like a second red. The RTD has 2 red and a white (sticking to my earlier color key for ease), so the bell wire red goes to RTD red 1, bell wire green to RTD red 2, and bell wire white to RTD white.
Inside the controller, the data wires used were two reds and a black. Same principle here. Inside the box I did red on 1, black on 2, and red on 3. On the XLR connector at the harness, I did red on 1, white on 2, green on 3. RTDs have some seriously small wires from them. Its like 24 or 26 gauge. I didn’t use strippers to strip them, my thumbnail did the job well. Just be really careful to not damage them. Put them together the same way you did the connectors for the gas valves. Where the bell wire needs to connect to the RTD wire, I used 18-22 splices. Yes, the RTD wire is smaller, but these will crimp down on it. Over these splices I did some heat shrink, followed by a layer of electric tape wrap and two zip ties to retain it all in one place. If you are putting heat shrink on, put it on the wire prior to splicing the two wires together or you will be cutting the splice you just did out to get the heat shrink on.
That about does it for your wiring harnesses and cords, were ready to power up and verify it all works right!
Now that the stand, gas system, and controller are built, we need to put together the wiring and cords that will power it all and connect it all up.
During the discussion on chassis electric, we did the wiring for the pumps and the wiring from the gas valves to the disconnect we put together. In here, we are just going to talk about the main power cord, the cord that will go from the gas valve disconnect to the controller, and the RTD harnesses.
Prep work
For the main power cord, I picked up a power tool replacement cord at Home Depot or Lowes. It is a 12/3 wire. You can do 14/3 if you want, but since all your wiring in the box is 14 gauge, I would advise against a 16/3 wire. The replacement cord has a male prong for going into a standard household 110VAC outlet, and the other end is left with a black, white, and green lead for connecting to something. That something will be your plug that matches the main power in receptacle you bought for your controller. If you did the 4 pin 220VAC receptacle, get a 4 pin twist lock female. If you did 3 pin 110VAC, get a 3 pin twist lock female.
For the gas valve harness, I used an IP68 3 pin female connector. You will need 2 equal lengths of 18/2 thermostat/bell wire (mine are about 10 feet). Both wires run to the IP68 connector, and each wire has its own XLR connector to plug into the panel mount XLR receptacles for the gas valves.
The RTD harnesses are all 18/3 thermostat/bell wire. They are also about 10 feet long. They will go to XLR connectors, and the bell wire will be spliced to the RTD leads.
Build out
Main power cord
Pretty simple to do, just unscrew the thing, run the wire into it, strip the wire according to the instructions from the connector, and hook it up. Remember, black goes to the brass screw, white to silver, green (or bare copper) to ground. If you did the 220VAC setup, your black wire will go to X or Y, the same as you wired up in you receptacle in the controller. Once hooked up, screw the thing back together. Nice and easy.
Gas valve harnesses
On the female IP68 connector, we are going to wire up the same way we did on the chassis electric hook up. Gas valve 1 red to pin 1, gas valve 2 red to pin 2, and both whites to pin 3. At the other end, you are going to solder the XLR connectors to the wires. Unscrew the XLR connectors. Put the outer backshell on the wire first, then the inner backshell. Now strip about an inch of the outer insulation on the bell wire, exposing the red and white wires. Strip these between 1/4-1/2”. Make sure you solder the red wire to the same number pin as the blue wire is soldered to in your controller. I used 1 for blue, 2 for yellow in the panel, and 1 for red, 2 for white on the harness. After its soldered, put the pin piece into the outer shell (there are small grooves cut in the outer shell, and small tabs on the plastic piece the pins are mounted to, they need to align to go together), followed by the inner backshell, then screw on the outer backshell until it is tight. Don’t use tools, but tighten it down good by hand. Repeat for connector #2.
To know which is which, I put a wrap of electric tape and a zip tie on the harness for valve #1, and 2 wraps and zip ties on harness #2. You can do whatever you fancy here to segregate them, either by making one longer than the other, or using different color tape wraps, or put a piece of heat shrink on one, totally up to you. Once the connectors were on, I started at the outlet plug end and put small zip ties around both wires to make one harness. I did this at about 9” intervals the length of the harness until about a foot from the XLR connectors. This is totally optional, and serves no purpose other than to keep the two together and to keep them from getting jumbled up into a Christmas tree light style knot.
The RTDs
The RTDs come with small spade connectors on them. You will need to cut them off (where they are crimped on, not immediately at the sensor). Prior to cutting them off, make sure that the three wires are color coded! If they aren’t, and the only things that are color coded are the spade connectors, you are going to need to do them one by one to keep things straight. The 18/3 wire has red, white, and green (guess the manufacturer is Italian) wires in it. I treated the green like a second red. The RTD has 2 red and a white (sticking to my earlier color key for ease), so the bell wire red goes to RTD red 1, bell wire green to RTD red 2, and bell wire white to RTD white.
Inside the controller, the data wires used were two reds and a black. Same principle here. Inside the box I did red on 1, black on 2, and red on 3. On the XLR connector at the harness, I did red on 1, white on 2, green on 3. RTDs have some seriously small wires from them. Its like 24 or 26 gauge. I didn’t use strippers to strip them, my thumbnail did the job well. Just be really careful to not damage them. Put them together the same way you did the connectors for the gas valves. Where the bell wire needs to connect to the RTD wire, I used 18-22 splices. Yes, the RTD wire is smaller, but these will crimp down on it. Over these splices I did some heat shrink, followed by a layer of electric tape wrap and two zip ties to retain it all in one place. If you are putting heat shrink on, put it on the wire prior to splicing the two wires together or you will be cutting the splice you just did out to get the heat shrink on.
That about does it for your wiring harnesses and cords, were ready to power up and verify it all works right!