[mcorrigan]

I have wired two Marley electric baseboard heaters (240v) to a Programmable Thermostat. The problem is, nothing is working…
Here are the stats:

BASEBOARDS
Baseboard #1 is 3 feet long, 3.1 amps & 750 watts.
Baseboard #2 is 4 feet long, 4.1 amps & 1000 watts.

WIRE & CURCUIT BREAKER
I am using 12/2 wire with ground, and connected to a double-pole 20amp circuit breaker. The black wire is connected to the double-pole 20amp breaker, and the white wire (labeled with black tape) is connected to the double-pole 20amp breaker.

THERMOSTAT
Honeywell RLV430 Programmable Thermostat

SETUP
Sequentially it goes, Main Electrical Box >>TO>> 1st Heater>>TO>>2nd Heater>>TO>>THERMOSTAT (all using 12/2 w/Ground wiring)

In the first heater, I have connected the white wires from both lines with one of the two connection wires on the left side of the baseboard. I did the same with the black wires and the other connection wire on the left side of the baseboard.

I did the same in second heater (white to white and black to black). The White and Black then lead to the Thermostat and connect with it there and terminate Ground to the metal box.

After wiring everything and turning the breaker ON, it seems like the breaker doesn’t stay in the ON position. It goes to a Neutral position (not ON or OFF) and nothing works. I even tested the Heater Line right above the box in this Neutral position and do not get a signal. I.E. It is not hot according to my tester.

Where should I start in troubleshooting this?! Any help you can provide would be appreciated.

Thanks,
MC

[labman]

You must have a short somewhere. That would cause the breaker to trip. Quite often they don't go all the way to off. Sometimes to reset them, you do have to turn them all the way to off, and then to on. With the breaker off, set your meter on ohms and check the resistance. It will be very low. Start disconnecting wires from the second heater and thermostat until you remove the low resistance. The circuit should be over 10 ohms.

The problem should be the thermostat. It sounds like it is shorting the 2 legs. You want power from one leg to have to flow through the thermostat and back to reach the heaters.

[tkrussell]

If I understand you correctly, at each heater all the blacks are connected and whites are connected.

If this is true, the circuit is not wired properly and the stat is shorting the circuit. Nothing is wrong with the stat. Well, at first, now it may be defective, since it is wired to short the circuit the contacts may be damaged.

The power feed needs to go to the stat first then to the heaters.

And since you have two wire cable in this sequence:
Sequentially it goes, Main Electrical Box >>TO>> 1st Heater>>TO>>2nd Heater>>TO>>THERMOSTAT , the stat will not work both heaters. Will need 3 wire between the two heaters.

Note in the diagram from the manual the supply wire goes to one wire of the stat FIRST, then to the heater.

[mcorrigan]

Thanks tkrussell,

I think I have it now... my only question now is how does the 3 wire connection fit in. What do I connect the 3rd wire to?

See the diagram below of my setup (or at least what it will be once I rewire the connections).

[tkrussell]

Nice job on the sketch. The red wire will connect to the load side of the stat, or at heater closest to the stat, and come back to the second heater. Disconnect that line feed at the heater, and connect the red.

See how you have the supply feeding both the stat AND the heater? The feed needs to feed the stat first.

[mcorrigan]

I am not sure if I follow you exactly. I have redrawn my diagram based on your last comments but am not sure if my drawing is correct (to what you were describing). I added letters to each connection to make it easier to describe.

"The red wire will connect to the load side of the stat (I?), or at heater closest to the stat, and come back to the second heater (G?). Disconnect that line feed at the heater, and connect the red.

See how you have the supply feeding both the stat AND the heater? The feed needs to feed the stat first. (A&B to E&F to I&J ??)


I thought I would need a connection between B&D as well, to complete the circuit.

FYI: I ran the heaters with the other set up (based on my original drawing- no 3-wire), and it seems to turn on but is not producing enough heat... it is warm.

I have shut off everything and need to figure out next steps.

Thanks in advance.
MC

[mcorrigan]

Here is the diagram.

[tkrussell]

Here I modified the wiring diagram as it should get connected.

[mcorrigan]

THanks- I will give it a go this week.

[mcorrigan]

This last diagram of wiring didn't quite work. I now get full power and heat to the Heaters. However, when I set the thermostat down to 40 to turn off the heaters, the heaters do not turn off. They just keep kicking out heat.

I went back and rechecked the wiring and everything seems to be according to the diagram... not sure what to do next.

My understanding of the two wires on the thermostat is that id doesn't matter which is connected to the 12/2 wires coming into the thermostat box.

Any other suggestions?


Thanks in advance.


MC

[tkrussell]

Has to work, unless the thermostat is bad, disconnect the two wires from the stat, correct does not mater which wire is which because it is a single pole switch.

Once the stat is disconnected, with the power on, and E & G wire opened the heat should be off, put E & G together the heat should come on. If this all happens, then the stat is defective.

This can be checked by either a continutiy tester, should have none across the two stat wires with the stat off, and should connect once the stat is turned up and closes at the temperature seeting.

Or, connect E to one stat wire, turn on the power, and use a voltage tester across the other stat wire to ground, should be zero volts with stat off, and read volts as the stat is turned up above the temperature setting.

If E is connected and you read volts across the other stat wire to ground as soon as the stat is turned on, then the stat is bad. The stat should not close until the setting is higher than the temperature of the room.

The diagram works with a single pole switch, which the stat is. Either the stat is bad, or there is a miswired splice.

[mcorrigan]

I returned the stat and installed a new one... it now works.

Thank you for the help! I definitely learned a few things along the way. I would definitely recommend this site in the future.

[Protek]

Thanks tkrussell,

I think I have it now...my only question now is how does the 3 wire connection fit in. What do I connect the 3rd wire to?

See the diagram below of my setup (or at least what it will be once I rewire the connections).

This is not correct. The heaters will be on all the time and the thermostat is probably tripping the breaker. Look at the diagram and you'll see the power coming straight into the heaters? There is no control. The power needs to feed first to the thermostat. Then, it will control the 240 vac out to the heaters.

[pops1389]

What you are trying to do is feed the two heaters in series, Two 110V heaters being fed from 220 V cct. The last diagram is okay if you remove the connection from B to F and reconnect B to D. there is no connection at F.

[pops1389]

If you are wiring 2 240 V heaters to the same 240 source then they have to be in parallel, with one side of the CCT going to the stat, the other side going to both heaters element the other side of the element goes to the other side of the 240 V CCT. G and C are connected together and connected to the Stat, H, D and B are all connected together. There is no connection between B and F.

[hfcarson]

Pops... you are aware this post is about 3.5 years old?

[tkrussell]

And the problem was solved:

I returned the stat and installed a new one... it now works.