McElroy Discussion Forums

I have a couple of heaters that start to heat up and then shut down. Both the red and green LED lights flash at the same time. I have changed boards and I still have the same problem. Any ideas?

A couple of things to check would be the jumpers (must be set for the proper voltage) and the inputs to the board. If an RTD is shorted, it may cause the error mode to kick in. Go through the standard troubleshooting routine to check all components, and I think you will find the issue.

There are three things that will send the board into error mode.
1. RTD is open circuit
2. RTD is short circuit
3. Heater could not reach at least 300°F within 20 minutes

If the heater isn't reaching temperature, check the resistance of the elements, the voltage supplied, and the voltage supplied under load. An issue with any of these could cause situation 3. As John said, the standard troubleshooting procedure should find the issue.

It doesn't seem to do it when we are in the shop. so I dont think it's the element or rtd. Maybe my generator sucks?

Lol. My professional opinion is that perhaps as you put it, "Your generator sucks." But that statement may be a bit broad.


Check the voltage with and without load. It should be within 10% of 120vac or 240vac (depending on the heater you are using) when under load. This is an easy check to see if the generator has the power to keep up. If you don't have a meter, you can sometimes get any idea how the generator is doing by listening to it when the heater cycles on. If it bogs a bunch, then it should be checked with a meter. Also, if the voltage on the generator is set wrong such as too low or 120vac for a 240vac heater, it won't heat up quickly and it may never make it to proper temperature.

Good luck!

P.S. Hit the generator with a big hammer. Sometimes it helps. If not, get a backhoe and hit it with that.