I called Johnson Control and they told me that the A-419 is OK for 15 amps. I have a similar arrangement with two 1500 watt elements on two seperate circuits. One is just on/off, the other is controlled with the A410. I use both to bring up to mash temp. Then the A419 controls your mash temp nicely with just the one element. Then both full on again to bring up to boil.