We replaced what looked to be original thermostats for three zones of radiant ceiling heat in 2008. They were King Electric ESP230's which are for double pole, 240v, 22amp. Then about a year later they started to act up. King says it was algorithm issues and replaced them twice! Now two years later one is acting up. Two of the three zones are on 20 amp brakers each and one is on 30 amp breaker all of which are 240v. We like the programmable features of this thermostat and the fact you can turn it off completely but we really don't like the poor reliability and potential hazard it may cause since when it acts up they heat up way beyond temp setting. This last time even the on light wasn't on and it was set at 69 degrees and the room was like 80d degrees. It wasn't till I shut off the breaker did it stop rising. My fear is that I am not home and this happens again with another one and it will heat up the ceiling where it cracks it or burns up the system or causes fire. We are thinking about replacing the ESP230's with Lux ELV4 instead since I am sick of fighting with King Electric on this and these units are so faulty. I notice Lowe's is selling them and they didn't have review section operational. Also selling on Amazon.com and no reviews?? One of the owners, Dean, explained it had to do with bad algorithm and had the last set tested before he shipped them which I asked for since what is the point replacing bad ones with bad ones. Right now I feel he doesn't understand it enough to know how to test it properly. I just left a message this morning and no word back yet and have been waiting all day. Any suggestions as to a good programmable double pole thermostat that we can replace the ESP230's for this situation with this much amps and volts? I see Lux warranties their units for 5 years!
Also could use advise on how to test each zone to see how many amps each radiant zone actually draws with a Flute multimeter.

Try this one:

Honeywell TL8230A1003 Digital Programmable Line Voltage Thermostat With Pre-Set 7-Day Program (http://www.honeywell-thermostat.com/honeywell/TL8230A1003-thermostat.html)

Honeywell is the best.

You cannot use a multimeter to measure AC amps. Need something similar to this:

Amprobe Test Tools (http://www.amprobe.com/cgi-bin/pdc/searchprod.cgi?category=188&type=elec&tid=1&action=search)

Thanks for your response. I have already looked at that Honeywell model and even called Honeywell about it and found out it was rated for only 15 amps which maybe too low for the two 20 amp breakers for two rooms and one 30 amp breaker for other room

I still need to check how much of a load each zone actually uses on each breaker. Told that even if breaker was using 15 amps and thermostat max is 15 amps that is cutting it close. Any commercial thermostats that can handle bigger loads than 22 amps

Thanks for the heads up on the digital amp clamp multimeter.

Residential heating circuits, due to the deratings set forth by the National Electric Code, are typically 20 amp, and limited to 16 amps of load.

This is why Honeywell are all rated 15-16 amps.

Circuits loaded more than 16 amps will use a low voltage stat that will control a switching relay with contacts rated for a higher loaded circuit.