Two Heaters On A Double Socket

All heaters have a temperature sensor.

They also cycle on and off depending on the control setting and to prevent overheating.

It is possible that the heat from one heater fooled the other heater's sensor into thinking the room had reached the appropriate temperature or the heater was over-heating.

"Fooled"? The thermostats were simply measuring the room temperature.

Actually not all heaters have temperature sensor. There are quite a few manual heaters out there, and all the heating elements I design have no temperature sensor built into them. We use a seperate probe for monitoring and controlling temperature.

A good start, nearly enough information for a solution.

What type heaters?

what type control?

temprature range?

deadband?

Sorry, the questions can never be clear enough.

The 2 heaters heat 2 individual water tanks. They both have individual thermostats. The first water tank cycled around 70 degrees (plus minus 5 degrees) for quite some time. When the second water tank was switched on, the first heater switched off for 3 hours which resulted in a drop of 20 degrees.

Thanks a lot, Jurgen

Very strange. Did you smell smoke? If you are referring to a normal 120vac outlet? 1300 watts is almost the limit of what you could get on a 15 amp circuit (1800 watts). Even a 20 amp rated circuit would only give you 2400 watt capacity so you might have to change your plan or expect more dire consequences than one heater not heating.

To reinforce what rcapper has said, we had 2 fan heaters running off a double socket in the office until we unplugged one to use the socket for something else & noticed how much the plastic face plate had heated & distorted.

We are using 240vac socket on a 12 amp circuit (2880 watts). Is that not enough for 2 times 1300 watt heaters?

Thanks, Jurgen

If you were seeing an overvoltage theres a small chance you could have been loading your circuit to capacity, but I don't know why it would make one heater stop working properly.

Does the problem stay with 1 heater?

The 1300 watt x 2 heaters should draw 10.8 amps at 240V (assuming they are 240V heaters... if the heaters are 1300 watt at 220V, then running them at 240V will put your amperage up around 12.9 amps.)

I frequently see heater issues, and most problems seem to origoinate with faulty connections, faulty temperature sensor probes, or controls. If the temperature in the tank is 20 degrees below the set point of the thermostat then the thermostat is the first thing I'd check for integrity.

That should be adequate. Try turning them both on at the same time. If they both run until things warm up and then only one runs it is as indicated by other posters that the one with the lower set or calibrated thermostat will dominate. You could probably find a setting where they would both run, if they are settable. Otherwise you don't really need both to maintain temp once reached but you will still heat faster to get there initially.

How long is the run from your circuit breaker panel to the socket? It is quite possible that with a long run, the resistance in the cable is doing you in with the larger load. I will assume that you are using 14 gauge cable. If you increase the cable size to 12 gauge or 10 gauge, that might solve your problems.

Bill

Thanks for all your replies. What has happened is that I plugged the second heater in just at the time when the thermostat of the first heater switched off. So, the switching off of the first heater had nothing to do with the second heater. A subsequent trial proofed the above.

Thanks again, Jurgen