JLD612 How To set to act as thermostat for On/OFF control?

Murphy
Posts: 3
Joined: Thu Dec 22, 2011 8:54 pm

JLD612 How To set to act as thermostat for On/OFF control?

Postby Murphy » Thu Sep 10, 2015 3:34 pm

I'm using a JLD612 to heat a 500 gallon tank of liquid to 150 degF. The tank is heated via a boiler system and hot water heat exchanger. The JLD612 simply turns the hot water pump on or off to achieve the right temperature.
My problem is that it cycles way too much and is going to shorten the life of the pump motor.

What I would like to do is set the JLD612 to act more like a thermostat where it turns off at the setpoint and would turn back on maybe 10 degrees lower or something.

How do I set the P, I, and D settings to achieve this? Or is it possible to just turn off the PID function?

I don't need the controller to learn, I just need it to turn off at the setpoint and turn back on at a set percentage lower.

laserdude
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Joined: Mon May 04, 2015 4:26 pm

Re: JLD612 How To set to act as thermostat for On/OFF contro

Postby laserdude » Fri Sep 11, 2015 12:14 pm

I'm not a JLD612 expert, but you might try adding some insulation to the temperature sensor. This should have the effect of adding some hysteresis which will reduce the pump cycling at the expense of greater temperature variation.

Another idea . . . Reduce the pump speed or switch to a lower capacity pump.

richiem
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Re: JLD612 How To set to act as thermostat for On/OFF contro

Postby richiem » Fri Sep 11, 2015 4:02 pm

This issue has been addressed here in the forum a number of times. The manual details exactly how to use the JLD 612 as a simple thermostat, which includes the ability to set the amount of hysteresis, ie how big a temp differential will occur before turn-on to reheat. Please read the manual for the Outy settings -- I don't remember which of them is the correct one at the moment and can't take the time right this minute to look it up, but the info is there. The correct setting disables the PID function, which would be useless for your application -- you are right to want a simple thermostat control function. Good luck.

richiem
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Re: JLD612 How To set to act as thermostat for On/OFF contro

Postby richiem » Sat Sep 12, 2015 12:05 am

Further notes -- Got a chance to look at the manual again -- you want to use Outy set to 3 (see figure 3 int he manual, the heating example); set AH1 to your SV (set value, where the heater turns off) and AL1 to your desired lower temp where you want the system to turn back on; I would suggest a differential of 5 or 10 degrees. For example, SV = 150°, AH1 = 150°, AL1 = 145°. Hope this helps.


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