Ranco Digital Temperature Controller

geodehunter · Dec 15, 2018

This may be a dumb question but I was wondering if you could possibly wire a Ranco controller to run 2 heaters? Lets say to set the Ranko at 77 degrees and set one of the heaters at 78 and the other at 79. The reason I ask is if one heater fails the other one would now go into operation. I don't know if anybody has tried this so I thought I would ask. Thanks!!!

CC13 · Dec 15, 2018

geodehunter said:
This may be a dumb question but I was wondering if you could possibly wire a Ranco controller to run 2 heaters? Lets say to set the Ranko at 77 degrees and set one of the heaters at 78 and the other at 79. The reason I ask is if one heater fails the other one would now go into operation. I don't know if anybody has tried this so I thought I would ask. Thanks!!!

Following along.

Muttley000 · Dec 15, 2018

The Ranco can handle the amperage of two heaters, but the ones I've seen have only one output, so it could not differentiate which heater it ran if that is your plan. The way you describe it I would expect both to run every time the Ranco called for heat. That being said in my system the Ranco keeps my temp about .3 degrees of each side of the setting so I think you would be happy, and setting it up as you describe gives you an important level of redundancy should one of them stick on, which is a common and potentially catastrophic event.

geodehunter · Dec 15, 2018

Muttley000 said:
The Ranco can handle the amperage of two heaters, but the ones I've seen have only one output, so it could not differentiate which heater it ran if that is your plan. The way you describe it I would expect both to run every time the Ranco called for heat. That being said in my system the Ranco keeps my temp about .3 degrees of each side of the setting so I think you would be happy, and setting it up as you describe gives you an important level of redundancy should one of them stick on, which is a common and potentially catastrophic event.

Thanks for your reply!!! I never even gave a thought to one of the heaters sticking on. That's definitely a very valid point. I think I would be better off just getting 2 Ranco's then. I would like to have a back up just in case anything would happen.

ca1ore · Dec 15, 2018

Not that a typical thermostat controlled stick heater cannot get stuck on, its far more likely that it fails off. Just figure out how much wattage you need for your system, divide that number by two and buy three heaters of that value. That way, a single failed heater can neither cook nor ‘freeze’ your tank. If you buy thermostat heaters, set them a few degrees higher than the Ranco. Ranco has a setback feature, by the way, which gives you control over the thermostat range. Set to 1, it iterates 0.1 F around the setpoint; set to 2 it iterates 1.1 F; 3 = 2.1 F, etc. Designed mostly to prevent short cycling in chill modes, but you could use it for heating as well.