Inkbird temp controller

[ericbreen]

Hello has anyone had a problem with the ltc-308 digital temp controller failing? My unit is only about a year old, but it is having a serious problem. I the 308 in my fermentation chamber. I live in a cold climate so i only have a large bulb light connected to the heat side and noting on the cool side. in the past the light turns on to heat then shuts off to cool. This has worked fine up until last week. I hear d the 308 beeping and I checked the chamber. The digital display read like 80 degrees, yet my light was still on-heating even more. I unplugged the unit and left it that way for an hour or so. I then plugged it back in only to have it do the same thing. Any ideas?

 

[augiedoggy]

How many watts is the bulb? What was the temp set to? This might sound silly but you might want to double check that you have the bulb plugged into the heating and not cooling outlet.

Sounds like the contacts fused shut.. This could but shouldnt really happen unless the controller was setup with no time delays and was turning the relay on and off fairly quickly or you have some sort of large electrical load that was beyond what the 10amp relay can reliably handle.. mechanical relays are like a light switch.. they are good for so many cycles and eventually wear out. But they should last a lot longer than a year in normal use.

 

[MaryB]

Every time a relay closes and opens it creates an arc that eats a bit of the contact. Eventually they either weld shut or no longer conduct. I use STC-1000 controllers with outboard solid state relays to take the load off the controller and put it on an easy to replace piece. Plus the solid state relay will last 100 times longer than the mechanical relays in the controller. Just got in an ITC 1000 PID controller to build the new controller for the bigger ferm chamber.

 

[BullGator]

MaryB, can you share your wiring diagram? I'm trying to do the same thing with an LTC-1000 temp controller and I'm not sure how to wire it. What kind of SSR did you get? You are using the PID controller right? Why did you go with that?

 

[augiedoggy]

Every time a relay closes and opens it creates an arc that eats a bit of the contact. Eventually they either weld shut or no longer conduct. I use STC-1000 controllers with outboard solid state relays to take the load off the controller and put it on an easy to replace piece. Plus the solid state relay will last 100 times longer than the mechanical relays in the controller. Just got in an ITC 1000 PID controller to build the new controller for the bigger ferm chamber.

To ad to this when a mechanical relay opens and closes quickly the contacts can actually burn up on the surface or weld shut. in an application like controlling a fridge or fermenter temp control an stc1000 SHOULD work fine because there should be adequate time delay between switching. Ive been using one myself on one of my kegerators for at least 4 years now with no issues and I used them to control my glycol system and heater strips for well over a year without an issue. its really rapid switching or overloading the contacts amp ratings that kills them quick. Hysterisis temp controllers are still ideal for this vs pids though unless you set the pid up to act as a hysterisis controller and add time delays.