Digital thermostat connection

[Sailing Drummer]

My regular thermostat has died and I’m getting ready to install a digital one (Inkbird type from Amazon). I currently use one of these to control my spillover fan for the refrigerator temp. The output sends 12v.

My question is that I’m unsure of which way to hook it up. I have a Cool Blue system. I can see 3 options for hooking it up. 1) simply use this instead of my off/on switch; 2) hook this up with a relay to turn the unit off/on through the off/on switch; or 3) use the relay to turn a switch off/on that connects to the t-stat connection.

Currently I have an off/on switch connected to the t-stat connection, simply making continuity. It works fine except I have to manually turn it off/on and I only guess when to do that.

I’m leaning towards 3. But I’m wondering if the small mvolt that the relay sends will damage the control unit where the t-stat connection is.

Thoughts?

[Turtle Blues]

Hi Drummer,
Can't help but was following hoping to see answer to option 3. Have you tried contacting CB directly? They are usually very responsive.

[Bill O]

I'd go w/#3 also, but you could also talk to Rich Cruise RO and see what he thinks (he sells Cool Blue units) https://www.cruiserowaterandpower.com/


Let us know how he says you should hook it up.

[Sailing Drummer]

I spoke to Rich at Cool Blue. # 3 is the way to go!

[Paul L]

I use the Inkbird in place of the mechanical thermostat on on my old Coolblue. No relay required,

[Sailing Drummer]

Paul L

When I spoke to Rich I was under the assumption that the output was 12 volts because that is what is listed on the back of the t-stat for the output. Rich confirmed that the milivolts that a relay put out do not affect the Cool Blue.

However, after attaching the wires to the t-stat I checked for the voltage and found out that it actually makes continuity, not voltage - the label on the back is misleading. So I was able to go directly to the Cool Blue from the t-stat.