Post edited 9:09 am – November 26, 2011 by q240z

Hi.

I've got a 2004 Mermaid 16kbtu self-contained reverse cycle unit in a 1967 Chris Craft Connie that suddenly won't stop cranking out the heat. Even with the Mermaid electronic thermostat/controller set to 65*, the unit stays on all the way up to 80*. It will only shut off if I move the selector switch from heat to off. Resetting the thermostat/controller with the "reset" button had no effect. Also, previously I could turn the switch from off to either heat or cool and it would take a few seconds (and sometimes longer) before the unit would kick on even if the temperature was at a point where the controller should have been calling for heat or cooling. It always kicked on eventually though. Now, as soon as I move it to heat it kicks on immediately.

I just tried it on cool and the same thing happened–even though the controller should not be calling for cool, it kicked on immediately.

Thanks in advance for any suggestions you might have for me.

Cheers,

Q

Hi Steve!

The t-stat is a Mermaid branded "CTC/Hunter" model 43103 digital programmable thermostat. From Mermaid's website it seems they used these for many years but stopped in the early oughts. I must have gotten the last one going out the door. lol

The fan-only feature turns on and off when the fan switch is moved from On to Auto, as it should. The complete unit (fan and compressor) turns on and runs normally (ie kicks out heat or chilled air) when I turn it to Heat or Cool, it just doesn't shut down when it reaches the set temp. It does shut off completely when I switch it from Heat or Cool to Off. The only thing that's not happening as it should is that it doesn't shut off when it reaches the set temp.

Excellent! Do you sell replacements for these, or is any programmable 4-wire thermostat acceptable?

That is a very slick looking thermostat. For this Connie, which is up for sale, it's a lot more bang than I need. But I'm refitting another boat and will keep this in mind. I really like the idea of a dehumidifier function.