Originally Posted by WesK
Has it ever worked in the heat mode since you replaced the thermostat?
Yes....Mermaid uses a simple 4 wire (home style) thermostat. Works perfectly on the cool side. Temps trigger it on and blower works perfectly. I did replace the blower this past winter, but it was an identical unit to the original so that should not be the issue...
I'll check thermostat connections first and look at the valve..