How trustworthy are the thermostat temps?

[Kaorte]

Have you tried going around the house with the temp gun and the thermometer? If they still give crazy readings it's either broken or the batteries are dead.

And like nixer said, temp guns don't take good readings off of reflective surfaces, so are you taking temps off the substrate or the bottom of the tub?

Bottom of the tub, maybe this is my issue.

I am going to try what you said nixer. I will be back momentarily with news.