Smart Low-Flow Heater for Sundance/Jacuzzi 6500-310 5.5kW

The original (20-year old!) heater was still working until I installed a temp sensor incorrectly and accidentally dry-fired the heater. So I was very pleased to find this unit with a Hi-Limit Sensor included for the price. The one thing they don't say in the instructions is that the new high-limit sensor isn't supposed to seat all the way in as the old one does. But SpaDepot's support was great. They confirmed that it just needed to be caulked with some silicone to hold it in place. (See pics: old heater/sensor on the left, new units on the right.)
And, many thanks to John Reihing, who described in his review on this site how to keep from dry-firing it. Because of him, I was able to self-install with confidence.

Perfect replacement. Easily installed. No more water leaks. Spa is up and running!

Exact replacement. Be careful - if the grounding rod moves it may leak, but some silicone sealer will fix it. I had the first heater replacement just before the 5 year warranty and the it barely lasted 2 years before leaking around the bottom element seal. I hope this one lasts longer. But installation was easy.

Installed it last week and appears to be working just find - solved my FLO problem as existing heater had so much calcium on it that calcium chips were flaking off and obstructing the heater flow.

it is just like the one l took out, easy to install and works great.