This 4kW (4000 watt) Watkins No Fault Heater is the factory replacement for the Hot Spring Envoy & Vista beginning in 2004, Grandee GG model beginning in 2005 and Aria beginning in 2006. It’s also the replacement for the 2005-2010 Tiger River Caspian and all Limelight spa models.
Note: This heater has a built-in pressure switch that plugs into the P34 port on the IQ 2020 motherboard. The advantage of this heater over the 73791 PDR Heater is that the IQ 2020 spa control system will alert you that this heater has shut down by displaying a blinking green Ready light and a blinking red Power light on the control panel. The 73791 PDR Heater will just trip off internally with no alert other than the spa water cooling. This heater and the 73791 have never been factory installed on a 120volt Hot Spring or Tiger River spa.
Note #2: It is highly recommended to purchase new thermistors, 79006 and 79005, with this heater. The inlet thermistor port on these style heaters may require a wrench to thread in the thermistor. If your existing thermistors plug in to the OUTSIDE of your control box, please use item 78970 and 78969 as replacement thermistors. This heater comes with new thermistor o-rings.
Warning: This heater is not backward compatible meaning that it cannot replace a non-pressure switch heater or there will be no protection if the heater “Dry Fires”.