Control Tstat replacement; HS Grandee 95

[Keith A.]

OHi there! Need some help. Removed Tstat from our 1995 Grandee G, with part label #31080. Found replacement Tstat on eBay for TigerRiver or HS spas, with part label #75077. Instruction sheet says plug & chug for TRiver, but if HS, use a jumper wire provided to ensure proper connection to AC vs DC side of rectifier. Big hint is whether there are orange wires or black wires. The two spade-clipped wires I pulled to remove old Tstat are one black and one light blue. There are two stickers on new Tstat, one reads 2.0 VA @ 110VDC, or 3.0 VA @ 28VDC. My instinct tells me to power up breakers and check for voltage across the black/blue spades for AC or DC. Further, instructions say if no orange wires, skip mult steps and go to 12: attach the black jumper provided between Tstat and heater relay coil rectifier. Sounds easy enuf, but I wanna be more confident about this change-out. Any experience with this procedure, and any advice? Thanks!

[Keith A.]

Add’l info: we keep temp at 104 in winter. One evening, temp dropped to 99. Rotated the analog Tstat up a few degrees and wham, temp soared to 108. Attempts to nudge back down brought 94. The tell tale clicks when you rotate the Tstat dial, passing over/under the temp threshold, were no longer audible. That’s why I thought it would be a bad Tstat. Perhaps there is another problem? I just powered up both breakers and read no voltage across the black and blue spades that were attached to old Tstat. Was hoping for an easy fix for the old girl.

[Keith A.]

Add’l info #2: the mod directions call for ALL HSpring models 1990-93, but ours is a model year 1994, and no orange wires anywhere. I have re-installed the 75077 Tstat and am ready to power up the spa and see what happens. Anyone have any reservations about this?