I have a 1997 tiger river spa (Bengal model M). Brand new heater, new high limit, new thermostat. Circulation pump works fine in fact I took it out cleaned it and tested before putting back in....it's good. There are 2 lights 1 is red 1 is green according to Manuel and hot tub guys that's good too. Still no heat. I got this thing free and when I originally installed it it heated right up and was good for about 10 days and then stopped heating. That's when I replaced the heater and high limit and thermostat. Please help