I have done both the thermocouple sensor and the themal fuse-the former cost (parts) $18, the latter $16 at a plumbing supply house. Each took about 30 minutes to replace and I did it myself. Our local service plumber quoted $75 + parts-most of which was the show-up fee-and $50/hour after the first hour.
Using the squatty potty for elimination will reduce straining and decreases the pressure in the veins. The reduction of straining will help to heal and prevent hemorrhoids. It will also reduce the risk of bowel herniation and other damage to the lower digestive tract. The Squatty Potty is attractive and will discretely tuck under your toilet bowl when not in use.
Putting off bowel movements can worsen constipation, which then aggravates hemorrhoids. Try elevation. Elevating your feet a bit with a step stool as you sit on the toilet changes the position of the rectum in a way that may allow for easier passage of stools.