Woodmaster 4400 low water temp coming from stove ETC says 170 degrees, temp at both outlets is 145 degrees. Checked the probe with outside temp, within 2 degreesof ETC. Replaced ETC with know good unit from working stove. Checked water temp at top vent with deep fryer thermometer. Was 170 degrees. pumps are located 25 feet from stove but lower them stove by 1 foot. What am I missing?