Issue: This morning, my Solo 40 boiler was at 170 degrees, the circulator pump was on, the water between the circulator and first radiator was 85 degrees (heating loop temperature) and the house is 56, when it should be 62 by the thermostat. My current work around: I shut the valve to the tempering valve off for 5 seconds or so, open it up to full for 5 seconds or so and put it back at the 45 degree position. I then use a valve just after the check valve which comes from the boiler and feeds the 2 circulating pump and turn it off, then turn it back on full. What happens: The change is not instant but the heating loop temp seems to go up slowly to 90 degrees in the 1st 5 minutes, then faster until it gets to 120 or so within 10 minutes. I am not sure of the environmental conditions when this happens. I have a programable thermostat where I tell it to be 62 from 10 PM to 4 AM, then to heat up to 68 degrees. Seems like I have done the "trick" 4 times in the last 2 weeks. Last night it was 2 degrees outside. Other times it seems to be 30 degrees during the day when this happens. However, 2 hours to temper the heating loop water is too long, expecially when the "trick" has an "immediate" effect. My guess: the Termovar valve is "stuck" and the pressue changes impact it just enough. I guess it could be a partially open check valve between the boiler and the circulators, where the pressure changes frees it up and then the Termovar starts to increase the volume of tempered water to boiler. Any ideas?