I've been tweaking the buffer tank's upper and lower temperature settings to try to get the most heat I can into the tank, and allow the most use of the tank. The BioWin's max internal and external setpoints are 176, but that can be overshot by some undetermined amount as the unit modulates down.
The tank controller I put together is latching, (thanks again, ewdudley), and the sensors are at the top and a little above the return opening at the bottom. With settings of 150/168 (top/bottom), I was able to eventually get a final reading of 181/174, with a boiler temp if 186. This was after the heat call from the tank was stopped, the circ pump run on 'purge' for 10 minutes, and the boiler shut down and in stand by. There was no call for heat from the zones, which is a big factor.
For the next cycle, I changed the settings to 145/170. Even if the controller doesn't initially see 170 before the boiler shuts down, it will after the boiler pump runs for a while in shutdown and then the pump will shut down after that 10 minutes I mentioned before. The issue could be if there are heat loads during that time with the boiler shutting down. Then, the controller might not see that temperature, and the pump would continue running until the boiler starts again on its own. We'll see how that works.
The fact that there's virtually no heat load is a factor now.
The boiler is protected by a thermomix valve and the boiler pump won't run unless its temp is above 130.
Any ideas/suggestions? I don't want to fly too close to the sun.
The tank controller I put together is latching, (thanks again, ewdudley), and the sensors are at the top and a little above the return opening at the bottom. With settings of 150/168 (top/bottom), I was able to eventually get a final reading of 181/174, with a boiler temp if 186. This was after the heat call from the tank was stopped, the circ pump run on 'purge' for 10 minutes, and the boiler shut down and in stand by. There was no call for heat from the zones, which is a big factor.
For the next cycle, I changed the settings to 145/170. Even if the controller doesn't initially see 170 before the boiler shuts down, it will after the boiler pump runs for a while in shutdown and then the pump will shut down after that 10 minutes I mentioned before. The issue could be if there are heat loads during that time with the boiler shutting down. Then, the controller might not see that temperature, and the pump would continue running until the boiler starts again on its own. We'll see how that works.
The fact that there's virtually no heat load is a factor now.
The boiler is protected by a thermomix valve and the boiler pump won't run unless its temp is above 130.
Any ideas/suggestions? I don't want to fly too close to the sun.