Turn off pump when tanks are hotter than boiler

[tuolumne]

First issue: I am now heating with my buffer plumbed in. My EKO controller has a maximum pump setting of 160 degrees. This severly limits my ability to leave the boiler full of wood on our way out the door...once the fire is out, the pump will keep running until temperatures drop below 160...this is wasteful of electricity and heat. My pattern so far is to charge during the daytime so I can manually shut down the boiler when the load is gone. This also has some problems; often the bed of coals left can run the water in the boiler up to 212 once the pump is off. Ideally, I would be able to set the circulator at anything up to 195. That way I could walk away knowing things won't overheat and I won't be wasting kilowatts when the fire goes out. Any ideas?

Second question: How much insulation has been used by you all, and how well does it work. Right now I have the tanks covered in 2" of high denisty spray foam insulation (about R14) and the basement is still plenty hot. I plan to drape R-19 batts over the top and sides before closing in with plywood. Is this enough?

Edit: I just found a current discussion on the first issue, so please ignore my sill repeat. I'll follow that thread!

 

[sdrobertson]

First issue: I am now heating with my buffer plumbed in. My EKO controller has a maximum pump setting of 160 degrees. This severly limits my ability to leave the boiler full of wood on our way out the door...once the fire is out, the pump will keep running until temperatures drop below 160...this is wasteful of electricity and heat. My pattern so far is to charge during the daytime so I can manually shut down the boiler when the load is gone. This also has some problems; often the bed of coals left can run the water in the boiler up to 212 once the pump is off. Ideally, I would be able to set the circulator at anything up to 195. That way I could walk away knowing things won't overheat and I won't be wasting kilowatts when the fire goes out. Any ideas?

Second question: How much insulation has been used by you all, and how well does it work. Right now I have the tanks covered in 2" of high denisty spray foam insulation (about R14) and the basement is still plenty hot. I plan to drape R-19 batts over the top and sides before closing in with plywood. Is this enough?

First issue: I'm using a 2 way controlled valve with a bypass loop to the boiler feed to control when my water goes to the storage. It has to be over 183 degrees to go past the valve and if not, then the water loops back to the feed. I'm still working on hooking up something to kill the boiler when my bottom storage water gets to 175 so that's still a work in progress.

Second question: I searched and searched and finally came up with blown in cellulose as the best behind spray-foam. I would box it and then blown in 4 inches (more the better) on the sides, and double it for the top. Seems like the value of dense packed is around r10 per inch but its been awhile since I looked this up. I have 14 inches on the sides and 2 to 3 feet on top of my tanks and then 4 more feet of Styrofoam balls in a uninsulated pole barn and I have no frost melt on the roof from the tanks.

 

[WoodNotOil]

If I understand what you are trying to do, a differential controller like the ones Tekmar makes might work in this situation. The 156 would probably work unless it is a variable speed pump. They have two sensors (one on boiler, the other on the tank) and turn the pump on and off by comparing the two readings. It allows you to set a differential of how much hotter the boiler needs to be than storage to turn on.