For those that have the flat plate and the hydronic Espar. If you use the heater after the engine is cold you will notice that it takes sometime to get any real hot water out of the flate plate. Reason is that you are heating 7 gallon of water in the engine and the engine is a big giant heat sink also the colder it gets the longer it takes. We have a way for you to get almost instant heat now. It involves installing a thermostat and check valve. It will maintain the loop at 160*. When it gets to 160* it will then allow the water in the motor to be heated. Not sure how much water the flate plate loop would hold but I do know that you will have all the hot water you can use in 5 minutes or less.
Greg
Greg