Quote:
Originally Posted by Daox
What are the benefits of mechanically circulating the coolant?
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In the traditional thermosyphoning system the flow of coolant is extremely slow. Because of this, a lot of heat is lost before the coolant even makes it through the lines and into the engine. Once in the engine the coolant loses its heat in the inlet side of the engine and is cold again by the time it comes out the other end, leading to an engine that's (relatively) hot-to-cold from one side to the other.
Because the rate of colant flow is so minimal, the high heat element typically boils the coolant inside the heater, leading to deposits forming on the element and eventual element failure. Also, the temperature of the coolant leaving the heater is so high that hose failure is common where it attaches to the heater.
A pump circulated system runs at much lower peak coolant temperatures, heats the entire engine much more consistently, and typically requires less power as well as heating in less time all due to less thermal losses at the heater outlet. The drawbacks are added system cost and complexity.
The industrial pump circulated heaters feature an optional thermostat on the coolant intake on the pump that cycles the heater to keep the engine at a pre-set temperature, another energy saving feature. This is a feature I would like to incorporate as well, but I need to jump the pump hurdle first.
The dishwasher drain pump I have will definintely pump water, but I have my doubts as to whether it will reliably survive the underhood environment as well as not become a source of a leak operating in a cooling system with a 20 psi rad cap.
High coolant temps shouldn't be an issue as the Zerostart heater has a one-way check valve integrated into the inlet to keep coolant from flowing back through it while the engine is running. As such, the highest coolant temps it should see will be the return temp while the heater is functioning.