Winter heater suggestion for Virginia

JoyfulNoise said:

The ETI heater design is simply the same heating design as a condensing water heater - the hot exhaust combustion gas is used to preheat the water load before it enters the heat exchanger. This heat transfer typically causes the exhaust gas to fall below the condensation temperature of the gas mixture resulting in a build up of very acidic condensate liquid. This condensation gets worse as air temperatures drop. The exchanger is made out of titanium but even titanium is not indestructible and so there are typically very specific air temp and water temp conditions that need to be adhered to or else the condensate will rot everything else out. Normally one needs to install a condensate neutralizing filter on the output of the drip pan that captures the condensate and moves it away from the heater body. But if acidic pool water is present, then the internals of the heater will still be subject to corrosion.

Efficiency and quality really don’t matter if the source of the problem (acidic water in the heat exchanger) isn’t addressed. The ETI is >90% efficient. The Regular MT is ~ 85% efficient and the HD that has the cupronickel exchanger is the least efficient (< 80%). Only Pentair can give you their estimate of reasonable lifetimes based on usage pattern. If your plan is to fire them up year round, then the wear and tear is pretty high and someone should be servicing them regularly to keep them running. Just like an automobile, if you only wait to change the oil and tune up the engine when the check engine light comes on, then the damage done is far worse than a simple oil change will remedy. None of the heaters will last if the water going into them has acidity issues.

Click to expand...