In using an outdoor wood stove, one thing that many will overlook is the need for proper water treatments. Your water needs two kinds of treatments, one for the pH levels to help prevent corrosion, and a second for helping to keep the water from freezing or losing its heat too rapidly, causing you to use more wood in between burning cycles.
Water pH Treatments
The need to treat water pH is a simple and basic one. It is also frequently required to not invalidate your warranty.
There are many test kits and solutions for sale, making this part of outdoor wood stove care fairly easy. Simply test, then add pH treatment solution as needed.
You need to keep an eye on pH mainly to prevent the unit's heat jacket or other connected metal parts (like your heat exchanger) from rusting out. Not doing so, will, as noted, frequently invalidate your warranty.
Heat Transfer Solution Treatments
A lot of people just use antifreeze for this, because it is cheap and readily available. We do not recommend antifreeze because it is toxic, breaks down rapidly, and can have a negative impact on the pH of the water in your unit, calling for more pH treatments than you would need otherwise.
Many manufacturers are moving to recommending non-glycol based solutions for heat transfer and freezing prevention. One that comes highly recommended by Michigan manufacturers is GreenTemp® HT. This solution is a bio-degradable, lubricating, natural and long lasting alternative to antifreeze that is also non-toxic. We have so far heard nothing bad about it. Due to the fact that it lasts a minimum of 2-3 years before it starts to break down, you also get savings over time due to how long it lasts.