What Size?
Therma-coil is manufactured in two sizes depending on the stove size and the amount of hot water needed. Smaller stoves tend to have a higher firebox temperature and generally are better suited to the single U-shaped model. Larger fireboxes need more surface area and generally work best with the W-shaped model. Climates that use woodstoves all the time throughout long winters will see more hot water produceded in a Therma-coil than milder areas with intermittent stove use and should be sized accordingly. Measure the inside of the stove to determine which coil will fit, remembering that the Therma-coil is 16" long inside the stove with an additional 5" threaded nipple length that exit through the stove wall (overall length is 21").
Placement
Therma-coil placement inside the stove also determines sizing. The coil can be placed inside the firebox vertically along the side or the rear of the stove exiting out the rear or side stove wall. However, this usually takes up firebox space, can get covered with ashes that are pushed up and reduce performance, and is more prone to being hit with logs. When possible, it is recommended the coil be placed high inside the stove, horizontally under the griddle and out of the way of logs. Therma-coil will capture some of the heat escaping up the flue in this location. Increasing the amount of hot-water at a later date can be accomplished by adding another Therma-coil and plumbing it in series with the first one. In most cases, the heat needed for domestic water heating will not affect the burn characteristics of the stove.
