Originally Posted By: mthomas2
This post was automatically imported from our archived forum.
but it uses more than twice the gas as the furnace(!)
[ Image: http://www.nachi.org/bbsystem/usrimages/T/TakagiPlate.jpg
High input BTUs also mean gas line line sizing is another thing to watch, most units require ?? ALL THE WAY to the unit - when I talked to the Takagi rep on another matter he told me around 80% of the problems he sees on new and retrofit installations are the results of undersized gas supply. Sizing this is beyond most SOPs, but if you see a 1/2" pipe serving one such a unit, try to check the installation instructions.
Some other units are sealed (see below), drawing their air from the exterior, on both types of units look for a back draft preventer (directly above both the units shown here and marked with an arrow below) in freezing climates, units can and freeze and burst otherwise.
Most require SS vent pipe sealed with high-temp (red) sealant per manufacture?s instructions (arrow at left):
[ Image: http://www.nachi.org/bbsystem/usrimages/T/TakagiSealed.jpg
Though not required, drain valves are a sign that the plumber was familiar with such units:
[ Image: http://www.nachi.org/bbsystem/usrimages/T/TakagiDrain.jpg
On some of the Takagis, if an output temp other than the factory pre-set (around 125F) is desired, an accessory wired remote control is required.
[ Image: http://shop.com.edgesuite.net/ccimg.catalogcity.com/220000/228700/228774/products/22541432.jpg