High Heat Fuse Replacement, Takagi T-KJR
Replacement of the High Heat Fuse
Replacement of High Heat Fuse to solve 4 wks of intermittent problems originally thought to be associated with the flame sensor, igniter, gas valve, gas line diameter etc. This particular fuse is more than likely the case of many of the videos and blog threads which I read which described a unit which was impossible to trouble shoot for many individuals. If you unit is not working or not working properly, do a continuity test on the high heat fuse as mentioned in this video to see if it faulty. You can also jumper the other side of the plug(going to high water heat fuse and printed circuit board, and make sure when you do this that the power is off. You can slide a small folded piece of aluminum foil down inside the plug so that it contacts to two pins. Then with your hands off of the jumped plug and clear of any metal (if it touches metal it will blow 250V fuse in system) turn the power on followed by turning a hot water tap on, and the system should fire up immediately. It it doesn’t check the pins in the plug to make sure the foil is actually touching both pins, and you can also check the fuse (250V). If the continuity check on the boiler side failed or is iffy, and the burner lights on the printed side of the plug, then your high heat fuse is toast and you need to do this repair. Once final fuse was inserted, the gas, water and other connections were verified and leak check on gas and water performed. Unit was test fired buy turning on hot water in house and there was a delay of about thirty 30 sec. before ignition due to the fact that gas had to refill all of the pipes from the shutoff to the igniter. Once this was done the system fired up immediately and has continued to work from then till now (about 6 months without a hitch). Good luck with your endeavor.