TERRY LOVE FORUM;
I had the same Takagi problem and with this forums' help, I fixed it quickly.
Takagi has a fuse wire wrapped around the back and sides of the heat exhanger
and it is called the HEAT ECHANGER OVERHEAT FUSE. It is connected with blue
wires and a cheap white plastic connector to the HIGH-LIMIT SWITCH in the
extreme upper left of my TK3 unit. Mine had BURN MARKS ON THE CONNECTOR
and when I "cheated" it out with a paperclip, I got hot water.
So, why did it happen? My unit lives outdoors on the porch, and our summers
are hot, about 105 or so on the porch. This may have caused a false overheat
signal, but the connector was burned brown where the wires went into it.
I will repair the bad plug, and maybe open the air vent above this area to drop
the internal heat in the housing. I will let you know if it helps. Tiny automotive
probes and tools from the tool truck help with the repairs.