Engine heat loop from AquaHot

[davidbrady]

Hi Jonathon,

Below I attached the AHE-100-02S Service manual. Page 27 has troubleshooting steps for the engine loop heating function. As you've already discovered fuse 'A' is the fuse for the engine loop pump. The manual goes on to explain the procedure to replace the pump brushes, they often go bad. I don't think the DD Series-60 thermostats come into play. When the DD t-stats are closed the DD water pump circulates coolant thru the head which is where the AH taps in, so there is a fluid path even with the t-stats closed. But, my New Year resolution is to kick my caffeine habit so bear with what may be my fuzzy logic! LOL!