John Carrillo (
http://heatmyrv.com/)serviced our HydroHot when we were at the Ale Trail rally in Bend. We had been having trouble with inconsistent water temperature for a couple years. I explained that a couple other AquaHot techs had looked at the system and had not been successful. He offered to do a thorough trouble shooting procedure, top to bottom.
His first step was to get the water to antifreeze ratio back to specification. He used a refractometer similar to this one:
http://www.amazon.com/Antifreeze-Refractometer-Rha-200atc-Temperature-Compensation/dp/B0095DHLSW/ref=pd_sim_sbs_indust_4?ie=UTF8&refRID=1H85837JVZ7TBGZ1ECPR.
John determined that with nearly ten years of use, enough water had evaporated that my mix was out of balance and explained it was normal for more water to evaporate than ethylene glycol. He siphoned out about a gallon of coolant and replaced it with water.
Throughout his testing he measured the temperature of water output by running the outside shower on the pavement and aiming an IR thermometer at it. He checked the operation of the various thermostats and valves. It remained inconsistant. Towards the end, he explained that the last item on the list was the stir pump that can appear to be working but can be running at partial performance. The only way to determine the performance of the stir pump was to replace it, which solved the problem. John explained that the only way to trouble shoot the stir pump was to verify that every other piece of the puzzle was correctly operating leaving the stir pump as the last possible weakness.
We finally got consistent hot water.
