An issue with adequate hot water could be related to the size of your electric water heater and not a maintenance problem. A hot tub that is not heating may be due to a tripped high limit switch on the heater which can be caused by clogged filters or blockage preventing water from flowing through the heater. Whats In A Water Heater Heater Repair Hot Water Heater Repair Water Heater Repair If your water heater is old—10 years or older—it’s possible that you have a broken heating element, thermostat, or gas valve. Why is my hot water not working but my heating is . Another possibility is that your tankless water heater is not big enough to supply enough hot water for your household. If this is the problem, then resetting the unit should fix it. The diverter valve is the part of your heating system that allows the boiler to switch between hot water and heating, depending on where the demand is highest. If the heater isn’t getting enough water, it would shut off and it wouldn’...