Customer has no hot water: Over the past month, there has been multiple repairs on her system, including aquastat replacement, Circulator pump and mixing valve replacement, And repairing broken heating lines: At arrival, I found the Tako zoning panel receiving a call from the domestic hot water tank for hot water. Zone six LED is illuminated and the circulator pump is on and running. The boiler is off. Check voltage to the aquastat on the boiler and found that the end switch was not closed Start checking the takeover zone panel - while removing the zone panel cover the end, switch closes on the boiler fires. The customer is there to see. Every time the Taco zoning panel Is touch there is an intermittent issue at the end switch opens or close. Bad zoning panel Was able to get the boiler to stay on and running in the end switch closed. Monitor boiler operations. Confirm that the boiler is shutting down a temperature and not overshooting. Confirm that the circulator pump is on and running