Tankless Water Heater Fan Starts w/COLD Water
We just had a Takagi T-M32 tankless water heater installed in a down to the studs remodel of our house. The house is two stories, 2800 square feet, with 2 full bathrooms (only one tub though) and a half bath, 2 kitchen sinks and 2 laundry rooms (the second laundry room is for an in-law area). Our plumber recommended the T-M32 which is a commercial level heater because of the possibility that both families will be using a fair amount of hot water at the same time. The problem is that the fan on the tankless water heater fires up when some of the faucets in the house, but not all of them, call for COLD water. It also happens when a toilet is flushed. The gas/ignitor of the heater doesn't fire up (just the fan), in preparation for the next step which would be the gas firing up to heat the water. I don't think our plumber knows what he is doing but he thinks it is an issue with water pressure (?). Does anyone have any ideas why this might be happening. The fan is VERY loud as the tankless heater is installed in a bedroom closet, so it will be very disturbing to the person sleeping in that bedroom if the fan kicks on every time a toilet is flushed or someone turns on the cold water. I understand this will happen when the hot water is turned on, but this does not seem right to me that the fan should kick on when cold water is being requested from a plumbing fixture.