Low hot water pressure issues can stem from the source of hot water or localized at the faucet. If certain fixtures exhibit low hot water pressure while other fixtures don’t appear to have the same problem, the issue is most likely at those fixtures. Most commonly scale build up in the aerator or the shower head.
You may use vinegar or a calcium lime rust remover to clean up scale deposits and restore flow.
If all hot water fixtures in the house appear to have low hot water pressure, more than likely the restriction is at the source of hot water. Our tankless water heaters have an inlet screen filter to catch debris and prevent it from getting into the unit. Over time depending on water quality and other factors build up may accumulate in the filter and it needs to be cleaned. In most cases cleaning the inlet filter is something the homeowner can do themselves. The following video will give a basic idea of the process.
If you have had low hot water pressure from the day your tankless was installed, it could be that the incorrect size tankless unit was installed for your application. Tankless water heaters are installed based upon the peak demand2 in an application. Also you will get less hot water flow in the winter than in the summer, due to the reduced inlet water temperature. When sizing a tankless water heater use the worst case temperature rise1 for your region along with peak demand.
A local Noritz service representative can be located on our Contractor Locator.
Temperature Rise1
The difference between the set temperature of the tankless heater and the ground water temperature (e.g. 120 Fahrenheit setting – 60 Fahrenheit ground water = 60 degree Fahrenheit rise.)
peak demand2
the largest gallon per minute flow rate experienced by a plumbing system during normal operation
Applicable Models
- Models: ALL MODELS