What are the valves under my tankless water heater?
The valves under a tankless water heater are isolation valves: one on the cold water coming in, one on the hot going out. Each has a small side port. Closing them and hooking a pump to those ports is how a tankless gets flushed with descaler once a year.
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From one of our jobs
A gloved hand on the isolation valves
Right now: Find the colored handle valves under your tankless and leave them open unless it’s being flushed.
A tankless heats water as it passes through a small heat exchanger, and scale builds up in there faster than in a tank. When it does, you get error codes, water that runs hot then cold, and less hot water than it used to make.
The yellow handles shut the water off to the unit without shutting off the house. The side ports let us run descaler through the heat exchanger in a loop, then flush it clean. Without these valves, the service takes much longer.
Quick answers
What people ask about tankless water heater valves
What are the two valves under a tankless water heater?
Isolation valves, one cold and one hot. They shut the water off to the heater and have service ports for flushing it.
How often should a tankless water heater be flushed?
Once a year in most Northern Virginia homes. Harder water or a softener that isn’t working can mean more often.
Can I flush my tankless water heater myself?
If it has these valves and you have a pump, a bucket and descaler, yes. Shut the power or gas off first, and follow the manual for your model.
What happens if you never descale a tankless?
Scale chokes the heat exchanger. You get error codes, temperature swings and eventually a heat exchanger that has to be replaced.
Who do I call to service a tankless water heater in Northern Virginia?
Call SwiftPro at (703) 997-9757. Our plumbers descale, repair and replace tankless water heaters across Northern Virginia.
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SwiftPro Heating, Cooling & Plumbing
4230 Lafayette Center Dr N, Chantilly, VA 20151
44679 Endicott Dr, Suite 211, Ashburn, VA 20147
SwiftPro Plumber & Water Heaters
4200 Lafayette Center Dr, Suite N, Chantilly, VA 20151
Virginia Class A contractor license #2705192276