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Author:
houseplbg (TN)
Expansion tanks are needed on water heaters when a house has a closed system.
Can someone tell me how to identify a closed water system on a house? If a pressure regulator is installed on the main line entering a house does that mean that 100% of the time the house has a closed system?
Just trying to figure out what to look for to tell me it is closed
Thanks
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Author:
hj (AZ)
If the PRV has an internal relief valve, then it is not a closed system. If the system has a check valve on the incoming line, then it is a closed system.
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Author:
houseplbg (TN)
is there something on the PRV valve that tells me it has an internal relief valve?
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Author:
hj (AZ)
No. You have to look up the make and model number.
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Author:
RRWA (WA)
Please post the brand and model number of the PRV(Pressure Reducing Valve). Using that, you can look up the spec sheet.
To answer your original question, here are some options:
1. Look for a check valve installed near your water meter or in the water meter itself. This would indicate a closed system.
2. Call your water utility and ask them.
3. Do you have an expansion tank installed? This is an indicator of a closed system.
4. Test your water pressure. An inexpensive gauge can be purchased at Home Depot in the irrigation/sprinkler aisle . It screws on to your outdoor hose bib or water heater drain valve. Further details below.
If you can do some pressure testing, you may be able to figure this out yourself. Find the following measurements:
1. Water pressure from the city water main, before the PRV. This is reading #1.
2. Water pressure on the house side of the PRV with the system in normal state. First, open a cold faucet for 15 seconds to relieve any excess pressure. Turn it off. Make sure the system is at rest, with no water being used. Measure the pressure. This is reading #2.
3. Fill up your bath tub with hot water. Drain it. Wait 30 minutes and do not use ANY water(cold or hot) during this time. Now measure the water pressure on the house side of the PRV. This is reading #3.
If reading #3 exceeds reading #1, you have a closed system.
Note: if your city water pressure is too high(say, > 100), this test may not provide useful results.
Please post the results of your pressure tests.
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