Update Low Hot Water Pressure Help

[Roback]

My PRV opened Monday during the night and disc a little water and closed. PRV almost new, 6 mos old. Since, very low hot pressure to faucets. Opened HWH drain, opened hot supply line to check for blockage. No luck yet. HWH 10 year old Bradford White. Any ideas. Help!

 

[Reach4]

1. Get one or two pressure gauges with a garden hose (GH) connector.
2. Put a pressure gauge on the hot water drain during your symptoms and record.
3. Put a pressure gauge on a cold line during symptoms. Your laundry tub or at least the connection that your washer uses would have a GH thread. Significant differences in pressure, during the same symptoms, between two spots will indicate a blockage. Your outdoor garden hose spigot would be another place you could check. If the cold water line's pressure was much higher than the WH pressure, measure the pressure of the hot at the laundry area.
4. When doing an update, it is better to add to the existing thread that has the background info.
I am not a plumber.

 

[Sponsor]

 

[Shane Wolcansek]

The age of the heater suggests it might have the type of heat trap nipple that had a ball inside that would sometimes get jammed, basically choking off the water flow in or out of the water heater. The PRV failure and resulting high pressure coupled with thermal expansion likely pushed one of the balls up and jammed it into place. Replacing those nipples should solve the issue. Checking the water pressure on the drain as suggested above is a great way to confirm it. If you have unions on the top of the heater it shouldn't be hard to replace these guys.