View Full Version : Sudden loss of hot water (only) flow
Neda Roberts
Oct 18, 2014, 08:51 AM
A few days ago a cold water pipe burst. I'm in a mobile home & have no indoor shut-off valves so the water was turned off to the entire house at the outside main. I temporarily fixed the pipe and turned the water back on. No problems. Yesterday, I turned the water off again to permanently fix the pipe. Now that the water is back on, my cold water flow is fine, but the hot water comes on normally, then gradually loses pressure/flow after a few seconds. It's probably at about a 1/4 of the normal flow. It still gets hot, I've just got no flow. This is a relatively new water heater (less than 2 years) with all new fixtures and pipes running to it so I'd be surprised if sediment was an issue. Thoughts? Suggestions? Any help would be greatly appreciated!
hkstroud
Oct 18, 2014, 09:13 AM
but the hot water comes on normally, then gradually loses pressure/flow after a few seconds.
That, of course means that there is restriction, a partial blockage, in the hot water line somewhere.
If the restricted flow is at one faucet, such as the kitchen, then the restriction could be at the aerator or the stop valve for that faucet. If the restricted flow is at more than one faucet then the restriction will be between the point where the water line comes off the main and the input valve to the water heater. If the water heater has heat trap nipples it could also be one of the heat trap nipples but that it unlikely since the water heater is only two years old.
Restrictions or blockages only occur at valves.
What type of pipe was it that burst and how did you repair it.
Neda Roberts
Oct 18, 2014, 09:26 AM
The flow gradually slows at all faucets. The pipe that was repaired was the line that goes from the main into the house, into the toilet tank. I simply replaced the damaged section of pipe.
That, of course means that there is restriction, a partial blockage, in the hot water line somewhere.
If the restricted flow is at one faucet, such as the kitchen, then the restriction could be at the aerator or the stop valve for that faucet. If the restricted flow is at more than one faucet then the restriction will be between the point where the water line comes off the main and the input valve to the water heater. If the water heater has heat trap nipples it could also be one of the heat trap nipples but that it unlikely since the water heater is only two years old.
Restrictions or blockages only occur at valves.
What type of pipe was it that burst and how did you repair it.
The flow gradually slows at all faucets. The pipe that was repaired was the line that goes from the main into the house, into the toilet tank. I simply replaced the damaged section of pipe.
hkstroud
Oct 18, 2014, 10:50 AM
Was that copper pipe which required soldering?
Neda Roberts
Oct 18, 2014, 01:30 PM
Was that copper pipe which required soldering?
No. Just CPVC & a new coupling. It's all CPVC.
massplumber2008
Oct 18, 2014, 02:22 PM
Connect a hose to the water heater drain... see how pressure/volume flow looks and acts (see if it reduces). If water flow and volume are poor at the heater drain then the only next step is to start disconnecting things... start at the heat trap nipple(s) and then swap out the water heater shutoff, etc...
If the water pressure comes out of the heater drain strongly then you would only disconnect the hot pipe from the hot heat trap nipple and work forward from there... right?
Neda Roberts
Oct 18, 2014, 04:17 PM
Thanks for the advice. We'll see how it goes tomorrow!