Hot water problem

[raptor78]

I'm a DIY without plumbing experience, thanks in advance for your help. Here's my problem. I turn on the hotwater the water, the water flows for a few seconds and then slows down, I hear a bang in the pipes and then the water starts flowing normal again for a few seconds, this repeats until the water stops flowing for longer periods of time followed by a progressively louder bang in the pipes. To stop this I leave the sink, shower, or dishwasher running and I run to a different sink and turn the hotwater on, the flow gradually improves until hot water flows without a problem in both thinks, then everything is fine for a while. I have no problem with cold water and this problems seems to be most prevalent upstairs on the second floor as I get further from the hotwater tank in the basement. I'm looking for advice to repair the problem, if it's something easy I can do myself and save money that would be great.

 

[raptor78]

I've been given advice to drain my hotwater tank, I'm not sure if this would help? To drain my hotwater tank can I just turn off the water valve that fills the hotwater tank and then turn on the hot water at a sink until it's empty?

 

[havasu]

That won't drain the tank, especially when it is in the basement. You need to connect a garden hose to the drain valve at the bottom of the tank, and using 5 gallon buckets, fill, go outside and dump it. Then return and repeat, unless you have a pump that you could use in the basement.

 

[raptor78]

do you think this might help with the problem I'm having?

 

[johnjh2o]

Sounds like a loose washer. It could be in the faucet or in the hot water line feeding the sink. Try turning the valve under the sink. Have you had any work done on the plumbing lately? It could also be debris in the line feeding the sink.

John

 

[raptor78]

Thanks for for the info John. What do you mean "try turning the valve under the sink", just to clarify further this problem is happening at every sink, could one bad washer effect them all?

 

[raptor78]

no I haven't had any work done ever, the townhouse was built in 2005

 

[raptor78]

also I haven't noticed any leaks

 

[johnjh2o]

Sorry I thought it was just on one fixture. I would first check the valve on the heater. There could also be something in the heat traps on the heater. That's something a plumber would have to repair. It's almost impossible to determine what the cause is with out being there. But if it's happening at all the fixtures it's in the main line after the heater or feeding the heater.

John

 

[Caduceus]

I came across the same situation at a service call years ago and found exactly as John had stated. The washer inside the valve to the hot water tank supply (cold side) was loose. Without any plumbing experience, do you feel comfortable changing the washer or installing a ball valve?

 

[raptor78]

Yes I'm comfortable working on this kind of stuff if I can get some good directions. Thanks for the information!

 

[raptor78]

The valve really does sound the like problem, it's like the pipe aren't primed because the water is leaking back into the tank, is that basically the problem?

 

[raptor78]

but unlike he problem you fixed caduceus my problem is the valve on the hot water side, right?

 

[phishfood]

No, there is a loose washer that is "hanging out in the flow". If the pressure is low enough on the output side, such as when you turn on several faucets, the washer is forced out of the way. The sudden pressure spike created when this happens causes the pipes to vibrate and bang. If the pressure stays relatively stable, such as when you use just one faucet, the loose washer restricts the flow of water.

Edit to add: Most likely, this is in the valve that supplies the water heater.