Hot Water Pressure Problem

**rep01** · 02-02-2013, 10:25 PM

Over the past several weeks I have encountered a very noticeable drop in the pressure of the hot water in the hose. Previously pressure was sufficient to run three showers at one time, now only barely one. The hot pressure problem is experienced in all bathrooms. The natural gas tank has been flushed and no sediment was found. There appears to be an atmospheric back flow valve on the cold water supply to the tank and water seems to be dripping out the vent constantly. Cold water pressure is around 100 pounds. Could the back flow valve be faulty and causing the low hot water pressure coming out of the tank? Any suggestions would be appreciated.

**LLigetfa** · 02-03-2013, 06:29 AM

What you describe as an "atmospheric back flow valve" is most likely a vacuum breaker and probably not the source of the problem but since it is dripping, it does need attention. My guess is that stirred up sediment got into the heat traps and is responsible for the flow restriction.

**rep01** · 02-03-2013, 07:35 AM

Originally Posted by LLigetfa

What you describe as an "atmospheric back flow valve" is most likely a vacuum breaker and probably not the source of the problem but since it is dripping, it does need attention. My guess is that stirred up sediment got into the heat traps and is responsible for the flow restriction.

Thank you for the reply. Based on pictures of backflow valves and vacuum breakers I have found on the various plumbing supply sites, it appears to be a backflow. Regarding the heat traps, I am not sure where they are located or how to check/clean. I am thinking about removing the valve (temporarily) and putting in a length of pipe to see if that addresses the pressure problem.

**LLigetfa** · 02-03-2013, 07:48 AM

Originally Posted by rep01

...it appears to be a backflow...

Well... it may be both that and a vacuum breaker otherwise why would it need to have an "atmospheric" component?

As for heat traps, they are easy enough to find with google.

http://lmgtfy.com/?q=heat+trap

Also frequently discussed here.

http://lmgtfy.com/?q=heat+trap+site%3Aterrylove.com

**Gary Swart** · 02-03-2013, 11:21 AM

This is not the problem you have described, but 100 psi is way too much pressure. Over 80 psi would need a pressure regulator valve.

**rep01** · 02-04-2013, 06:17 PM

Thanks for all the responses. Tonight I used pex and a couple of shark____ fittings and completely bypassed my hot water tank in the plumbing system. Part of what I bypassed was a drip valve that is used to prime the floor trap (originally thought it was a pressure valve). Pressure problem disappeared. So I reconnect everything with copper and omitted the drip valve - no more problem - it was a faulty drip valve. Last thing I will do is turn the pressure regulator valve back to 80 pounds. Great forum and suggestions!

**LLigetfa** · 02-04-2013, 06:35 PM

I find it hard to believe that a trap primer would cause pressure loss. I'm more inclined to believe that with your draining and disconnecting/reconnecting that you knocked loose whatever was stuck in the heat trap.