Gravity Line Not Working Properly

SPY

For 15 years we got hot water to the faucets in the back of our house within 15 seconds; to the shower in 5 seconds. I always understood that happened because we had a functioning gravity line. We do not have a recirculating pump. Last month our Rheem water heater showed significant rust in the bottom, so our local plumber installed a Bradford White as a replacement. Some minor plumbing and gas line changes were made to bring to code. It now takes 30-90 secs to get luke warm (90deg) to those same faucets and 1 to 2 minutes to get hot water. The shower now takes 15 - 30 secs to get hot water.
Our plumber claims they did nothing to alter the effects of the gravity line, yet it doesn't work like it use to. They bled air out of the line, and installed a valve on the gravity line to insure water goes one way into tank. I really don't want to install a pump after reading so many negative comments. Any suggestions?

JUGHNE

Pictures of WH, showing all the piping might explain.

rick in Alaska

If the line isn't bled at the point just before it enters back in to the tank, then it won't work.You can't bleed it at the faucet upstairs. You said they did some minor piping changes, so we need pictures to see what it looks like.
Rick

Larry Weingarten

Hi, If the new heater has heat trap nipples, those could be stopping flow also.

Yours, Larry

SPY

Thanks for your quick responses. Hopefully these pix will help.

Larry Weingarten

Hi, I'd remove that swing check valve and use the ball valve up higher to throttle the flow down, so you still get fast hot water, but not enough flow backwards through the line to affect your hot water temperature. It will take a few days to get it right. Once done, remove the handle and tape it to the pipe, so it doesn't get played with. Gravity flow is so gentle, it can be stopped by the swing check.

Yours, Larry

rick in Alaska

I would have to say I use the swing check to keep any reverse flow from happening, especially if the last fixture off the return is very close to the end of the line before it gets back to the water heater. Unfortunately, I can't tell if the check valve is going the right way. See if you can get a mirror behind it and make sure the arrow that is on it is pointing toward the water heater.
The drain valve with the green handle on it next to the panel with the orange tape on it is where you need to bleed it, and you can also use it to check if the check valve is installed properly. Close the valve above it that comes out of the wall, then open the green handle valve. Nothing should come out. If it does, the check valve is backwards and needs fixed. Then open the upper valve and then the drain valve again. You should get good water flow. Let it run long enough to make sure there is no air in it. If everything is right at this point, it should start gravity flowing again.
Also, have Justin clean up those solder joints please.
Rick

JUGHNE

IMO, I think you need/want the check valve.
First test/check that it is installed in the right direction as per Rick's advice.

If that is good then you may have to take the bonnet off the check and drill an 1/8" or slightly larger hole in the swing flapper. This induces gravity flow if there is not enough to open the check slightly.
That 1/8" hole will allow a small flow towards the upstairs as you run hot water but not enough to notice, you are mixing H & C at a faucet anyway. Unfortunately without a second valve you have to drain the tank.

Or there may be anti gravity migration ports in the top of the WH to prevent flow and thus "save" energy.
The hole in the check valve flapper may over come that pinch off.

I do not have a hole in my check valve flapper and can throttle down the return with a ball valve to just about nothing. But I have a plain jane tank with wide open ports on top.
I have about 60' of horizontal pipe on a gradual slope down and a total of about 8' total vertical drop.
Not insulated near the tank for cooling effect. Don't know if I need that cooling leg or not.....actually just ran out of insulation.

SPY

The check valve is pointed correctly toward the WH. I close the ball valve on the gravity line and opened the green handle drain valve and nothing came out. I hooked up a hose to that same drain and opened it to drain for five minutes. Within seconds, the water coming out of the drain hose was hot. 30 seconds later it was very hot, but I let it run. Closed the drain and tomorrow should tell me whether the line is working again. I really appreciate all your help and guidance. I'll post how it going.

SPY

No luck! It is still taking way too long to get hot water to the sinks in the back of the house (up to 2 minutes). Do I just have a failed gravity line? Should I continue to try draining the gravity line? Will installing a pump improve performance? It is frustrating to watch so much water go down the drain before getting hot water, especially when you live under severe drought restrictions.

JUGHNE

I would try the 1/8" hole drilled into the check valve flapper.
You would have to drain the tank, the top of the check can be removed, use 2 wrenches. That might allow enough phantom flow.

SPY

Jughne, thanks for your continued support. I was unable to remove the top of the check valve. I'm fairly strong, but it would not budge. Since hot water delivery is still extremely delayed, I will install a pump. Thanks again for everybody's support.

Larry Weingarten

Hi, An old plumbers' trick I use is to figure out how to get two wrenches on the thing that needs to break loose. Then use a pry bar or long screwdriver between those handles. It multiplies your leverage and often lets you get something done that otherwise wouldn't happen.

Yours, Larry

JUGHNE

Impact driver with correct 6 point socket should get it off.