wisconsinben
New Member
I'll apologize in advance for the long post, but I've already done a lot of trial and error experimentation that might be helpful to solving my issue.
I have a Moen PosiTemp Shower in the master bathroom. Connected to the hot water supply (just before the PosiTemp) is a hot water return line. The original construction of the house had a straight line for return (no backflow prevention valves, no recirculating pump). At that time, the hot water recirculation worked great, but the PosiTemp shower had intermittent hot water. It was almost as if the PosiTemp couldn't decide if it should pull from the hot water supply line or the recirc line. Closing the shutoff valves in the recirc line eliminated the problem, but left me waiting for hot water everywhere in the house.
The next step was to install a swing valve to prevent backflow in the recirculating line and, of course, open the recirc line shut-off valves. This seemed to work, as the PosiTemp shower now functioned properly, however the swing valve was too restricting for the gravity-fed recirculation...so I was still waiting for hot water at all points in the home.
The next move was to add a recirculating pump, to overcome the restriction of the swing valve. I've installed a Grundfos Auto PM pump just above the water heater on the recirc line. Pump works great. I have instant hot water at all locations, however now I get constant warm water through the PosiTemp shower. Turning the handle to the full hot position yields only lukewarm water. I've again tested by closing the shutoff valves in the recirc line and everything is fine (if you don't mind waiting for hot water, of course).
The other thing that might add some complexity to this is that I have dual 40gal water heaters that are connected in an unorthodox manner. The link below has three pics to show how the water heaters are connected, where the recirculating line comes in and where the far end of the recirculating line is connected (just below the PosiTemp valve).
http://1drv.ms/1vt6UQJ
Any insight would be GREATLY appreciated!
I have a Moen PosiTemp Shower in the master bathroom. Connected to the hot water supply (just before the PosiTemp) is a hot water return line. The original construction of the house had a straight line for return (no backflow prevention valves, no recirculating pump). At that time, the hot water recirculation worked great, but the PosiTemp shower had intermittent hot water. It was almost as if the PosiTemp couldn't decide if it should pull from the hot water supply line or the recirc line. Closing the shutoff valves in the recirc line eliminated the problem, but left me waiting for hot water everywhere in the house.
The next step was to install a swing valve to prevent backflow in the recirculating line and, of course, open the recirc line shut-off valves. This seemed to work, as the PosiTemp shower now functioned properly, however the swing valve was too restricting for the gravity-fed recirculation...so I was still waiting for hot water at all points in the home.
The next move was to add a recirculating pump, to overcome the restriction of the swing valve. I've installed a Grundfos Auto PM pump just above the water heater on the recirc line. Pump works great. I have instant hot water at all locations, however now I get constant warm water through the PosiTemp shower. Turning the handle to the full hot position yields only lukewarm water. I've again tested by closing the shutoff valves in the recirc line and everything is fine (if you don't mind waiting for hot water, of course).
The other thing that might add some complexity to this is that I have dual 40gal water heaters that are connected in an unorthodox manner. The link below has three pics to show how the water heaters are connected, where the recirculating line comes in and where the far end of the recirculating line is connected (just below the PosiTemp valve).
http://1drv.ms/1vt6UQJ
Any insight would be GREATLY appreciated!