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[brandontravis]

has anyone used a recirculating pump on the domestic water side of hot water tank without a return line back to tank? from what i have seen it seems to me that hot water recirculating back thru the cold line would give me warm water when i use the cold water. here is a link to pump that i was looking at  http://www.pexuniverse.com/grundfos-up15-10su7p-tlc-comfort-system-595916

[Wood Nutt]

I don't have one, but have read about them.  my understanding is they only dump warm water in when the temp drops, but does not circulate continuous so it must use some sort of temperate valve.  You might have a short burst of warm water from the cold side, but I would think it would cool off pretty quick if you only wanted cold water.  But, remember that the purpose is to have quick hot water.

If you install one, post how well it worked.  I have a long run from my heater to the shower and the water has to run at least a minute before I get hot water to that end of the house.

[brandontravis]

ok thanks i will post how it works if i install one

[artbaldoni]

We have used these in small office buildings with good results. You have warmish cold water for a couple seconds only, but have hot water right away.
http://www.lowes.com/pd_77814-18701-500899_4294856716+4294954937_4294937087?storeNumber=1710&selectedLocalStoreBeanArray=%5Bcom.lowes.commerce.storelocator.beans.LocatorStoreBean%4013a613a6%5D&productId=3135231&ipTrail=67.234.45.25

[juddspaintballs]

I have a stainless Taco pump circulating water from the hot water output of the tank via a tee down through the side arm heat exchanger and back into the drain valve.  I had it reversed initially, but kept getting fluctuations in temperature.  Even with a tempering valve and the pump setup as I described, I never have just warm water and it stays a constant temperature.  The recirculating pump setup I use keeps the entire tank of the water heater always hot and since it's not relying on thermosiphon to heat the tank through the sidearm, it heats it up at an almost on-demand rate but with a 60 gallon buffer tank full of hot water.

[brandontravis]

ok i have read some good things about installing a recirculating pump, but here is my problem i dont know if it would be better to install the pump or install a plate exchanger. my issue is it takes about 2 minutes to get hot water to the far end of my house and after 1 shower i need to wait about 4 hrs to let 90 gal hot water tank heat back up when i am using the sidearm exchanger fed from boiler when using electric instead of boiler it still takes about 2 minutes to get hot water and i can take 3 showers before running out of hot water. if i would install plate exchanger i would still use sidearm exchanger also. which route would you go?

[LittleJohn]

According to the literature (WHY did I read the manual)  that grundfos pump uses the cold water line as a return and uses a timer to control the pump.  It should work as long as you can schedule the pump to turn on say 5-10 minutes before your morning shower.  If I had mote time to invest in play around with my domestic Hot water and boiler I would try to work it out so that when I turn my alarm clock off in the mornign the pump comes on to "preheat" lines from water heater to shower, that way I dont waste 5 mintues of water before i shower; and of coarse for the weekend a push button so I can sleep in a little bit

[Michael]

I put a pump at the kitchen which is the far point of the plumbing. Pull from the hot side into a separate line back to a tee that feeds the plate exchanger and then into the hot water tank. It has a thermostat and timer ( I don't use the timer ) and we have instant hot water all the time.

[ITO]

 I have used the Grundfos recirc valve in my slab homes bedroom bathroom since 04, it works well, mine is controlled by a timer as LittleJohn said, there are some limitations with that but not bad. If I would have thought about how far this bathroom (which is the shower we usually use) was away from the utility room I would have run a recirc line but this was done after the fact when we noticed how long it was to wait for hot water. The pump is in the utility room so there is no noise in the bathroom which would be a problem because that wall shares with our bedroom wall. We have a conventional septic so I hated standing there and listening to all the water just pumping away into the ground.

[edward_2]

 

[CountryBoyJohn]

ok i have read some good things about installing a recirculating pump, but here is my problem i dont know if it would be better to install the pump or install a plate exchanger. my issue is it takes about 2 minutes to get hot water to the far end of my house and after 1 shower i need to wait about 4 hrs to let 90 gal hot water tank heat back up when i am using the sidearm exchanger fed from boiler when using electric instead of boiler it still takes about 2 minutes to get hot water and i can take 3 showers before running out of hot water. if i would install plate exchanger i would still use sidearm exchanger also. which route would you go?

Mr. Brandontravis, I have a plate exchanger located before my water heater, which is turned off at the breaker.  It takes less than 1 minute to get the hot water to my shower which is the furthest fixture from my water heater.  I have unlimited hot water.  I filled a 400 gallon hot tub with hot water.  It was 110 degrees when it was done filling.  I don't understand why anyone would want to buy a pump in order to get a sidearm to function well.  It's another thing to go wrong.  I can understand how some people would want a sidearm in low-use situations, that's fine.  Or even if they were to use both.  BUT, installing a pump to get a sidearm to recover more quickly has me scratching my head!  Just get a plate exchanger.