We just replaced our hot water heater because we were getting a lot of mineral deposits in our fixtures throughout the house because the hot water loop returned to the bottom of the tank and always mixed up the sediment in the tank. Our plumber is trying to install a recirculation pump without using the drain valve (at the bottom of the tank) as the return for the loop. He is trying to explain to me how putting a pump in different places can circulate the hot water through the house and back into the hot water heater. Is this even possible?

Here is the current setup, which isn't really working. Inconsistent water temperatures, and some times little to no hot water.


Thanks for your help!!

  • circulate the hot water through the house and back into the hot water heater ... that is not what the diagram shows – jsotola Oct 27 '18 at 23:48
  • Well, that is part of the problem. The drawing is correct, and with our last water heater, it went into the drain valve at the bottom of the heater. He has it set up this way, which isn't working. I guess what is the best thing to do, pipe it again and have it run into the bottom of the tank so it is pulling from the tank, goes around the house and is pumped into the bottom of the tank? – rcm87 Oct 28 '18 at 22:17
  • goes around the house .... this statement makes no sense in the context of circulating hot water to faucets ..... is there something that you are not telling us? – jsotola Oct 29 '18 at 0:57
  • So my understanding is we have the Kitchen, Powder room, and Master bath on this hot water loop. We have a couple other bathrooms that are not on the loop because they were too far away. I believe out setup is like this [link] diyplumbingadvice.com/waterheaters/hotwaterrecirc.shtml Does that help? – rcm87 Oct 29 '18 at 3:00

You can use the cold water inlet to connect the recirculator input by a tee (if your boiler don't have a half-height water inlet purposed for recirculation return), just put one-way valves on both recirculation return and cold water feed.enter image description here But usually, boilers has an inlet at about half-height to connect the recirculation return.


black rectangle on the left represents the boiler
you need both the 1-way valves because you:
don't want cold water do go 'backward' trough the recirculation loop
you must avoid backflow to cold water supply
boiler hot water oulet and cold water inlet are on right side but can be on any side of the boiler.

  • This is how most places do it, a timer is used to cycle the pump on and off every 15 minutes or so during times of normal water usage and less often in the middle of the night to save $.+ – Ed Beal Dec 26 '18 at 17:04

Not sure why you need a circulator pump unless you demand instant hot water. If that is the case, get point-of-use under-sink heaters.

The simple answer is to buy a water heater with a hydronic circuit which works independently from the "fired" tank. That would eliminate the loss of a drain valve.

Most homes do not have insulated pipes, and pipe insulation makes a big difference in the containment of heat in the hot water piping.

But I still do not understand the need for a pump.

  • Instant hot water and higher energy bills. – Harper - Reinstate Monica Oct 27 '18 at 18:46
  • It is a pretty large house, and our bathroom has almost instant hot water, yet kids bathroom, which is not on the loop, takes a good minute or two to get warm enough to shower. What is sounds like is just scrap the whole loop idea and just wait for warm water? – rcm87 Oct 28 '18 at 22:19

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