Re-cir?

Jlamb

Recently I visited a job site where they had a 006 taco re-cir pump piped into the supply Side or hot side of a water heater. "Pumping away" if you will. My issue with this is the pump was about six feet down the line pumping into various manifolds. thishouse had 4-5 baths, kitchens etc. 3/4" hot main Ran about 75' and the re-cir line coming back to the water heater was 1/2" ran approx 100'. So A.) I can't imagine this pump would have enough head to even reach the re-cir line and B.)is pumping away the correct way to re-cir? I have always seen pump on return Side/ cold water side.

icesailor

Heads Up:

"Head Pressure" is a measure of restriction. Not the pressure needed to overcome the pressure in the system. I've never seen a recirc. system with a 006 that didn't work. Though I would have put the pump on the return because it will "see" cooler water.

Where you CAN have a head issue is where I had one recently. I converted a 50 gal. electric water heater to a storage tank and a 199,000 Noritz instantaneous gas water heater as the heat source. I connected the hot water outlet from the Noritz at the cold water inlet to the tank where I always do. The owner complained that he ran out of hot water when he was washing out his still. I found that when the water was being used, that the pump couldn't overcome the resistance of the 60# cold water going into the tank when it was running. Stop the water and there was no more problem. So, because electric water heaters have 1" NPT tapping's for the elements, I removed the lower element and installed a 1" nipple and reduced it to put a boiler drain and a washing machine hose to connect into the cold of the water heater so the pump pumped through the Noritz with no tank restriction. Problem solved.

When pumping through the tank, there is no pressure rise to overcome when the water is flowing or stopped. When connected at the top, the pump had to overcome the flowing pressure. If the water wasn't flowing, the static pressure was equal on both sides of the pump.

I have installed pumps like this for years. I never had a problem. Maybe they all had the problem but it wasn;t noticed because the inlet cold flow wasn't as high and they weren't trying to use as much hot water.

I learn every day. Still.

Jlamb

Re-cir

Ok i should provide some other information.  It is an Eternal water heater 200k btu's (no storage).  Customer hasn't necessarily complained about this begin an issue, but i would also imagine now your creating a potential restriction if the pump is not running. Going from 3/4" to whatever the inside diameter of the pump is. I agree i learn something new everyday, it's nice to have other people's opinions and thoughts.

icesailor

Pumping away, far away:

It seems that what you are describing is a way to avoid a Buffer Tank. And won't save squat on ca$h and defeats the purpose of the indirect. If you pump into the cold, it should trip the flow switch and start the burner while the pump is running. .