Storage Stratification - Would this work?

[Eric Johnson]

Honeywell has a nice cast iron 4-way valve that sells for less than $100 with the actuator, I think.

http://customer.honeywell.com/honeywell/ProductInfo.aspx/V5442N1031

(broken link removed to http://www.partsguy.com/cgi-bin/PartsGuy/V5442N1031.html)

 

[termite]

The following link shows the 4 way idea applied.

https://www.hearth.com/talk/threads/12887/

The 4 way valve servicing the tank is the lower of the two in the photo. On down in the thread are plumbing and wiring diagrams if you are interested.
This works well in my application.

 

[Nofossil]

As far as I can tell, the Honeywell 4-way lists at $120, and the actuator at $260. Maybe there are good discounts available, but my impression is that these are low-volume specialty parts compared to zone valves and circulators.

 

[WoodNotOil]

I emailed Taco and asked what the head loss for a zone valve, an electronic ball valve, and for pumping through an inactive pump were. Here is the response:

"From: joe M.
Message: Cv for the 3/4" 571 valve(zone valve) is 6.1 Cv for the 3/4" EBV valve is 8.4 Theoretically, you can have pumps in series with one pump pumping through the other with a minimal pressure drop, because a pump in line is nothing more then an extension of pipe. If both pumps were energized you would double the head, because as long as they are in series, you creating a multistage pump. Hopefully this helps you."

It seems from this information that the least head loss and the best price would come from using two pumps pointed at one another on a single line. I was going to use the Grundfos 15-58 pumps, but all of them I see online have an integrated flow check which will not allow them to be pumped through in reverse. I will have to contact my local heating supplier and see if they can be ordered.

 

[free75degrees]

Theoretically, you can have pumps in series with one pump pumping through the other with a minimal pressure drop, because a pump in line is nothing more then an extension of pipe. If both pumps were energized you would double the head, because as long as they are in series, you creating a multistage pump. Hopefully this helps you."

It sounds like he thinks you were talking about the pumps pointing in the same direction. I wonder if his answer might have been different if he knew you meant they would be pointing in opposite directions.

 

[WoodNotOil]

I don't think so. I was quite clear when I sent in the question. I described the setup as an idle pump being pumped through in reverse. I also asked if this is ever done and if it would cause any damage to the pump over time. I have the option to respond to him, so I will write back just to be sure and post the response when I get it.

BTW - I checked this out at Nofossil's suggestion. He is the one who spotted the head loss issue and thought reversing the pump would be lower. Good call!

 

[Nofossil]

I believe the Grundfos check valve is easily removable. I don't see anything in te design of circulators that would cause teh head loss to be different in one direction than the other. I know that without the check valve, you can get pretty impressive reverse flow even when you don't want it.

 

[Bob Rohr]

Yes the check is easily removed in the Grundfos, and can be re-inserted. Flowing backwards should not be a problem, just be sure it stops spinning backwards before you apply power, or you may end up with a broken shaft.

Years ago the geo guys tried pairing high head pumps in series, flange to flange, to cut down on pump costs.. For some reason they had a lot of problems with shafts snapping. The shafts are some sort of ceramic and actually break easily. Especially if you drop one

Any time you have cold on one side and warmer on the other you can get ghost flow. This is why all the circ manufacturers went to internal checks. Contractors that zoned with circs were experiencing overheating issues. The small spring check they use is an excellent stop.

It is possible to get reverse flow in hydronic piping and it may be necessary to have check protection on supply and return piping. This is especially true if you pipe off the top side of horizontal piping.

Mother nature hates an imbalance and will even allow flow in two directions in piping to try to reach equilibrium. This may or may not be an issue in your piping arrangement.

In the case of some fossil fueled systems it can cause overheating and also increased fuel consumption,if it goes un noticed. Or un-checked

 

[WoodNotOil]

Great advice guys. I'll just buy the ones w/ checks and take them out. I will have to play around with the layout a bit to see if there isn't a way to discourage "ghost flow." If I end up having trouble with it, I suppose I could always put in a zone valve to stop the flow.

 

[WoodNotOil]

Anyone have ideas on placement of pipes in the tank. Should they come through the lid in the center or can it be off to one side? Can they just come straight down or should the tee off into a horizontal pipe with holes drilled in it to spread out the flow? How far below the water line should the top pipe be and how close to the bottom should the bottom one be? Any suggestions or experience would be appreciated. Thanks