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[mw10737]

guys,  just added (2) pumps to my empyre system.  I stacked two gunderfous 26-99 pumps, feeding out of furnace with 1 1/4, then pex is 1".  Running 110ft to house .  I can tell you this, its amazing how quick recovery is with furnace and heat exchanger for DHW.  I think the wood usage has cut in half... Its amaxing getting that return water back there faster and taking less heat of of return... makes a huge diffirence.  VERY HAPPY with results .  Can run furncae and take showers and i only see maybe a 10 degree drop in return water temp. Boiler temp normally doesnt even drop.  Guess stacking these two pumps is the ticket..    opinions?

[RSI]

You added 2 more? How many total do you have now? One of those should be enough normally.
How many heat exchangers do you have in the house? Do you have a plate heat for the DHW? if so what size?

[Scott7m]

The flow of water has no bearing on the btu load of your home or domestic water needs, you can circulate the water 200gpm or 10gpm and your home still requires the same amount of btu

I have no idea why your wood usage seems lower, perhaps because it's so mild right now?

[RSI]

The flow of water has no bearing on the btu load of your home or domestic water needs, you can circulate the water 200gpm or 10gpm and your home still requires the same amount of btu

I have no idea why your wood usage seems lower, perhaps because it's so mild right now?

If using a 10 plate and a small pump there will only be a couple GPM at the most and running hot water will take all the BTU's available. Going to a larger pump(s) will force the water through at a higher rate giving enough BTU's to keep up with demand.

If that is what is happening, getting a bigger plate would allow to run one smaller pump and save $20 or $30 a month on electricity.

As far as wood usage, it might be from getting a lot better mixing in the boiler tank.

[Scott7m]

I understand that but I doubt he has a 10 plate, but half the wood? 

I have used 10 plates and 20's here at home just trying to see if there was a difference.  The 20 made a bit hotter domestic water, I've also used several different pumps and I've never noticed any making a difference in efficiency

[RSI]

How many feet of pex were there with the 10 plates and what pump was on the system.
I have seen a system with a 10 plate and about 150' from the house that the boiler water was under 100 degrees coming out of the plate.

[mw10737]

Guys.  Using A 20 plate for DWH.  And have a 12X12 (90,000 BTU) in my garage,, and a 20X24 in my house furnace.  Problem last winter was a huge temp drop out of my registers when showers were going. So therefore I wanted to increase flow.  Now furnace can run and showers going... washing clothes.. dishwasher going. and I have no temp drop in registers.  Basically what I think is happening is now that the flow is much higher and  im not losing near the heat from the 20 plate.. and is getting the water back to boiler quickly and not dropping boiler temp more than 6-7 degrees after 5 people take showers,  and yes it is using 1/2 the wood.  It only makes sense though.. if water can get back to boiler with minimal heat drop it isnt going to drop boiler temp that much....hence not having to run near as much, therefore the less wood consumption... this thing is working great.

I have 3 pumps on boiler, but only run stacked pumps in the fall-winter..... and through the spring and summer will run the smaller single pump for DHW only..  tell me if what im saying doesnt make sense,,, but it is working good so far. Im runnung 150 ft to house then another 100 ft before i get to basement.  So I have a long distance to run. 

Also I have both my  furnace blowers and my pumps and wood furnace is running off of a wind generator with battery bank.  And so far with the dual pumps running it hasnt seem to use that much more from my inverter. 


I have a temp probe on feed line and return line.;  the most i can get as a temp drop running showers and furnaces is 7 degrees.   too me that is extreamly good...  keep the feedback coming ..     

[RSI]

So you have about 500' of 1" pex and 3 heat exchangers? Are there any zone valves or many elbows?
What model is the original pump?
Did it always work the same way or has it been getting worse

[mw10737]

6 elbows..  always worked the same.  was a smaller pump... max flow of 17GPM

[RSI]

Grundfos 15-42?

[mw10737]

RSI:  Here are the specs

Three Speed High Performance Circulating Pump

•Removable Integrated Check Valve
•Built-in motor protection for longer life
•Quiet and low power consumption
•Prevents thermal siphoning
•Pump Housing: Cast Iron
•Voltage: 115 V, 60 HZ. Power: 100/70/55w. Motor: 2 Pole, Single Phase
•Min Fluid Temp: 36° F (2° C). Max Fluid Temp: 230° F (110° C). Max Flow: 17.9 (U.S. GPM). Max Head: 19 feet (head). Max Working Pressure: 145 PSI
•Insulation Class: H 356° F (180° C)


Vendor: Stiebel Eltron

[mw10737]

Do you think it shouldnt work?  does what im saying make sense? 

[RSI]

That is a Grundfos 15-58.
That is too small for that much pipe. 
I would have thought that one 26-99 would have been sufficient. Have you tried just running one of them by itself?

[Scott7m]

No..  Because its still pulling off the same # of btu to heat your water and your home, the amount of heat your applications require did not change. 

Example.....   Let's say it takes 50,000 btu to heat ur home for an hour.  The stove still had to produce the same number of btu, the speed of the water may have increased lowing your delta t across each appliance but the same # of btu were used.  Let's say before you had a delta t of 30, and now its 10, you are sending the water back to the furnace hotter than previously, but there is more water moving, so no change. 

Would it improve things like registers cooling during showers? Yes. Because more gpm are moving bringing more btu's in, lowering the delta t

[Scott7m]

You def had to small of a pump for the distance....  Maybe ur flow was so crazy slow you had huge delta t's but I still can't see it burning less wood, half would be s miracle, I'm just thinking, if saving half the wood were so simple, why don't we all just install the biggest pumps we can?