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[vamark]

Hi guys,

I built my outdoor furnace and finally got it hooked up to my house and now I can't get the water to flow .
I'll tell you how the system is set up and hopefully someone can help me out. The furnace is 75 ft from my house and another 35 ft to the air to water heat exchanger in my duct work, the exchanger came from a outdoor wood furnace supply house. I run 1" pex and used a Taco 007 pump I had laying around and installed the pump in the house. When I fill the furnace to proper water level the water will flow slowly to the pump by gravity, from there the pump needs to push the water up to the heat exchanger which is about 6' then back to the furnace it will barely pump the water through the heat exchanger and not a chance it will go back to the furnace. I'm guessing the pump is too small but I can't imagine a pump of even twice the size working but maybe it will.
Anyone have any input on how to get this thing working?
I'm thinking about trying 1 of those 1" fresh water pumps from Northern Tool.

Thanks
Mark

[dwneast77]

I wonder if your pump is just air bound??  Try turning the pump off and back on.  007 should push enough water.  I have a run using 007 that's about 100' through 3/4" PEX.  My line feeding my house is 1" PEX a little over 100' using 009 pump, which from what I understand doesn't push as much water but has more power.  Both setups work great.  If you didn't cross any lines......  Do you have a flow check installed that might be backwards?  Is the pump flowing the right direction??  Is the pump old? new? used??.  Is it actually functioning properly?  A couple if ideas to check out.  Any other details you can provide can only help a diagnosis.  Good luck!!

[jerkash]

I believe your pump is big enough, but with gravity pushing water to your pump, it may not be enough.  Move your pump to your furnace and it should work like a charm.
Keep us posted

[MattyNH]

 Sounds like to me the system is air locked  or the pump is junk....You said you had a pump laying around.. With that saying..Is it a used one?, That could be on its way out. Has the pump been exposed to the elements by just sitting there? When my buddy bought his OWB bran new..Fired the boiler up..No water flow...Pump was seized up and thats bran new!..My best bet is that your pump is junk..Im about the same distance as you and I use a 007 pump..

[willieG]

if the footage is right (and one way) that would amount to 220 feet round trip + the 6 foot rise + valves, fittings  and head loss for the exchanger too, lets round it off to 240 feet that puts you in the over 75 percent of the pumps curve to get 5 gpm (once all the air is out)

yes your pump should do the job, if you get all the air out, however, it is desirable to stay at or below the middle of your pumps curve so it is not working hard and prematurely wearing out.

being this close to the pumps max output may make adding another "appliance' such as domestic heat exchanger impossble

a little  bigger pump would probably make everything work a little better. perhaps a model with three speeds and the lowest speed with an output jsut above what you now have. this would leave room to add 'appliances" as you needed to

[vamark]

Thanks for the ideas and suggestions! I did some more figuring and decided to get a bigger pump since this line will be eventually feeding 2 heat exchangers and domestic hot water. I ordered a 2400-20-WB I hope that will do the trick.

[Michael]

I used a wet dry shop vac on the return line to help with the airlock that I had. Worked great.

[vamark]

I have a drain in the house that I can hook a garden hose to and push water back to the stove to get out the air. I'll try that also.

[dwneast77]

WillieG - The e-mail feature here doesn't show your e-mail address for me to send picture using my e-mail software and it also doesn't allow attachments within this site's e-mail feature.     So I looked back to find this thread.  Easiest solution I could come up with and a relevant location for it I guess. 

The supply lines come up the left side to the top manifold and then it wraps around to the return lines.

I'm thinking about re-piping so that the boilers are in a series.  It was recommended to do it that way but I thought this way would be better so I could isolate a boiler easier if needed.  I think I could rework the piping at the manifolds to make it work that way.  My biggest obsticle is the thermostatic valve and limited space to work with there and a doorway very close on the left.  I'd like to have the option to run them either way.  One thing is for sure.  With the issues I've had with the CB, I have to be able to isolate if welding is needed again.

Jeff

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