Print

[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

[baldwin racing]

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

mark sounds like the pump is junk and not pushing the water....yea it may be on but may not be working....check it for junk close valves unbolt 4 screws and pull off motor see if you have junk in pump impeller....also was the exchanger plugged? check the pump first sound like you need to buy a new one....
kelly

[willieG]

pump in the house has potential for continued air lock and may need much more than just "turning it on" to get all air out of system

pump is undersized as it looks as though the head pressure for that pump is at or above its capacity and has absolutely no room for adding anything on such as domestic exchanger or a floor loop.

dont just "buy" a 1 inch pump. if you can not figure out your head pressure and the gpm you want to deliver to your home, take all the information such as pipe size, length of pipe in system including  all things in the lines such as exchanger model, elbows, tees, valves etc. and take them to  a professional at yoru pump store and he will tell you the best pump for your system. be sure and tell him also that you have an open system.  moving water is not as simple as "buy a pump" and go

[RSI]

Is it possible to move the pump to the boiler instead of in the house? If you are that close to the top of the water level, the pump won't be happy.

It is probably air in the pipes keeping it from circulating. Until you get it all out, the pump is having to lift the water and the 007 can only lift a max of around 10'. Once you get the air out the return water going back down will pull and and get rid of the additional head pressure due to lifting the water.

Also, I would either get a larger pump or add another 007 in series. (doing another 007 at the boiler and leave the existing would probably be easiest)

[boilerman]

I think the main cause for air locks and pump failures is the fact that most people just plug their pump in and expect them to start pumping water.
This may work with pressurized systems.
Most OWF systems are open, non pressurized systems, so the pumps and PEX loops need to be filled and purged under pressure on initial install or if a pump replacement has taken place. Household domestic pressure (typically 40 PSI) should be connected to a drain valve teed somewhere into the loop, with water pushed back to the OWF through both the return line and the supply line by opening and closing the supply/return valves at the OWF (yes backwards through the pump) before ever plugging the pump in for the first time. Without doing this, the water lubed cartridge never fills correctly and all the air may not be pushed out of the lines and exchangers for full water flow, which is why pumps can also fail in short order. I have even silenced noisy pumps by doing this process. The pump in a non pressurized system should be installed in the supply line and at the lowest point for most feed pressure.

[vamark]

Thanks for all the ideas!
I should have maybe givin a few more details. This is a new install with a new pump, new heat exchanger etc. I had purged the lines from the stove through the heat exchanger to the system drain and then from the furnace to the floor drain. After doing some calculations I believe the pump is infact too small, I thought it would be close and since it was not ever used and just laying new in the box I thought I'd try it first. I have ordered a Taco 2400-20WB.

[vamark]

Just a little more follow up. While waiting for the new pump I thought I would try purging the air out of the system better with a garden hose pushing water back to the stove thru supply and return lines. After purging for about 30 minutes on the supply I turned the 007 pump on and had water flow! I still plan to install the bigger pump since this loop will supply water for 2 HX's and DHW I will use the 007 pump for my garage loop.

Thanks guys you all really know your stuff!