under floor heating

I had access to half a dozen 1-1/4 diameter steel pipes so I ran them under the kitchen floor, as my wife complains the floor is cold since I installed the coal boiler in the garage. I only have 1 zone for the entire house so I used the "taps' from a disconnected radiator. Got it all hooked up and now the water just doesn't bother to run through it Should i put a spare Taco pump on it and will it draw water through the other main Taco pump (I would need it to) when the main Taco is not running? Thanks!

Is your existing system a monoflow setup?

It has a main line in and out with each radiator teeing off from the pressure side and the return side.

did you put a vent on it to get rid of the air ,all of the air either that or did you put a purge station on the line ??

I thought about a vent of sorts but did not know how to vent all six 8' pipes? I ran water through before making the last connection but may not have got out all the air and I need to prevent it in the future I guess

Monoflow systems are very sensaive to air, plus it is questionable if there is enough pressure drop between the two tee's to cause flow through 50' of pipe. I would start by adding a ball/purge valve just before the correction to the return tee.

I do have a ball valve there, should I close it off a bit? I have a spare Taco pump, should I add that at one end or the other? - Thanks!

Adding a circulator won't help if there is air in the loop. You need to add a means of purging the air out.

Rob, Even if the pump is positioned in a vertical section that is always full of water?

Even if the circulator is as you describe, it won't "push" an air pocket out of the system.

if you have a flooded suction on the circ it will push the air around if it is less than 6or 7 ft above the circ taco 007 aprox 8' head

I could turn it into a "flooded suction" system long enough to get the air out

coalmeister wrote:I thought about a vent of sorts but did not know how to vent all six 8' pipes? I ran water through before making the last connection but may not have got out all the air and I need to prevent it in the future I guess

You will probably have to install a tee in your "radiator" at the high point to vent the air. 1-1/4" pipe is hard to vent by pushing the air with water even with a purge valve. The volume of water needed to purge is greater than the average purge valve can handle sometimes.

A tee with a reducer and a 4 inch nipple will make a great air collector. I will often use one and put a elbow on top and extend my air vent to get easier access. you can vent with a small ball valve or coin type air vent.

Was this an old MONO FLOW SYSTEM or was it originally dedicated supply and return piping?

it makes a difference and Ill bet the rest of the system will fail if you get it wrong

Thanks for the help guys, I got it working! I drilled an air relief hole in the connector pipe between 2 of the main pipes and tipped the pipes up one end at a time, and "walked" the air out of each pipe going pipe to pipe to the relief hole. It actually works pretty well now, the floor is 81 degrees and I have not even insulated the pipe area yet. The floor was about 60-65 before. Cost me less than 50 bucks in fittings & connections. Next summer when the heat is off I will do the whole kitchen.