Long winded question about radiant floor heating

[Windwalker7]

First off, I'm heating my home with a OWB.

I currently have radiant floor heating set up under one room in my home. I have two 1 inch Dia. 20ft. long manifolds. (One is the return) The manifold has five 160 ft. loops of 1/2 pex. I have a booster pump for this, its a taco 007. The main pump is a Taco 011, pumping from the OWB. The OWB is 133 ft. from the HX in plenum.

Instead of a closed loop, I have water piped in from OWB to a water to air HX in my plenum. When it leaves that HX, it goes under the floor in that one room and then returns to OWB.

I basically just winged my set and it does work well except I'm losing about 25* on the water's return. I feel I would burn less wood if I were to make the radiant floor a closed loop by using a water to water HX right after it exits the water to air HX in plenum.


I admit I don't fully understand what all I've read in different threads about pumps, head, gpm flow rates, BTU's etc. They might as well be written in German. I just don't get it!

My questions are if I need a expansion tank if I have a closed loop system?

I really have no idea what the water pressure is, or will be, to charge the expansion tank to.

To those who have a OWB set up with radiant floor, do you have an expansion tank? And if so, what is you water pressure?

I'm guessing about 15lbs. If I put 15lbs. of pressure in the expansion tank and that pressure is not enough, what will happen?

 

[AKKAMAAN]

First off, I'm heating my home with a OWB.

I currently have radiant floor heating set up under one room in my home. I have two 1 inch Dia. 20ft. long manifolds. (One is the return) The manifold has five 160 ft. loops of 1/2 pex. I have a booster pump for this, its a taco 007. The main pump is a Taco 011, pumping from the OWB. The OWB is 133 ft. from the HX in plenum.

Instead of a closed loop, I have water piped in from OWB to a water to air HX in my plenum. When it leaves that HX, it goes under the floor in that one room and then returns to OWB.

I basically just winged my set and it does work well except I'm losing about 25* on the water's return. I feel I would burn less wood if I were to make the radiant floor a closed loop by using a water to water HX right after it exits the water to air HX in plenum.


I admit I don't fully understand what all I've read in different threads about pumps, head, gpm flow rates, BTU's etc. They might as well be written in German. I just don't get it!

My questions are if I need a expansion tank if I have a closed loop system?

I really have no idea what the water pressure is, or will be, to charge the expansion tank to.

To those who have a OWB set up with radiant floor, do you have an expansion tank? And if so, what is you water pressure?

I'm guessing about 15lbs. If I put 15lbs. of pressure in the expansion tank and that pressure is not enough, what will happen?

Ask tank manufacturer about how much pressure you can put into tank, other wise you can get VERY unhappy quickly....15psi might not be a lot...BUT....if the tank is big and not made for it....IT WILL BURSTTTTTTT!

 

[barkeatr]

yes, you would need a pressure tank. I believe the pressure reducing valve you would probably need would take care of the pressure amount...I believe the valve is set for approx 15 lbs.

You need an air scoop also...and a vent at the highest point...

Tim

 

[Windwalker7]

Today I bought a water pressure gauge, the kind you put on a faucett.

Fortunately, I have a couple boiler valves on my set up. I put the gauge on and opened the valve. The gauge starts at five pounds. the needle did not move. This reading was taken with the pump running and water heated.

When I closed off one of the ball valves, which gives the water no where to go, the pressure was 40 lbs.

Since I wont be running the radiant floor heating with this valve closed does this mean I don't need an expansion tank?

I'm confused.