jrv8984 wrote:Anyway. Can regular ball valves be used When talking about balancing/flow control valves. How do you regulate the flow without some kind of gauge?
And the split tee method is used for 2 radiators in a room, how would you plumb it with 3 radiators, or an odd # of radiators in multiple rooms?
You should use brass or bronze HOT WATER full port ball valves. They do not have to be lead free, though that may be all you find these days? Teflon is fine, which usually means up to 400F. The system is low pressure (operates typically max about 30psi), so no need for super expensive, high pressure ratings.
I'm not an expert on ball valves or plumbing, but some here are. Maybe they can offer additional info?
As for balancing, obviously gauges are best, but I did mine by ear and touch. One side is cooler than the other, then as you start to close that side, the neglected side gets warmer. Note that point. Go until the previous side gets neglected (cooler, less flow that you can feel if you hold the pipes), note that point. I usually set it in between those points, biased just a bit to the weaker side.
I also prefer to have my ball valves on the return side of the loop. I don't know if that is right or not, but it makes sense to me. Any turbulence or noise is then down in the basement rather than amplified by the radiators/baseboard.
For Split tees, you can split up the zone anywhere you want, with any number of radiants. Each "half" is simply connected in series. It is the initial supply and final return of the zone that is split out of/into a tee.
As an example, I run a 1" supply line to the far side of the living room along the basement ceiling (happens to be perpendicular to the floor joists). Just before it goes through the floor I put a 90deg to turn it vertical with a short stub of pipe, then a 3/4" x 3/4" x 1" Tee is tucked up inside the joists and oriented so the 3/4" ends are parallel with the joists.
I then added the longest pieces of 3/4" copper pipe I could still maneuver into the joist with wires and such in there. One side runs to the East side and one runs to the West side of the living room, each turns up through the floor to meet the end of the first baseboard on that side. (actually the West side goes almost straight up into the North wall's baseboard, but we'll call it the West loop anyways
The baseboard sections are daisy chained on each side, the output of one connected to the input of the next. The return of each then comes back to the basement the same way, but just before another 3/4" x 3/4" x 1" tee, they each get a 1" ball valve for balancing. If you KNOW one side will be weaker than the other, you can maybe get away with a ball valve on just the heavy side, but there are other benefits to having valves, such as closing one side to purge air during initial fill.
The return side then has a shorter run of 1" pipe to the return side of the primary loop. I deliberately chose to have the longer runs be the supply sides.
Radiants' BTU output varies significantly for as little as 10F difference in water temp. One decent size cast iron radiator can easily drop it that much. Putting 2 or 3 in a row can end up with a cooler, or even a cold radiator at the end of its series row. Split tees can help significantly by providing full temp supply water at two points: at the beginning of each of two halves.