Hi Everyone-  Here is the history and question

Radiant floor on Main, basement and garage.    The water feeding the floor is 105-110F and there are 3 loops coming of a main line (2") and a single pump feeding the 3 floor zones.    The main level is on 1 zone and it goes thru an Erie zone valve then ino a 3/4 in copper pipe with 4 loops (pex type lines) out into the floor.    The line coming off the main is 3/4 and then is coupled to the valve with a reducer bring it down to 1/2 ' thru the valve and then it utilizes an adapter to bring back up to 3/4 (then into the 4 loops).    Why would it have been installed like this?   I was wondering why the 3/4' line  iwould not be connected to the valve and then to the copper with the 4 loops?   The other 2 zones are connect this way too.     I was wondering if I am getting in adequate volume of hot water out into the zones.   Do I leave or should i adjust it.    The main floor is the priority zone so when it is calling for heat the basement and garage are not receiving HW

I have attached a couple of valve set-up/piping pics

Thanks for your help

are you maintaining temperature? if so you are getting adequate flow.

pics didn't make it through, but I presume it's a 1/2" valve body. why would they do that? good question. probably they had some 1/2" valve bodies laying around to use up. and it's probably adequate for small zones like you describe.

It's possible that you had a reeeaaaaaallllly anal control valve sizer on the project, and the Cv value of the 1/2" valves was the best choice for the overall flow and frictional losses of your zones. but that would be pretty unusual to find in a residential environment.

Thx for the reply. I was able to upload those pics. The 4 loops come off a 12' long 1" copper tube. If I feel the return lines, the 1 closest to the source is the warmest and the 1 nearest to the end is the coolest. The room heats up, takes a while and I am wondering if there was more hot water at that temp, would it heat quicker? Or does it really matter. Except the pump is set to the highest of 3 levels to move water. Could it be set lower, move the same or more volume and utilize less watts

Those Erie valves come with a flare fitting and all the flare fittings reduce 1 step. A 1" valve would have a fitting reduced to 3/4". It is usually fine to have a control valve one size smaller than the pipe size. It can, in some circumstances, give better flow control. Regardless, the CV of the valve includes the reduction for the flare fitting so if it is working fine, I wouldn't worry about it.

its looks like the valves are 1/2 NPT I/O's that they addapeted

Possibly designer was afraid of cavitation?

The cV is likely the same for 1/2" and 3/4" and more than adequate for most residential zones and Rob suggests. We have hundreds of homes in Minneapolis and St. Paul with 1/2" copper serving 1/2" baseboard that, because of the extra aluminum fin surface actually out-performs what is now standard 3/4" fin-tube.

The bigger the fin, pipe, zone valve, pumps and boilers; the less you have to think.