Last leg of 3/4" heating loop reduced to 1/2"?

treecabinet3

I have a 3/4" copper hot water heating loop with baseboards ran in series. I will be cutting out the last baseboard on the loop before it returns to the boiler and installing a 1/2" toe kick heater another 10 feet away.

Can I just reduce the 3/4" line to 1/2" for the toe kick heater and then bring it back from 1/2" to 3/4" to connect to existing which then flows back to the boiler? I'm assuming this won't have an affect on pressure drop since it is the last leg of the line?

Or do I need to install it with monoflo tees off the 3/4" line , 12-18" apart?

Jamie Hall

It will increase the pressure drop in the line — since it is in the line in series (don't leave a direct connection where the old baseboard used to be. Go from the beginning of the old baseboard to the toe kick, through the toe kick, then back to where the end of the old baseboard used to be).

Don't even try to get a monoflow setup to work.

LRCCBJ

Just for a sanity check:

1. What is the total length of the 3/4" loop………….from the boiler………..all the way though the baseboards…………and back to the boiler?
2. What is the total length of the elements in the baseboards (not the shell of the baseboards)?
3. Confirm that the total length of 1/2" (including the heater) is 20'. I presume you will have 4 90 degree fittings to get to and from the heater?

None of the above needs to be very precise…………..just want to be sure a typical Taco 007 will not run out of capability……………

hot_rod

70’ is about as long as you want to run a 3/4 fin tube loop

Two tees with a balance valve will allow you to adjust how much bypasses. A basic ball valve will work

If ut is under a cabinet, make an access panel for service and adjustment

EBEBRATT-Ed

I agree with @hot_rod . Put in two 3/4 " tees in the main. The distance apart doesn't matter. Put a 3/4" ball valve between the two tees. Run 3/4 up to the toe kick as close as you can and then reduce to 1/2". Once you get the water circulating with the ball valve wide open then throttle it until you get enough heat out of the toe kick.

Don't throttle more than necessary

HomerJSmith

No, don't do it. Run 3/4" for the whole loop and use B&G Monoflo tees for the toe kick heater connection. If it is above radiation you can use one tee on the output to the toe kick. What ever you don't run the whole circuit water thru the toe kick.

I just finished a job replacing, some DA that ran, over 50' of 1/2" alum pex on a 3/4" baseboard loop thru a toe kick heater during a remodel years ago. The complaint was that it never gets above 60 deg in the living room and the boiler runs all the time. The return temp to the cast boiler was less than 130 deg.

I replace all the pex with 3/4" copper, insulated all the under floor piping, and used one Monoflo tee on the output of the toe kick. Return temps at the boiler are now above 130 deg. The length of fin tube baseboard was 56' on that loop.

It's not that you can't run a loop with more than 65' of fin tube at 180 deg output from the boiler, you can. It's just that you run out of BTUs before you get back to the boiler. But, it depend on a lot of things, environment temp delta T, for instance. So many thing to consider. Oh, well. That's my story and I'm sticking with it.