1/2" hydronic heater on 3/4" loop

[asdf43]

Hello all! I recently ordered a 4' baseboard hydronic heater. I didn't even contemplate that it could use a non 3/4" element but when I went to install it I found that it did indeed have a 1/2" element. I contacted the company and they do not make a 3/4" element that will fit in this heater. So that either leaves me returning it and finding another one or finding another way to plumb it in without restricting the water flow through the loop.

I would like to keep the heater its a pretty high end unit. So what I was thinking is where my 3/4" pipes come up through the floor, what if instead of elbowing into the element as usual I get a couple of 3/4, 1/2, 1/2 tee connectors. Use those to connect the element to the loop and then run a second 1/2" line across the top of the element. That way my 3/4 loop will basically just split into two parallel 1/2" lines one being the heating element and then combine back up to 3/4 on the other side of the heater.

Does that make sense? Would it be a reasonable solution to this issue or should I just pick up a standard 3/4" heater that I know is going to get all rusty and cruddy in a few years?

Thanks for the advice in advance!

PS, a little calculating shows me that two 1/2 inch pipes have a total cross sectional area of 0.393 inches while a single 3/4 inch pipe has a cross sectional area of 0.442" I'm not sure that's a significant difference?

 

[Jadnashua]

The water will flow through the easier path. To keep things even, you may need to throttle the flow in the bypass pipe so that some will flow through the (probably) more restrictive unit. Not an ideal situation.

 

[Sponsor]

 

[asdf43]

I was assuming that since a 1/2" pipe has slightly less than half the cross sectional area of a 3/4" pipe that the two pipes together would split the flow pretty evenly with only very slight restriction compared to a single 3/4" pipe. That would mean that only half the hot water is going through the pipe with fins on it... Not sure if that's an issue. Shouldn't be though as both pipes would have the same temperature water in them. Restricting the bypass line any would continue to restrict the whole loop though and that could cause the EOL baseboards to get cooler, no?

 

[Reach4]

If you want less restriction, you could open the valve more. If the bypass turned out to be undesirable, you could close the valve. Otherwise you would keep it at an intermediate setting.

I would not presume that your radiator will provide as little resistance as a pipe of the same length. I don't know. I suspect you should not be confident that you do. We can agree that having the valve would not hurt and it may be useful or important.