splitting 1 zone into 2 with zone valves - uneven heat

BigMak

I split 1 zone into 2, and the heat is uneven. I was working previously. I had repiped it with a similar configuration using just Tee's. Now, not so much. I have it as the last port on a 3 zone speed header, (probably should have made it the first, but the piping lined up to good to pass up). then branching off to a tee, and on the return a similar setup.

I'm wondering should i have used a diverter Tee instead. I need to add 2 more valves for each branch after first tee, to be able to purge. I did purge at baseboard, but it still seems to be lacking. wondering if i should partially shut the first 2 zones on header to allow greater pressure for the 3rd.

the top branch is getting more heat than the bottom. the bottom has more elbows than the top, could also be another reason, more resistance.
see pics:




thoughts?

STEVEusaPA

You should've added a way to balance the zones. Your pex changed the dynamic of the zones. You probably did yourself a dis service by taking an oversized oil boiler and braking it into multiple zones.
Trying to reduce flow with ball valves is equally ridiculous.
Besides all that, the rest of it looks like it's begging for a sawzall-ectomy.

BigMak

Yes, that's what I'm trying to do, is balance the zones. so, suggestion on that?
it had 4 zones, for the last 10 yrs, and it was balanced, although had to bleed at BB. I change up the config. it really looks a lot cleaner now.
what do you think the BTUs on this is?

Believe me, I've been waiting to preform a Saw-Zall-ectomy on this thing, but its not an option at this time.

SuperTech

Is that seriously piped in all 3/4"? I highly doubt you are flowing enough water for the BTU output of the entire boiler. 3/4" PEX has a smaller inside diameter than 3/4" copper so you are losing capacity that way as well.  

Is the rest of the house piped with monoflow or diverter tees? Do you have cast iron baseboard or radiators? Is this a split loop system? If yes to any of the above questions than you probably screwed up the balance and flow to all the emitters. 

Ironman

Pumping into the bull of a Tee is a big hydronic no no as well as being against code. 

As others have mentioned, you’ve probably thrown the system out of balance. Hydronic piping requires proper design; it’s not just connecting pipes. Without knowing  the particulars of the rest of the system, giving accurate advice is difficult, if not impossible.

Is that O2 barrier PEX that you used?

BigMak

@Supertech: The whole system is 3/4" pex and copper mixed, with the exception of 3’ on the return off the boiler. It’s a single series loop with baseboard, some 30 & some 80 finned. All pex it O2 barrier. (no monoflow or diverter tees).

@ironman: I can rotate the tee and add in an elbow. My concern is that it may by pass the tee and most of the flow will got to the to the elbow, (taking the path of least resistance). I didn’t know it wasn’t code. I do want to do things to code. So if I rotate and add elbow, will the flow be equal, how do I regulate flow?

All pex it O2 barrier. What additional information would help in evaluating? I don't have any info on the boiler itself, other than its 75yrs old, an Ideal #7 by American Radiator Company. It looks like it was/is a steam boiler, it has 2 supplies and 2 returns. I have a becket burner, with a 1.25gph 80*A nozzle tip. Don't know what the BTUs would be. I would guess its over 150KBTUs. All 3 circulators are on return side, (originally installed), 2 are Taco 007-05, one is black instead of green, but it looks like a 007-05.

mattmia2

Is there a single flow check on the supply before the zones connect to the manifold?

What is going on with both zone valves and multiple circulators?

BigMak

yes. directly connected,.

Zone valves functioning normal. 1 circ for the 2 zones. Other 2 circs are separate zones, no split.

I'm going to take ironman's advise and rotate tee. But wouldn't the first branch get more water then the second?

Ironman

You should connect the return Tee in the opposite manner of the supply; in other words, reverse return.

Water will still take the path of least resistance, so if you have more resistance in one loop than the other, that’s gonna be its preferred path.

You may also be air bound in one or both loops since there’s no means of isolating one from the other before the return Tee.

BigMak

Here's a pic of the return side. Is what you mean by reversing the return to make to make supply: 3A connect to Tee; return: connect to elbow. and visa-versa for 3B?

So there should 2 more valves on this return, one for each 3A & 3B? the single valve below drain valve wont work for both zones? would it siphon water from the other line as it drains pass? Or wouldn't the zone valves function as a valve for purging?

Paul Pollets

This system is in need of a serious repipe. Not to mention a boiler replacement. I'd be piping the feeders in 1", not 3/4"; don't dead head the tees; pipe the supply having the pump push away from the expansion tank and follow the diagrams from "Pumping Away" or in John Siegenthalers articles or books. The wiring leaves everything to be desired and you can't put a band aid on what needs stiches.

Ironman

I’m sorry but your pics are somewhat confusing to me. I thought the zone split into two loops.

Also: never use a flow check when you have zone valves. Doing so isolates part of the system from the expansion tank when both are closed.

I realize that you’re trying to fix what you’ve got, but I have to agree with others that it’s time for a new boiler with correct piping.

KC_Jones

Paul Pollets said:

This system is in need of a serious repipe.

This is the repipe

https://forum.heatinghelp.com/discussion/185110/repiping-an-old-boiler

BigMak

@Ironman yes, the 3rd supply line 3a&3b is the split. B has the return tee, so i'll supply with elbow (yet to be installed, still deadheading tee). and visa versa for A. blue is return, orange supply. is that what you meant by "Tee in the opposite manner of the supply; in other words, reverse return."?

mattmia2

Is the flow check installed in the circulator in the other zones that are zoned by circulator? That flow check by the boiler is in the wrong place to keep flow from a circulator in one zone from causing ghost flow in another zone where the circulator is off.

If you brought it 1" or bigger up in to the tee where you split the zone there would be more flow to divide between the 2 and it would inherently be better balanced although the piping of the 2 inevitably isn't of equal resistance. You can balance with a ball valve but the response isn't linear. A globe valve would give you more precise control.