Adding Monoflowtee

[Anthony Cavlo]

I have a Two Pipe Reverse Return Hydronic Loop system on one zone. The house has pretty even heating throughout the house except for one room with about 32 linear feet of cast iron baseboard (the longest run of baseboard). The end of the baseboard barely gets hot after a system cycle. After countless bleeding I am considering adding the first monoflow tee to this run. I am hoping to divert more hot water to this long run.

Is this idea going to work as I am hoping? Are the other radiators after this tee going to be choked off considerable?

Anthony

[krow]

I don't know what you are expecting to do with adding another monoflow T. It could simply be an air lock somewhere along the branch serving that specific rad.

we would have to know the layout of the rad and location (basement? 1st floor? 2nd floor?) , and which way the branch lines run to make a better determination

[Anthony Cavlo]

The location of this baseboard is the second floor. There are 3 bleeding nipples in this room, all of which I have bleed for 10 minutes straight. I don't think there is any air. Additionally, I have a spiralator automatic air bleeder which does not spit out any air. Everyone says its probably air but is there another way to get the air lock out?

My thoughts are that the run is too long and the water is traveling through radiators of shorter length where the path is easier. The monflow tee would push water up there even though it is not the easiest natural flow.

I don't know what you mean by which way the branch lines run.

[krow]

The rad should heat up like any other in the house.

I assume:

1) you have a circulating pump on your system
2) this rad is not a new installation and has worked fine previously
3) you have an automatic fill valve on your system

(a branch line is the pipe leading to this paricular rad starting from the main trunk or pipe.)

The bleeding nipples don't always allow you to remove the air out of the line, especially if the house has settled but the pipes have moved with the house creating a "high point" in that specific line.

This is What I have done in such cases
I found the branch line (supply and return) and placed shut off valves with a hose tap in between. Close one valve and start draining from one side. Close the second vlave and re-open the first one. This will allow the branh to be forced to "bleed".

Hopefully you have access to the branch or the existing monoflow T's so that you can isolate that one rad.

[krow]

Here is a basic idea of a possible solution

[Anthony Cavlo]

Krow, Thank you for time and patience, I am not a plumber, but a DIY guy with an engineering degree but no experience so I am not familiar with all the terms but I understand theoretical fluid dynamics and flows. And I am having problems finding a plumber who understands this as well.

My system currently has 2 pipes. See attached and here is a explanation I found:

Two Pipe Direct Return Hydronic Loop
The Two Pipe Direct Return Loop utilizes more pipe than the one pipe series loop but all radiators and baseboards receive the same temperature of water therefore it is more even heat than in all the radiators and/or baseboards than the one pipe series loop. Another advantage of two pipe direct return loop over the one pipe series loop is that it can be zoned. Zoning gives you more control over where and when you want heat and this can save you money on the cost of heating. As with many hydronic loop systems the two pipe direct return needs balancing valves. The near boiler piping may need to be modified to prevent large delta T between supply and return.


Additionally I have added an attachment. Please note my modification to the original picture. My modification depicts the fact that all the smaller radiators have a shorter path returning to the boiler therefore receive a greater flow of hot water. The longer baseboard has the greatest internal flow resistance and therefore the least amount of hot water is pumping through it.


On your assumptions.

1. It is not a new baseboard, but we have been there 5 years and the room has always been colder.
2. We do have a circulating pump.
3. We have an automatic fill valve.
4. Currently there are no monoflow tees.
5. Thanks for your suggestions on the force bleeding with a hose tap. That is interesting, However, I just want to cut the pipes once. Do you think the force bleed will work better then then adding the monoflow tee?

[krow]

Do you think the force bleed will work better then then adding the monoflow tee?

Yes, definetly. The same idea will apply to the system that you uploaded. That always get my problem rads to heat up properly.

2 isolatiion valves with a hose tap in between. They can both be on the return line or the supply line. They do not necessarily need to be on each. You will probably have better control to throttle both valves (ball valves are better to throttle with). Don't forget the hose tap between the 2 valves.

I don't really think the monoflow T will work in your application without disrupting the rest of the system

[krow]

Below is a scenario of one way the force bleeding can be achieved.

Just make sure you keep up the pressure up to at least 18 psi as you are bleeding, giving the pressure to work in your advantage.