Flow Control Valve

Jim_46

I am in the middle of fine tuning the radiant floor zone 2.
I notice that if the new zone 2 needs heat it will turn on the boiler if the water in the boiler isn't hot but at this moment it is very hot and doesn't need to turn on. I have added a photo of the Armstrong Flow Control on the boiler out supply. If you feel the pipe below the flow control valve it is very hot that is why the boiler doesn't need to come on. But right now the zone 2 pump is calling for heat and is on but if you feel the large pipe after the flow control valve it is just warm. The very hot water is not getting beyond the Flow control valve unless you turn the knob on top counter clockwise to open it up for gravity flow and then it leaks out of the top knob. What is up with the flow control valve. It allows the hot water through when the main large pump is pulling heat through the main system but doesn't seem to for the smaller pump. I have teed off of this large main where the elbow used to be so the hot water can go to either zone. If the main system was just on and there is hot water in the pipe beyond the flow control valve then the new zone 1 is able to draw hot water through the 3 way mix valve to the floor. Does this type of Flow control valve even need to be on a system that has circulators?

Robert O'Connor_7

Flow control...

I'm not sure I completely understand your question. Flow control devices do just that,"Control Flow". The main circulator (not shown) is within the near boiler piping on the return, correct? If so it creates pressure on the outlet side sufficient enough to pass through the boiler and raise the weight inside the flow valve on the supply side thus inducing flow. By installing the pump after the check valve (if I'm understanding you correctly??) the pump will now have to not only overcome substantial loss through the whole system, but also through the boiler as well. I prefer the pumps (both) on the supply and individual flow valves after the pumps, I belive this is where you went wrong. Why not buy a book from this site called "Pumping Away" It will show you the proper piping schematics for most forced water systems...Robert O'Connor/NJ

Jim_46

Thanks for the reply Robert. The boiler already had the large pump on the return side from when it was a different and much older boiler. When I went to tap into the supply out on the boiler I found the easiest location was at an elbow right after this flow control valve. I removed the elbow and put in a tee. One side of the tee still goes through the old system (the radiators)and the other side now goes to the new radiant floor system. The manifold and pump for this new zone is 17' away from the boiler and the pump is on the supply pipe. I found that the pump wasn't drawing the hot water past this flow control valve. The pipe below the flow control was extremely hot but not after the flow control. So I turned the knob counter clockwise a couple of turns and then all of a sudden I could feel the radiant floor pump pulling the hot water through the control valve and through the 3 way mix valve. The floor is now getting the heated water it required. My problem is that unless I keep this knob set at this position on the control valve I can't draw the heat for the new zone and with the knob in this position water leaks out the knob on top. I wouldn't think the knob should leak when it is meant for adjustment as such. By the way I do have John Siegenthaler's Modern Hydronic Heating for residential and light commercial buildings coming in the mail as well as Carol Fey's Basic Hydronic Controls, wiring etc.

Bill Nye_2

oops

I think the easiest place to "tap in" was not the best place. Flow controls are designed to work for one zone and one zone only unless you have zone valves.

You should have tee'd in before that flow control . Then you will need another flow control valve for your new zone. If you tighten the packing nut on top the leaking should stop.

Where is the pump in relationship to your tempering valve? It may have something to do with your problem. Yes, you need flow controls with pumps. If not you would have uncontrolled heat, gravity circulation would continue after the t-stat is satisfied. Also the pump for one zone could pull heat through another zone. The biggest pump always wins.

Robert O'Connor_7

JE..

A device controls a device. Sounds like your pulling "old" (could be a new Hybonics word) water from the existing system and not heated water from the pressure vessel. You need the tee before the flow valve, and another flow valve. Confused yet? If the Flow valve is opening, its only barely opening up (my guess not at all) and that is (which I doubt) more suction than pressure. Your pulling water from the other zone. Of course your gonna get heat if you open it manually or turn the main zones pump on, but that defeats the zoning principles. I gotta hand it to you, I've never seen that before. When you get the book the light will shine!...Robert O'Connor/NJ

hr

Maybe this is why

your radiant pump is overheating (if it is) You may have a restriction on the inlet side not the downstream side we tried to troubleshoot in the other post. A drawing might be better to see how and where you tied in with that mix valve.

hot rod

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Bill Nye_2

Hot Rod

I'm thinking the pump might be air bound OR, the pump may be on the hot inlet side of the mixing valve and the valve may be closing against temperature.

Robert O'Connor_7

Mixing valve?

I/We still don't know JE's piping configuration. Mixing valves won't do a thing if its piped this way. Cap off the new tee you installed and cut in another one before the flow valve (obviously install another one for your new zone) and your done!..I did peek at a picture that was posted in another thread just now and its clearly not going to work I'm surprised nobody picked it up..Robert O'Connor/NJ

Jim_46

Thank you Gents. I have for the past two days now had the new radiant floor and room at a good room temperature and there is no air in the loops. The 3 way Conbraco mixing valve is keeping a steady temp. of 110 F for the loops and the pump seems to be kicking in when the second Zone T-stat calls for it and it is wired into the Aquastat and turns on the boiler when it needs to. But yes I agree that the way I temporarily have the Flow control on the boiler turned back (gravity flowing)to allow heat for the new zone is only that... temporary. Both zones will be pulling from each other etc. I will send a drawing in a bit of my mix valve set up etc. But right now I need to put a tee on the vertical pipe coming out of the boiler and then put the 1 1/4" Armstrong Flo Control back on for the old zone because it is sized for it and then put another Flo control valve for the new zone. The old zone (zone 1) has steel 1 1/4" piping but the new zone uses 3/4" copper. Can anyone recommend a Flo Control valve for this new 3/4" piping? The Tee will be steel 1/14" but I don't really want to use the same size flow control for this smaller zone so I can down size with a brass fitting and then put in a smaller Flo Control if you can advise one for me. Thanks again.

Jim_46

Here is a quick and very crude schematics of my zone 2 with the mix valve and checks etc. It also shows how I will change the flo control to 2 flo controls. Any ideas for what Flo cintrol to buy for the second 3/4" zone 2??