Ghost flow help

oilBurnerMystery

I am having a ghost flow issue that I need help with. Multiple contractors gave different solutions and I went with one who I felt seemed most knowledgeable but am still having the issue. Hopefully this picture outlines everything you need but if any additional info is needed please let me know.

background:  I have a 70 year old home that has hot water baseboard heating (oil).  Some years back I installed a radiant floor heating system that was retro fitted into existing system.  My system is pretty inefficient so I started to evaluate areas of my system and found that when one of the 3 zones in the original system call for heat, the boiler will send hot water to that zone but the radiant floor system is also receiving hot water and heating up (when no heat is being called for).  The contractor I went with to fix this issue, installed a flo-check valve (I think that is the name) on the return line in the radiant floor section.  I just noticed that the problem is not corrected and the floor is still getting hot when not needed. The ghost flow is highlighted in purple.  Also to note, the radiant floor system has its own circulator pump that says "check valve removed".  I thought by installing that back in (if that's possible) it would correct issue. But I need expert advice here so I stop having multiple contractors here giving me different advice.  Really appreciate ur time and help!  

EdTheHeaterMan

Look here for the answer: http://media.blueridgecompany.com/documents/ZoningMadeEasy.pdf. Your answer is on page 12. But start reading about flow control valves on page 9. Then skip to page 12

EBEBRATT-Ed

you have zone valve on the rest of the system. the radiant system needs a zone valve

EdTheHeaterMan

EBEBRATT-Ed said:

you have zone valve on the rest of the system. the radiant system needs a zone valve

Not Necessarily, I had a zone valve on my radiant system. it was installed 2 years before the radiant was connected. After I connected it, I realized I needed a circ pump after the mix valve to move the water thru the floor loops. 10 years passed then a zone valve actuator failed. As a temporary fix, I swapped the radiant floor head with the defective zone head and locked the bad radiant head open on manual. A few weeks went by before I realized that I never replaced the defective head.

I have come to find that the radiant floor loops will not heat without the pump... even with the zone valve open.

So, zone valve not necessary IMO. ... YES, Ghost flow will be stopped by a zone valve, but is will also be stopped by a flow-check or the IFC in the pump. Read page 12 in "Zoning Made Easy"

Big Ed_4

Or just repipe the return of the radiant below the zone valve circulator or another low position tap of the boiler The incorrect piping of the radiant return on the low pressure side of the circulator is the ghost flow problem ...

EdTheHeaterMan

Big Ed_4 said:

Or just repipe the return of the radiant below the zone valve circulator or another low position tap of the boiler The incorrect piping of the radiant return on the low pressure side of the circulator is the ghost flow problem ...

This assumes the diagram is an accurate elevation of the piping. That may not be the case. Read page 12 of Zoning Made Easy from the link above. That is how to fix it inexpensively.

Big Ed_4

If you notice on the diagram , when the zone valve circulator turns on ,there would be a pressure drop across the radiant tees ..

EdTheHeaterMan

So you think that is enough to open that Flow Control valve? You may have a point there. I guess it depends on the pump and how many zones are open.

@Big Ed_4 believes this will solve your problem also. I believe I agree

On my system where I discontinued to use the zone valve, My circulator is pumping away from the PONPC on the supply side of the boiler. So in affect, I'm piped as @Big Ed_4 suggests

oilBurnerMystery

Big Ed_4 said:

Or just repipe the return of the radiant below the zone valve circulator or another low position tap of the boiler The incorrect piping of the radiant return on the low pressure side of the circulator is the ghost flow problem ...



Thank you for the response.  
Here is pic of actual system. Radiant floor on the right.  Blue circle is where ghost flow is. Red circle is the return line.   Just want to understand correctly....are you saying move the "feed" for the radiant system lower than the pump for the other 3 zones?  If so the only way I think that can happen is by raising the black taco pump up above those two black turn valves on left?  

oilBurnerMystery

EdTheHeaterMan said:

So you think that is enough to open that Flow Control valve? You may have a point there. I guess it depends on the pump and how many zones are open. @Big Ed_4 believes this will solve your problem also. I believe I agree On my system where I discontinued to use the zone valve, My circulator is pumping away from the PONPC on the supply side of the boiler. So in affect, I'm piped as @Big Ed_4 suggests

This was my idea I presented to the one contractor (to install the missing Flo check) but he shot that down and instead installed a flo check on that return feed from the radiant system.  I am just going to try installing it to cross that bridge. Thank you for your reply I will keep you posted if it works 

Big Ed_4

Flow checks are used for direction and over come migration . ,. Correcting the radiant return would solve your problem....

hot_rod

I would check supply in the circ, and also a spring check on the return. This should cover ghost flow in either directions