hot returns on 2 zones that are off

Big Ed

If I had a chance to look at your system I could spot the piping error . But to correct the problem you can install a spring check or flow valve on the problem return.....

jim P._2

Why are the return pipes on two of my zones getting hot when the third pump is on? I have 3 zones and when one calls for heat the two other 2 zones get hot on the return side. It seems the hot water gravitates back into the returns and it reaches the cast iron radiators on the other 2 zones. The radiators dont get really hot but warm to the touch. The return pipes get very hot. The hot water does not go past the flow checks on the supply side but when it comes back to the return manifold it goes to the other return lines and winds up reaching the rads "backwards". I have a 1 1/4 inch manifold with three 3/4 supply pipes and 3 Taco 07 with flo-checks. On the return manifold the pipe sizes are the same. This is a loop system. Why is this happening? What can i do to stop this? Thanks Jim

jim P._2

ghost heat

Ed I checked the piping and i dont see anything wrong. I have two headers, one supply and one return. 3 zones with pumps and flow checks above them. Number one supply goes to #1 return and the same for two and three. I dont have any ghosting above the flow checks on the supply, just on the returns. The return pipes get very hot for at least 30 feet going "backwards" on the loop. I will put a spring check on the returns when the season is over but I would like to know if this is normal or if something is wrong.

hydronicsmike

Like Ed, I am assuming Ghost Flow...

Have seen ghost and reverse flow even through one pipe, your return in this case. How to stop it if piped correctly? Maybe have the Check Valve in the Returns. See what others have to say about this as well.

Hope this helps.

Mike

Big Ed

Trace the Flow

Ghost Flow problems tend to be a miss placed tee. Like in Dan's writings "What ever goes into a tee comes out off a tee". You mentioned Radiators ? What type system ? Is the problem loop a parallel type zone? They use alot of tees.

I see calls for Ghost Flows after a new "Pumping Away" installs where a installer plugs return pipes into a return drop haphazardly . All the returns don't have to flow back to the boiler...Before we had the flow valve on the supply and the circulator on the return you had to connect it right. The key is connect all the returns from a zone to a single pipe , then connect to the return drop...

You can trace the warm water around the loop to find the problem or add a check valve for a no brainer ...