2 pipe direct return (hydronic)

jbeck

Would like some help troubleshooting my heating system.

• Hydronic, 2 pipe direct return.
  
• 100 years old, was previously a gravity system with big cast iron supply pipes.
  
• Now has a B&G circulator on the return side.
  
• Building is 2 floors with 2 supply / return loops. Each loop spans the front or back half of the building.
  
• Each loops starts as a long horizontal branch (3" pipes) that eventually travel up 1st and then up to 2nd floor.
  
• 3/4" T's split off the main branch to each cast iron radiator
  
• Radiators have been bled.
  

Problem
1st floor radiators are 110F surface temp (Room temperature 68F)
2nd floor radiators are 140F surface temp (Room temperature 72F)


In a 2 pipe direct return + circulator, wouldn't the 1st floor rads get the most flow?

Why are my 1st FL rads not getting hot as upstairs? The problem may have started when I installed TRV valves on the 1st floor. I installed them to control 1st floor temperature. the 2nd floor radiators.

Note, the 3/4" supply / return pipe coming off the radiators are both hot.

BTW, I installed Honeywell V110 valves. The valves are not stuck. I also unscrewed the control to test if they were defective, but the rads don't get any hotter.

https://s3.amazonaws.com/s3.supplyhouse.com/product_files/V110E1012-Submittal Sheet.pdf

jbeck

Any chance the Honeywell V110 TRVs were installed in the wrong direction? Would this cause underheating?

jbeck

I confirmed that the TRV was installed backwards. What's lame is that the original plumber won't fix it without charging me

JohnNY

jbeck said:

I confirmed that the TRV was installed backwards. What's lame is that the original plumber won't fix it without charging me

Did the plumber install them or did you? Who provided the valves?

jbeck

I bought the valves
The plumber installed them. Backwards.

To be somewhat fair, he simply replaced the original valves with these TRVs. And some of the original valves were on the RETURN side. He obviously never checked which pipe is which.

EBEBRATT-Ed

the trvs are adding restriction to the first floor. TRVs can't give you more heat. They will only prevent over heating. Converting a gravity system to forced can be problematic and will result in some trial and error. Hopefully when the valves are turned around it will work

jbeck

Original Plumber refused to fix the work himself, so I personally replaced the backwards TRV with regular radiator valves. Also left him a valid review on Angieslist/Google/etc. Suffered with underheating for 2 years before finally self-diagnosing the problem. Other plumbers (including 1 on this board's FIND A CONTRACTOR) could not diagnose it.

Of course, their lazy take was "your piping is all wrong" (which it is, but it wasn't fully responsible for the cold rads).

Anyways, parding my venting. It's been a long 2 years.

With regular valves, radiator surface temps are now 140F. Previously 110F. (Aquastat high limit is set to 175)