HW Heat Problem

I had the furnace replaced (it is in the basement) in a two unit rental last Spring. On the first floor, heat is provided by six radiators connected by single diverter tees to a copper tubing monoflo-design system. Now that heating season is here, the first floor radiators do not seem to get very hot. (Heat for the second floor is provided by the same furnace but the second floor radiators are connected by regular tees to separate supply and return lines, and the second floor system seems to operate ok.)

The company that installed the furnace asked me to trace and label all the radiator risers to make their troubleshooting job easier. (I couldn't fault them for the request because the basement ceiling is a plumbing mess.) I have done that and found that as I follow the monoflo main in the direction of water flow, for the first three radiators the diverter valves are installed on the second riser (the return?) and for the last three the diverter valves are installed on the first riser (the supply?). The red band on each diverter valve is between the risers of the radiator it serves, so they are installed correctly, but three are installed on the return side of the radiator and three are installed on the supply side. Is this typical, and more importantly, could this be part of the problem?

I don't know if this helps, but when I bled the radiators recently, no air came out and the stream of water was not very strong at all. Thanks in advance!

your first floor radiators are air bound (locked). You have water coming up one side of the radiator but the otherside of the convector is resisting purging. Yes it would be nice that you have all of the tees facing the right way in regards to the pump and on the feed side or better yet have monoflow tees on both sides of the convector. Your not the only one with problems like this. I get customers telling me that there wasn't a problem before but the system was designed poorly and nearly makes it impossible to purge out all of the air yet they don't want to spend the money to correct it.

Generally what happens when filling the system and bleeding quickly you get the air stuck on one side of the radiator legs and it won't come out. The only thing I could suggest is to drain all the water back out of the system and refill the system VERY SLOWLY with the vents open. You will need several people to watch each vent and be ready to close them up.

There are many special methods for trying to resolve this but none that I can think of at this moment that a novice should try. Just curious. Where is the guy that installed it last spring? Doesn't he guarantee his work or did you both agree that there may be a problem with the way the system had originally been installed and you were going to be responsible for the consequences.

Monoflow Heat Problem

Jeff, Thanks for the reply. The company that installed the system is very reputable and is coming back to check out the problem early next week, after I've labled all the radiator risers and mains. If the problem is with the work they did I am sure they will make it right. They installed a new furnace and associated mechanicals on a 40+ year old system that was originally a single system, was subsequently divided into two separate zones and there is evidence of other modifications as well. For this reason I thought it was reasonable for them to ask me to label everything to make the troubleshooting easier. I'll mention your point about air in the system to them. I'm not planning on doing any of this work myself, I was just curious why the diverter valves would be installed with three on the supply side and three on the return side of the six radiators. Thanks again!