Monoflow Help

van_2

I am having a problem with a monoflow loop. Some of the radiators off of the loop are not getting hot. Here is the setup:

Primary/secondary system. One zone off of this system is a monoflow loop built in the boiler room consisting of Taco 007, Flowsetter, 1" tubing and 7 sets of B&G monoflow fittings installed back to back (rings on the fitting next to each other). The output side of the monoflows go to PEX which goes to Buderus panel radiators with diverter valves. On the two panel radiators that don't heat, the diverter valves at the radiator barely get hot and the PEX return at the monoflow fitting is cold and the supply at its fitting is hot.

I have checked the Buderus diverter valves because there is an adjustment as to how much of the water into the valve goes to the panel radiator as opposed to being returned thru the valve. I have tried both the full bypass or 50% to the radiator adjustments and there is no difference, the water still does not flow in this loop. Most of the takeoffs from the monoflow fitting have ball valves so I have closed all except for one of the radiators that does not heat and that makes no difference. The radiators that don't heat are the last in the loop and one in the middle of the loop.

The system was operating fine until earlier this year when the Buderus atmospheric was replaced by a GB142. I have been bleed air from the system at the radiators but most of it is out now although you can still hear some air noise in the pipes in the boiler room. The Spirovent should take care of the rest.

The only thing different is a different antifreeze than before. Any chance this affected the pumpability of the water and the 007 is no longer up to the task? Since most of the radiators off of the monoflow loop work fine, this seems unlikely. Could the loops off of the monoflow loop that don't heat still be air bound? Could I have radiator diverter valves that got clogged or became defective? For what it is worth, B&G lists the Cv of a set of 2 fittings as 8.7. The PEX loops to the panel radiators are approx 50' to and 50' from the panel radiators.

Any ideas would be much appreciated.

Uni R_2

Hold old is 007?

As another homeowner, if I were in your shoes thinking it was my circ, I'd go get a 15-58 3-speed. I'd start on high - if cured, then keep lowering it until your heat is sporadic like yours is now and then go back to the last setting.

*edited*

BTW, those CV numbers are probably when they are closed.

EBEBRATT-Ed

Sounds like the rad's are air bound. Bleed them and see. If you dont get air then its another problem.


Ed

Uni R_2

Sounds like its running...

If he's getting heat in some rads but not in all, then to me it really sounds like there aren't enough gpms flowing through to make the venturis efficient. Unless there is a valve partly closed somewhere or some other fixable obstruction, then I'd be getting a circ quick.

Steve A_2

The higher the concetration of the glycol the harder it is to pump, Might be the 007 is no longer up to the task