taco radiant mixing block

rick in alaska_2

I have just finished installing my first RMB. I started up the system and noticed that the supply temp to the system did not want to come up as quickly as I expected. I put my hand on the return line from the slab and burned my hand. I checked the supply pipe and found it to be mostly cold. After some troubleshooting, I determined that the supply temp from the mixing block was coming from the port marked as the return. Since I had the sensor on the wrong "supply" line, the control was trying to raise that temperature.
To make a long story short, I put the sensor on the "system return" and the temps are running normal now. Except that the supply from the mixing block is coming out the wrong port of the mixing block.
I have double checked taco's paperwork, drawings,and written instructions and find my piping to be right. Also, the mixing block is marked as supply and return.
Any thoughts as to why or how the flow can run like this?
Time to turn in, so I'll check back in the morning.
Rick in Alaska

Weezbo

hmmmm..... *~;)

maybe i can help.....did you turn the block on manual for a while to bring the slab up to heat?pumping away?what control are you using on the boiler? do you have globe valve or a ball valve on the return to the boiler?supply ?i have about six of them rolling right now.do you have temp gauges on the supply and return?e-mail me a picture. of the lash up.and associated piping .

Rick in Alaska_3

fixed it

I went back and did a little more testing after getting some sleep and found the molex plug for the system pump on the controller was not making a clean contact. I guess that's one more for the molex plug problems. Apparently with the system pump down, the injection pump will cycle some hot water through the system out the return line. Thanks for the help.
Rick in Alaska

Joe Mattiello

RMB mixing block

Glad to hear you corrected the problem. Please feel free to call me with any additional questions or concerns.

Taco, Inc.
Joe Mattiello
Technical Service Technician
joemat@taco-hvac.com
401-942-8000 X 484
www.taco-hvac.com

Ted_9

These are nice little units. Ive done our second RMB-1.

PATRIOT HEATING & COOLING, INC.

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