Taco valve failure modes

Joe Mattiello

Tom Macintosh

Taco 570 series valve problem.

I have a zone with no heat. The system has 3 zones with indentical controls. The taco 571 valves are operated by a Taco ZVC 404 controller. The system has worked without a problem for the last 3 years since I installed it. The symptoms are as follows: Zone 3 is showing a yellow LED, but no red LED. The themostat is closed and the Taco valve head is hot to the touch. The down stream pipe is cold, showing that valve colsed indication on the controller is true. (No red LED) Operating the manual level with the thermostat closed starts the circulator and provides heat and a red LED. Is this a valve head problem or do I need to replace the entire valve?

Timco

If you can manually turn the valve open, sounds like the head. Use a voltage tester and vfy that you have proper voltage first. If so, head it is...

Tim

Tom Macintosh

The fact that I can manually open the valve makes me think it's a problem with the valve body. Operating the lever closes the valve position switch and the circulator starts. I think these valves work like one of those Butterball turkey pop-up timers. The head heats up and opens the valve. I'm getting heat, but no valve opening. I really don't feel like getting out the torch.

Ray Landry_2

The head can be removed/replaced without changing the valve body/soldering just turn it 1/4 turn to the left with the power off

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Ted_9

zone head

That's what it sounds like to me.

Massachusetts

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Joe Mattiello

The Taco 570 series does have replacement actuator, and valve seat assembly available. Taco offers a very generous 3 year warranty on the actuator, and 5 years on the valve seat assembly. The actuator is easily replaced with a quarter turn, while the valve will have to be isolated for replace the seat assembly. For your reference I attached a trouble shooting guide to help trouble shoot your system. After reading your inquiry, it became apparent you have an actuator failure that is hindering the opening of the valve. If the valve end switch does not close the red LED light will not illuminate, and the main end switch will not close. FYI, using the manual lever to open the valve does not guaranty the valve end switch to fire the boiler will close. If you apply 24 volts to terminals 1, and 2 the valve will open after approximately 1.5 minutes, closing the end switch between terminals 2, and 3 to fire the boiler

Joe Mattiello
Technical Support Engineer
Tel. 401-942-8000 X 484
Fax. 401-942-2360
1160 Cranston St
Cranston, RI 02920
joemat@taco-hvac.com