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My heating system stopped working this morning. It's an oil-fired hydronic system with 5 zones and hot water tank. This is what I have diagnosed so far:

  • The thermostats are calling for heat.
  • The relay inside of the aquastat is clicking and connecting the two sides.
  • The boiler is heating, and the gauges are showing 170F at 30psi.
  • No water is flowing through the valves. The valves are installed on the return side. I manually opened one of the valves, but still no hot water is flowing through. The pipes in/out the valve manifold are cold to the touch.
  • The recirculating pump is showing a light as in the image below. It looks purple (see image), and I recall seeing this being green in the past. Looking at the pump documentation, I see that the possible light colors are white, red, orange, and green, so I'm assuming that the purple is worn-out white. Seems that orange is normal, green is eco mode, but it's unclear from the documentation what a steady white light refers to, if indeed purple = white.
  • I can't feel the recirculating pump working, and the pipe coming from the return side is cold. But these circulators are known for being super quiet.

Question: Based on your experience, what should be my next step or diagnosis attempt? Replace the aquastat? Replace the circulator?

recirculating pump

aquastat

Cheery
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1 Answers1

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Sounds most like a bad circulator, but you could perhaps verify that power is being applied to the circulator wires (seems likely if there's a light on it.)

The sheet here (which may or may not be your exact 007e) https://www.tacocomfort.com/documents/FileLibrary/SS_007e_iSheet_102-563.pdf

Says not running and led red means rotor blocked or insufficient supply voltage. For blocked rotor it suggests an attempted unlocking procedure, (initiated by disconnecting and reconnecting the power supply) followed by (if unsuccessful) disassembly and cleaning. And if that does not work, replacement. "Purple" is not an LED color it admits to. White, green, orange and red it admits to. So it's probably (what it calls) red that you see.

Ecnerwal
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