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?