Slight drip from pressure relief

Mark_24

Here's what I have: Weil's Mclain 368 top flute furnace with Beckett AFG oil burner, hot water baseboards.
I suspect it's getting too hot. I replaced the triple aquastat relay last winter for other reasons (I thought it wasn't accurate, but ended up having a bad T-stat wire untimately). I have the low switch set for 170 F, 25 degree swing so it should shut off at 195 F, and a 210 high emergency cutoff. I noticed last night that the temperature guage is reading 220 before it cuts off, and I swear I hear water steaming inside for a few seconds after shut off. Do those things get out of calibration and need readjusting? Or could it be soemthing else? Possible bad temp guage and I'm barking up the wrong tree? The pressure hovers around 15psi. If it gets too hot, would a drop or two of water leak out of the relief after an hour or so? Any of you pros have any ideas before I lower the temp settings and see what happens?

Al Letellier

dripping relief

You have the high limit set too high. The relief valve will discharge on pressure only. The high and low limits should be 20* apart. At 210, you're just shy of steam if the pressure was zero, so be careful. Reset controls to 170/190 or 180/200. If the relief continues to drip, get it changed. Trust the aquastat settings more than the temp gauge. The 68 was a great little boiler, but can't say the same for the gauges that came with them. Use a pressure gauge attached to a hose adapter and screw onto a purge or drain valve to verify pressure reading.

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