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basscop5000 06-30-2010 11:42 AM

Oil furnace trouble after running dry
Hi, my oil burning furnace (for both baseboard and supply) had run out of fuel 2 days ago, we got a delivery yesterday, so I went to fire it up again. I was told I would only have to bleed the fuel line if the boiler didn't fire, but it went first shot. I'm not a pro on boilers by any means, but I believe I've lost pressure on the expansion tank side (also the line that runs to baseboard heating).

This is on a Thermo Dynamics model S-125, ~10yrs old.

As soon as it fired back up, the hose nozzle on the same pipe as my T/P RV (about 1" apart on the pipe, 90 degrees difference, valve is at the end of the straight pipe) started releasing all the water going through that side. I can stop the hot water dump by turning off the baseboard/expansion tank side, but that doesn't get me a fully functional boiler. Currently we have full running hot water, and though the heat isn't necessary in the summer, I'd rather not wait to get this working properly again.

A few questions here:
- Is that nozzle in the rear the release for the valve, or would it come out through the outlet blocked by the valve?
- Do I need to drain/repressurize my expansion tank, and if so... how?

Any advice is more than welcome, and I can provide pictures or more information for clarity.

Thanks in advance.

silentdub 06-30-2010 02:09 PM

I was going to say you need to bleed the line, I don't know anything about boilers, but ensure that the system doesn't just fire and go out, make sure it stays lit, otherwise, bleed the air from the oil feed.

basscop5000 06-30-2010 02:41 PM

As far as bleeding, it doesn't seem to be an issue. The boiler only cuts off once it reaches the set temperature, which seems to be at least fairly accurate on the gague. It's not a problem with heating, but the expansion tank/heating side flushes any time I open it up... supply is still hot, and it seems to fire up properly with low pressure in the supply line.

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