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Boiler had stuck firing continuously; any things need checking?
System: oil-fired two pipe steam, weil Mclain boiler, burnham burner
While we were out of town, the thermostat failed in the open position. The cat sitter found the house at 90F, turned the thermostat to off, and verified that the boiler stopped running. The boiler would have been operating independently for up to 18 hours. I called the oil company and about 8 hours later, house temp at 75F, the technician showed up. Found that the thermostat batteries were corroded (somehow I missed replacing them this season) and changed them. Verified that the thermostat still operated the boiler and left. We got home a day later and things "seem OK".
I'm wondering what else he might/should have done? For example, I found the water in the sight glass was very high and while the system was off/cold, I drained it down to about half way.
He told the cat sitter that the plastic holder for the batteries was very brittle. I assume I ought to replace my nice old thermostat (Honeywell ChronoTherm III) that always held the room at exactly the set point. Is there anything that works as well?
Thanks for any help.