Steam Furnace - Water Drain

palumbom

When the water in the glass gets cloudy (about every 4 weeks or so) I drain the rusty water out until it runs clear. After I drain it, the clean water automatically replaces it back (low water cutoff I think).

My question is, should I be turning off the furnace prior to draining it?

I have assumed yes, since I am also assuming that the water replacing the drained water is COLD! and COLD water added to boiling water would not be good for the furnace.

Is this thinking right? Or should I just drain it with the furnace running, as one tech told me and not worry about cold water mixing with steaming water.

Please advise.

thx!

Dave0176

Sounds like you have a float LWCO with a automatic water feeder. You can drain it while the boiler is running because your also testing the low water cutoff, the boiler should shut right down. Also the water feed should be piped off the hot water side of the hot water heater however if not, just be careful of how much cold water goes in.

Also you have a steam boiler, not a furnace, a furnace heats air.