Steam boiler & spring maintenance

Snowmelt

I went to a house other day, they drained the steam boiler for summer, except for the surface rust, anything else will go wrong. I told the homeowner not to do that and I will find out why, so here I am.

Jamie Hall

Well... they didn't have to do that. However, having done it...

Step 1 is to overfill the boiler (power off) and let it sit for a bit and check for any leaks -- either outside the block (may have to take covers off) or inside, into the firebox. Check any wet returns at the same time (assuming they're not buried...)

Assuming that works, drain the boiler back down to below the low water cutout(s). Turn the thermostat up to call for heat, turn on the power. Nothing should happen (well, maybe an error message...) since the water level is low. This checks your low water cutout(s).

Assuming that works, turn the power off again, bring the boiler up to normal operating level, turn the thermostat down and turn the power on. Again, nothing should happen -- no call for heat.

Assuming that works, turn the thermostat up to call for heat. Burners should fire and off you go. Well... almost.

Keep an eye on the pressure as it starts to build steam. It may -- or may not -- get to the point where the pressure control shuts it down. This is a hard one, because in many steam systems that won't happen for a long time! If there are king valves on the header or risers (good luck with that) and on the condensate return (right...) and you're feeling brave, you can close them and bring the pressure up -- it will come up very quickly and will probably overshoot, so be ready to turn the boiler off if need be and open the header king valve first, then the return king valve.

Plan on rechecking the water level after the first few operating cycles.

EBEBRATT-Ed

Usually what could happen is any sludge in the boiler could harden and dry out plugging the low water cut off or the pigtail to the pressure control or gauge. Because the boil is mostly closed to any air this may not happen

Snowmelt

Ok I think I’m good , now what is the fluid called, it’s green looking, usually pooped in when taking the pressure relieve valve in.