Steam boiler maintenance

Bigbri0104

Hello everyone,
My question pertains to a residential low pressure steam boiler maintenance.

At the end of the heating season, is it recommended to drain the water out of the boiler completely or not?

Thanks for help

Brian

Fred

Not recommended. That exposes the entire boiler block to air and corrosion. Some people fill their boiler up into the risers to keep the block completely under water. Others, just leave it alone. I personally change the water level up or down an inch or two at the end of the heating season so as to prevent rust through at the normal water line where air and water meet.

Bigbri0104

Thanks Fred! Submerging the the entire block underwater makes perfect sense to alleviate oxygen exposure.
Fred, have you ever came across anyone who has almost completely filled their entire system to alleviate rust through oxygen exposure? including header-pipe, main steam lines and risers, but without filling the entire radiator past the radiator vents?
I know that's a crazy thought to fill your entire system almost completely with water, but I was just curious

Jamie Hall

Don't do it. Fill the boiler to the header, perhaps, but don't fill the rest of the system. First place, consider: it's exposed to oxygen at all times except when the boiler is actually running. Second, the system isn't intended to take the pressure. Third, you can only fill it to the main vents anyway, so you gain very little.

1Matthias

Fun fact pertaining to pressure: Filling a system almost to the steam main can produce enough pressure to trip a pressuretrol set to 1.5 PSI cutout and prevent firing. Ask me how I know this.

ImYoungxD

Don't you have to burn off the fresh water to burn off the oxygen to prevent rust? If it's full to the header, wouldn't water come out of your main vent or rads?

Jamie Hall

ImYoungxD said:

Don't you have to burn off the fresh water to burn off the oxygen to prevent rust? If it's full to the header, wouldn't water come out of your main vent or rads?

Depends on the vent. If it's a Big Mouth (no float) it will come out. If it's a Gorton #2 or a Hoffman 75 or 76, which have a float it won't. However, if you leave those full of water for any prolonged period, the float may stick closed (a sharp rap will usually -- but not always -- get you back in business).

Fred

@Bigbri0104 , as has been said, don't fill past the header. I wouldn't even fill past maybe midway up the risers out of the boiler. Filling up into the radiators can wash crud back into your boiler when you lower the water level and it serves no purpose. Steel pipe, if it ever wears out (which it may occasionally) is cheap, relative to the boiler block. Once you fill it half way up the boiler riser, run the boiler long enough to bring the water to a boil to rid it of excess oxygen.

PMJ

Fresh water is the enemy. Don't add any more than you have to. Filling my steam chest and header would require more water than I add total in 10 seasons or more maybe - just to be drained back out again? I think all that new water boiled just once would do more harm than good. I just leave mine alone with the standing pilot running all summer.

bill714

If you have a tankless Coil install on the boiler it will run once in a awhile during the summer, someone told me this is good because it keeps sediment from collecting on the bottom of the block, is this true??

nicholas bonham-carter

If you have a hot water coil in the boiler, I would think it runs every day. It would be economical to add enough water to submerge the coil during the summer.
Save up for an indirect water heater attached to the boiler which will be more economical.—NBC

Bigbri0104

Thanks everyone for your help!

heatinghorse

What annual maintenance do you do? A plumber emailed me offering to do an annual maintenance including draining the entire system and flushing out the "gunk." I figure that better to let sleeping dogs lie than to disturb all the gunk which isn't currently causing a problem.

Jamie Hall

The key annual maintenance is to thoroughly clean the FIRE side of the boiler -- all passages, firebox, the works. Pretty well have to take the inspection covers off and brush industriously and then vacuum out the firebox. Takes time. Then clean and adjust the burner -- which depends a lot on the type of burner (oil vs. gas, just for starters) and requires measurement instruments to adjust -- can't do it by eye. Then make sure the low water cutoff(s) are working and the autofeeder, if you have one. Float type LWCO needs to be blown down; probe type might need to be removed and cleaned.

There is no point to draining the system and flushing the "gunk' unless you know you have a problem (slow returns).

gerry gill

heatinghorse said:

What annual maintenance do you do? A plumber emailed me offering to do an annual maintenance including draining the entire system and flushing out the "gunk." I figure that better to let sleeping dogs lie than to disturb all the gunk which isn't currently causing a problem.

thats like cooking a hot dog thru an inch of mud at the bottom of the pot.

Bigbri0104

Thanks everyone for your help!

coelcanth

some related questions:

what is the best way to clean the sludge out of the bottom of a boiler ??

i've skimmed oils off the top, but this doesn't address sediment at the bottom of the block.

my new boiler had a relatively clear sightglass during the first year of operation, but now in season two there is an inch or so of brown in the glass after it fires.

i have drain valves at the wet return and in the 90s at the equalizer and hartford loop, and one in a 2" tapping on the block itself, but these flush out with clear water pretty quick and it doesn't change the appearance of the sightglass.
i can blow down the glass too but it only stays clear until the first firing.

would it be best to remove the bushing in the 2" tapping below the waterline and add a large nipple to facilitate washing out with fresh water using a wand ?
can i just use a homemade wand (any design suggestions?) and city pressure or does one use a commercial pressure washer ?

i don't have king valves on the risers, so i can't isolate the boiler and fire to build pressure to loosen things.. which i gather might be another way to clean things out

thanks for the advice