Should a steam boiler be drained in the spring or left wet

ttekushan_2

of this method:

Fill to the top, and fire just to the onset of boiling to drive off oxygen, and shut it down competely, leaving it filled to the top to protect the iron for the summer.

tom_74

I have a steam boiler. Should it be drained & left dry for the summer or left wet

ed wallace

steam boiler

I have never heard of anyone draining a steam boiler and leaving it dry all summer seems to me draining it would allow the cast iron to start to rust away of course im not the brightest bulb on the market

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Patrick Linhardt, \"Linhardt's Field Guide to Ste

no

Hi Ed,

I'm not sure how bright your bulb is either, nor do I want to know, however you have the right answer.

Do not drain the boiler "for the summer". To refill it would add fresh water to the system. The idea is to keep fresh water make-up to a cast iron steam boiler to a minimum, since it contains all that stuff that is bad for boilers.

If the sediment in the bottom of the boiler is especially thick and needs to be flushed out, then that is a good reason to drain and flush the boiler. But to drain the boiler just because it is the off season, then that is not a good reason.

Best regards, Pat

Tony Conner_2

If It...

... was mine, I'd drain it, flush it out with a hose, then leave it empty & open for the summer. If you leave a steam boiler with water in it, the upper layer of water can absorb oxygen from the air, and cause pitting at the water line. You can deal with this by adding an oxygen scavenger like sulfite, and firing the boiler up to temperature once a week or so, but this routinely gets neglected after a few weeks.

When it comes time to refill the boiler, fire it soon after filling. That will drive off the dissolved oxygen in the fill water.

Dave F_3

I really dont know much about light bulbs , but if you are not using your boiler for domestic hot water , drain it , and take the smoke pipe down , open it up as much as possible , clean outs etc . Let the air into it .You will get a small amount of surface rust , but this is better then Rot Dave F

gerry gill

yup, its what Dunkirk

boiler company says to do..

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midway

Here's what our service man has said about summer setup ... we no longer use the hot water part of the Burham V 74 so he has set the furnace to keep the water in the boiler around 112 degrees, says this will keep the joints from opening up?? Whether this is true or not thats the way he has it set, is it worth it ?? What are your thoughts on this?

Boilerpro_5

Me too....

I've also heard on up from there. Fill the boiler until the riser begins to get filled. This makes sense to me since there is alot less surface area to absorb air and pitting here can be dealt with by replacing pipe. Also you won't be combining the action of summertime pitting and winter scrubbing of the iron at the water line to have the section wear thin faster.

Boilerpro

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Christian Egli_2

We meet up with forced air again - in a pyramid, no less

In spite of the many ill some people say of the content of a steam system, I find there really isn't anything wrong with boiled water, what is bad - real bad - is all the noxious air we expect our boilers to live with.

Fresh air is bad. Fresh water is just as bad.

Flushing the boiler and filling it with new water just before sending it off for summer vacation would be a real bad idea unless you make sure you treat the water with all the anti-corrosion and oxygen scavenging additives.

Draining sounds good but it is only as good as how well you can dry the innards of your boiler. If there remains a puddle, then your efforts are no good because the inside-the-boiler air will contain the perfect moisture for allowing corrosive oxygen to chew away at your iron.

For acceptable dry summer storage, you need to be able to insert a cartridge of dessicant inside the boiler and you have to be able to open at least several holes (hand holes and such). Not easy to do for just a 6 months break, but a must for anything longer.

I've also heard about dangling a light bulb (a bright one...) into the dried water cavity and keeping the light on for a little warmth. Maybe? Seems tedious.

Muck dries up too. What was easy to handle mud during the heating season might become a calcified clog once dry.

So, the lazy way of just doing nothing until the heating season starts again isn't the worse one. Isn't that cool?

Some easy improvements to help the boiler: go for sequestration.

Air is the bad stuff you want to keep away. It comes back in into the system via the air vents. The radiators and the piping survive OK because they dry themselves good enough on cool off.

Removing the air space in the boiler by filling it with water is good, but you either have to boil this water or add chemicals to it.

And to keep the air from going into the boiler in the first place, just shut all valves to it. Label them as shut so that you won't forget to open them again. Sadly, many boilers don't have a king valve.

Adding chemicals for the summer is a very good idea, as Tony mentioned.

Next,

Keeping the boiler set at any below boiling point temperature for the whole summer is an expensive waste of energy. It might have some benefit for keeping dissolved oxygen out (not real sure) but the really bad thing it does is to cause you to add quite a bit of fresh water throughout the summer. With the slight simmer, you'll still be evaporating lots of water, and it will be free to leave the system since you don't build enough pressure and heat to activate the steam trapping mechanisms in your air vents. And you'll add fresh water through the automatic feeder... fresh... not too good an idea.

The same problem is true with a domestic water coil summer boiler operation. I find domestic water is best left to it's own appliance.

We don't want either fresh water or fresh air to foul up our lives, do we?

Anecdotal evidence.

We once had a 1 1/2 return that had been abandoned because of a change of plan. This pipe had had 30+ years of service as a dry return before it was capped off at both ends. After that, it remained half full of condensate for the next 20 years. When I opened up this pipe like a common tomb raider breaking into the pharaoh's secret crypt, my big surprise was how well the pipe kept up. I was surprised to even find water in there. A simple flush and the return was plenty good enough for reuse. None of the threaded fittings were even hard to unscrew. I've worked with pipes that were in open humid environments for less time than my 1 1/2 return that were simply impossible to revive, but these weren't on a steam system... aaah.

My conclusion is that keeping things sealed off from air is a perfectly acceptable method of preservation, whether condensate is present or not.

Of course, breaking into this sealed off pipe came with a inescapable curse: steam went through my brain

Hey, I think it's time to stop and get a breath of fresh air.

May our boilers have a nice summer vacation.

Bill Jirik,

long term storage

I like to see cast iron boilers stored (30 days or longer) either full to the header and warmed occasionally to drive off disolved oxygen or completely drained, if left at the normal off cycle water level the high PH and disolved oxygen can really start to do some damage depending on your water quality, by filling up to the header you will know if there are any leaks above the normal operating water level and with one pipe steam gravity return systems you will riase the level in the wet returns, a lot of corrosion ocours around the normal water line, by raising the water level you redirect a lot of that corrosion, easier to replace a steel nipple on the header then a corroded through cast iron section

frank_25

My father (RIP) was telling his customers the exact thing back in the 60's.

appo

educ

My grandfather had his McClain 400,000 BTU steam boiler for 10 years and the low cast iron section rotted out. My grand father religiously flushed the boiler out every spring and left water in the boiler through out the summer.



I believe the water needs to be flushed out, and the boiler heated for three minutes while empty with the drain valve open to allow evaporation of excess moisture. The drain valve should be left open throughout the summer.



Water is the cause of all rust!