Water Level Drops in 15-20 seconds

Pipe

Cant for the life of me figure this one out...
Replaced a 10 year old Burnham oil fired boiler with a properly sized IN4 gas fired. House is over 80 years old. Once the boiler heats up the water level drops within 20 seconds setting off the LWCO. After the system is off for 20 seconds, water level returns and boiler kicks back on again. Yes, I know your gonna say its surging, but I have treated this boiler with steam treatment - draining, flushing, etc for a year now and sure enough, I had to do it again yesterday. Once I treat the boiler, it runs fine for a month, but acts up again. Suggestions?

Fred

You can treat it and drain it all you want but until you properly skim it, you're going to have this problem from now on. There are no water conditioners, that I know of that will remove that oil. Skim it, let it run for a couple weeks and if you see the water drop like that again or bounce more than half to three quarters of an inch, skim again. It may take a few skims but you will see improvement each time. Nothing replaces skimming.

KC_Jones

Fred said:

You can treat it and drain it all you want but until you properly skim it, you're going to have this problem from now on. There are no water conditioners, that I know of that will remove that oil. Skim it, let it run for a couple weeks and if you see the water drop like that again or bounce more the half to three quarters of an inch, skim again. It may take a few skims but you will see improvement each time. Nothing replaces skimming.

Could there be bad near boiler piping causing wet steam sucking the water out? Couple that with lack of skimming and it's losing it's water quickly. He mentions this doesn't happen until it's hot, I am guessing that means once it starts steaming it drops in 20 seconds? Just another perspective, but yes I agree that skimming makes a HUGE difference.

Fred

I really doubt it. I think the oils laying on top of the water prevents the steam bubbles from breaking though that surface and consequently it pushes the water down and back into the returns/equalizer. The fact that he sees improvement when he adds a treatment and drains the boiler is a pretty good indicator that the treatment is temporarily dispersing the oil into the water, only to have it resurface as the treatment weakens. My bet is it needs a couple good skims and he'll see a big improvement and that won't cost him anything but a little time. Of course, if the near boiler piping is wrong, that will be an issue too.

Jamie Hall

I can't quite make out from your question, but has it been doing this ever since the new boiler was installed? If so, it could be serious surging from oil in or on the water, and I'm sure you checked this when you installed it, but I have to ask... was the water line of the new boiler matched -- to within a couple of inches -- to that in the old boiler? And if not, have you checked every single darn pipe out there to be sure that some pipe out there isn't wet that should be? Or is getting wet that shouldn't be?

nicholas bonham-carter

Surely there must be a higher wet return which is hiding the water, as the pressure rises, forcing water up into the returns.--NBC

Fred

I think the tell tale symptom here is the fact that he can drain it and add a chemical treatment and it runs fine for about a month. That treatment probably disperses the oils throughout the water letting the steam bubbles break through for a while. The very first thing I'd do is skim it and not put any chemicals in it. If it runs fine for another few weeks and then starts the same issue over again, skim it again. Sometimes it takes 3 or 4 skims to get all the oils out of the system. Of course he can check and make sure his wet returns are below the water line and his dry returns are above the line but again, he wouldn't get a month of good service each time he adds chemicals.

homer2101

What chemicals, if any, do you add to the boiler water before/after draining?

I am not a professional, just someone who's had to deal with a similar issue, at least in terms of symptoms. After major work, our boiler would work fine for about two weeks; then water would seemingly vanish out of the boiler during operation, and we'd get water hammer in the mains and risers. Draining would fix the problem temporarily.

We seem to have fixed it for good, at least so far, by:

(1) Skimming the boiler, in our case via the 3/4-inch pressuretrol tapping, and

(2) Adding two quarts of Oatey boiler treatment, letting the boiler run for about twelve hours, then flushing it continuously until the water from the lowest tapping ran clear.

After our plumber added the treatment chemical and the boiler came up to steam, the water in the gauge glass turned black and we got water hammer in every elbow of every main in the system. It was awesome, except for the shaking mains overhead.

KC_Jones

I do agree with the skimming. I washed mine out before it's first firing using Gerry Gill's wand method. Flushed around 100 gallons through it over 3 or 4 days. Then after I got it working I skimmed before ever steaming it. Did this for about 6 hours. After that I let it heat the house for a week then skimmed again. So far I have had zero issues no hammer no vanishing water and it's quiet. My water line still isn't as stable as I want so I know there is still more skimming needed. Wanted to add my experience with skimming for comparisons sake.

Fred

Some guys use Steam Master tablets, for several years i used Rust Raider. Both are designed to be left in the boiler after an initial cleaning but all the guys say not to follow the Steam master instructions but to use just one tablet after the cleaning. For the past two years I have resorted to using no additives in my boiler. I have both on hand but I found that my boiler water is much more stable without any additives in it. Not sure why but I do know nothing beats a good skimming a few weeks after any repairs are made to any piping on the system.

Paul_11

It does not matter how high the header is located if the risers are undersized.

A drop header won't fix that.

Water will go right up a riser 50', 60', a 100'

It does not matter.

Physics rules every time.

If the velocity of the steam is higher than the charts say it should be the velocity of the steam overcomes gravity and takes the water with it.

everyone said this already, but if the vents make noise you don't have enough vents so add more until they are quiet.

you mentioned the hissing when the boiler shuts off.
This could be air being sucked back into the air vents because you don't have fiberglass insulation on the boiler piping.

I see this a lot.

SWEI

Rhomar Hydro-Steam 9150?

Bio

Steamaster tablets are good, but will only help remove rust and rise ph level, too many tablets and the water will likely surge,
I've been using Scout and I have been very happy with it, removes any oil, increases ph, inhibits corrosion, after a few treatments it has help keep water clear, my sight glass has never been so steady even with a 11 ph reading

SWEI

9150 is a steam system cleaner, not a leave-in water treatment. I've had excellent luck with their hydronic cleaners (9250 and 9100) and several here have reported impressive results from the 9150.