New boiler nightmare

jjheat

I replaced an old Burnham gas fired steam boiler with a new In-10 for a 3 story 1 pipe steam system.
The new 3" header is 32" above the water line and i used 2 2" supplies from the boiler to the header. The hartford loop and equalizer line is 2" with an 1 1/2" wet return line. I dont have pics of it but the problem is that when the boiler gets hot and making steam, the mains get hot then the water level drops and stays down and kicks off on low water. Water level is not bouncing at all just going down when getting pressure built up and cycling so no steam is making it upstairs to level 2 & 3 of the house. I skimmed boiler 3 times for 2-3 hours each time. Any suggestions?

BobC

Are any of the returns tied together close to or above the waterline? Assuming the water eventually returns on it's own, have you checked for partially blocked returns?

Bob

jjheat

1 return is 1" from short side and 1 1/2" from long side of house. Returns are twinned together on the floor and come across and up into hartford loop tee. I flushed returns before removing old boiler.

Abracadabra

1 - Need pics of near boiler piping.
2 - might need to skim more?
3 - Was attached EDR calculated and used when selecting new boiler?
4 - Does water line return to normal after boiler cycles off or does boiler flood?

jjheat

No pics available right now. The 2 supply pipes come out of the boiler and into the side of the header at 32" above the water line and both supply lines are tied in before the 2- 2" steam mains then reduced with a 3x2 90 to the equalizer line.

Fred

It is quite possible it just needs a lot more skimming. AQre you skimming it very slowly and with the water in the boiler hot? Sometimes it takes several skims. The more piping that was replaced, along with the boiler replacement, the more skimming required. What is the Pressuretrol set at Cut-in should be .5PSI and Differential at 1PSI for a cut-out of 1.5PSI. When I first moved into my house, the boiler water would drop to about a half inch from the bottom of the sight glass. Skimming, multiple times, resolved that problem.

nicholas bonham-carter

Are there any horizontal pipes just above the waterline-even quite far away?
if so then the pressure raising the water in the returns will try to fill up that pipe, until the water is gone from the boiler. as the steam condenses, all the water will come back, until the burner fires again, for the next cycle.--NBC

Abracadabra

Abracadabra said:

1 - Need pics of near boiler piping.
2 - might need to skim more?
3 - Was attached EDR calculated and used when selecting new boiler?
4 - Does water line return to normal after boiler cycles off or does boiler flood?

jjheat

Yes I measured all radiators and calculated square foot of steam. Yes the water line returns to normal after it cycles off on low water. Runs for 2-3 minutes, then cycles off for 45-60 seconds on low water, then water level returns to normal and starts back up.

jjheat

There is a crawl space in 1 area where the steam main ends and they ran return up higher in crawl space. Horizontal section of the return is about 10 feet long then comes out of the crawlspace and drops down to the floor in the main basement level.

nicholas bonham-carter

Could that return be close (a foot or so) to the waterline height?
The only thing which can be done is to raise the return higher, or put a check-valve on the return (band-aid, to be avoided if at all possible.)--NBC

jjheat

So run the return same height as the main in the crawlspace, then drop down?

jjheat

If memory serves me right that return pipe runs within a footof the water line horizontally. I think i will try check valve first before repiping line to see if thats the fix.

Steamhead

Have you checked the gas input rate? Might be too high.......

Eric_32

The boiler water line (middle of the gauge glass) has to be at least 28" below the lowest steam carrying pipe, called the "A" dimension in Dan's book.

jjheat

The lowest carrying steam pipe is 32" above the water line. And yes i tried down firing the boiler too and the water still disappears. I think NBC has a good point about the horizontal return line. New boiler water level is about 6-8" above where it was, as we poured a pad for the boiler due to flooding in the basement

nicholas bonham-carter

Good thinking professor S, clocking the gas meter should show the burn rate.
The old boiler must have had a higher waterline, which put that crawl space return under water.
The new boiler might be raised up to match the old waterline. The check-valve solution, can interfere with the gravity return in getting water back to the boiler, which is why I consider it a bandaid.
Much lower pressure could keep the waterline from rising so high in the returns-such as 2 ounces, regulated by a vaporstat, and verified by a 0-3 psi gauge. This will need Massive Main Venting.--NBC

jjheat

And i should lower the return line below the water level as well? Not that hard of fix. A little digging and 2 pieces of pipe and i will be bellow water line.

vaporvac

I think you guys were posting at the same time. The waterline appears to be higher with the new boiler, not lower (as is usually the case).

Tonski

I had problems recently with my boiler, it was malfunctioning and I didn’t know what to do but then my friend told me about this www.gasboilerspareparts.com, it helped me a lot, I managed to get the part that was broken in the first place and replace it. Now it is working like never before.

jjheat

Thankyou to NBC for the advice. Turns out the new higher water level in the system was about 3" below the horizontal section of the return piping in the crawlspace and my disappearing water was filling that pipe up. Cutout that section and repiped it down well below water line and system is operating beautiful now. No short cycling and since i skimmed the crap out of it, no surging at all.

nicholas bonham-carter

We had that problem, and as with your situation, it was the mystery from hell. All the operating waterline disappeared from our Peerless 211A, (1,050,000 BTU-a lot of water!!!).
You an demonstrate how important how high water rises in the returns, by greeting some clear half inch tubing, and with appropriate garden hose barbs, connecting it to the open boiler drain. Suspend the open end from the ceiling, and you will see the waterline rise quite high!
Glad to hear you were able to solve the problem-thanks for letting us know.--NBC

nicholas bonham-carter

"How important low pressure is, and how high water rises in the returns"
Damn cut and paste when you don't want it!--NBC