Taking long to heat

Ori

The WM EG-50 is taking long to heat two floors.
Its 446edr capacity is matched to the connected radiation (449 connected). It's a 3 level building where the 1st and the 3rd floors have 8 radiators each, and the 2nd floor no longer has radiators, and the risers are capped under the new woodfloor.

Shortly after the boiler starts the 0-18oz gauge shows about 5oz, even before the main vents are closed (there is more than adequate amount of main venting: 2 bigmouth and Gorton#2 at the end of the 3" main, and 1 bigmouth and 2 Gorton#2 on 2" main.
Please see attached video of the pressure gauge right after the start. Is it normal to have such pressure even before the mains close? Or it's an indication of obstruction somewhere?

Also might be relevant is that some of the air vents (maid o mist) get full of water, and prevent steam from going into the rads. Both on the 1st and 3rd floors.
Further, sometimes it happens where the rad stops heating, even though the gauge shows 9oz at the boiler! When I completely remove the vent, I feel only very little bursts of steam, very insignificant; feels that the steam is trapped somewhere, as with 9oz at the boiler and the vent is completely off, I'd hope to see good amount of steam flow.
By the way, the 9oz of pressure can show itself at the beginning of the cycle, as well as towards the end.

The boiler is fairly clean (I think); and was skimmed several times recently.
Another thing that I noticed is that the water in the sight glass goes down quite significantly sometime in the middle of the cycle, but the two vertical condensate returns were also snaked and cleaned recently.

It used to be the case where I'd see not pressure during the heating cycles, but only towards the end, and that happened when all the rads were fully hot. Something isn't right, and it takes long time to get all the rads fully hot, close to two hours...
For example, two days ago the temperature was 33 degrees outside, and after 50 minutes of the boiler running, only about 60% of the radiators were hot.

Also interesting, the vent on the riser of one of the radiators was also cold even after the boiler was running for a while, indicating something is trapping the steam somewhere. (by the was this rad (see pic) is now closed in order to reduce radiation, to match the connected sqft to the boiler rating for a fair test. But the riser vent still needs to be hot, even though the rad gate valve is closed...

Here is a video of the pressure gauge a minute after the boiler starts. As you can see the pressure goes up to 9oz within a minute, even before the main vents close!

https://youtu.be/KrK1KFsOcts

What can it be?

Separately, how many btu per sqft is advised for the Chicago area, roughly, on average? I read some suggest 35btu/sqft, while others 40-45. And Google suggests "50 BTUs of heat per square foot" for Zone 5 (Chicago).

neilc

just for giggles,
and because this is what I type while beating dead horses,

take your gage off and with your mouth, blow back into the boiler,
there should be slight resistance as you clear the water in the pigtail,
then it should blow freely,
refill a shot glass or 2 before putting gage back on,

see my signature

Jamie Hall

When did notice the change in behaviour? It does seem as though there was some kind of problem -- but my first suspect would be a change in pipe slope, or a sag somewhere, which is blocking steam flow -- both to the radiators and to the main vents. Can you check for that?

mattmia2

Is the water line stable while this is happening? Is there any "treatment" in the boiler water?

When was that new radiator added, what happened to the oils that were in that?

neilc

when you see that water level drop in the sightglass,
is this triggering the LWCO, and shutting down the fire?

Ori

thanks for the guidance, I’ll look for sags in mains. 

The water treatment is 8-way, to keep it slightly basic. 

The water level does go down a lot, but the boiler has been working nonstop for the past 5 hours (0° now here) with no LWCO interruption…

dennis53

Seems you have done a good job walking through the troubleshooting steps and I really don't know what it could be.
One thing that looks a little unusual is that horizontal portion of the equalizer immediately below the header. Could you show a photo of the equalizer and how it ties into the returns and Hartford loop?
Also a photo of where the 2" main splits off the 3"?

EBEBRATT-Ed

I agree with @Jamie Hall your getting water in the air vents and if everything is pitched properly you shouldn't

dabrakeman

Is it correct to assume you had a reasonably working system before removing the radiators on the second floor? If this is the case then obviously the focus would be on what did this system modification do to the overall system. I would focus on how disconnecting the second floor radiators from their risers may have possibly caused a change in the riser height leading to a sag or some pitch change in the mains below or other takeoffs from the shared riser?

WMno57

Ori said:

Separately, how many btu per sqft is advised for the Chicago area

I'm about 70 miles SE of you. My boiler is having a harder time keeping up today than it did a few years ago when we hit -20. I think the difference is infiltration from high winds. These are extremely unusual weather conditions. I think if you were radiated to keep up with today's conditions, you would be over radiated for 999 out of a thousand other days.

neilc

neilc said:

when you see that water level drop in the sightglass,
is this triggering the LWCO, and shutting down the fire?

Ori said:

The water level does go down a lot, but the boiler has been working nonstop for the past 5 hours (0° now here) with no LWCO interruption

well that doesn't sound right, does it?
if water is dropping to bottom of sight glass,
and LWCO probe isn't shutting you down,
well, number one,
Danger,

but 2,
maybe a violent boil, which would suggest requiring more skimming, is keeping the probe wet enough,
and at the same time throwing wet steam up into the system, and to those spitting vents,
it's kinda hard to judge a good skim thru that 90, and that long vertical drop,
consider removing the vertical and 90, and do some more skimming while you observe proper flow from the horizontal,

ChicagoCooperator

WMno57 said:

Ori said:

Separately, how many btu per sqft is advised for the Chicago area

I'm about 70 miles SE of you. My boiler is having a harder time keeping up today than it did a few years ago when we hit -20. I think the difference is infiltration from high winds. These are extremely unusual weather conditions. I think if you were radiated to keep up with today's conditions, you would be over radiated for 999 out of a thousand other days.

I think in the Slantfin spreadsheet there are numbers for Chicago (too late at night to dig around for it).

It's brutal here today - even in rooms that are warm it just feels cold....

And every boiler in my block must be leaking from the white plumes from every flue...

bburd

ChicagoCooperator said:

“ … every boiler in my block must be leaking from the white plumes from every flue...”

probably normal condensation from the combustion of gas. The exhaust is mostly water vapor, and in cold weather you will see the vapor cloud.

ScottSecor

Maybe I missed it, any chance gas pressure dropped a bit in your area due to the high demand?   Is it possible that the boiler is only firing at say 80 or 90 percent of rated capacity? 

On another note, any chance pipe insulation was removed recently and not replaced? 

reggi

To give some background and answer some questions perhaps

 https://forum.heatinghelp.com/discussion/190175/pressure-in-gauge-stays-high-after-heating-cycle-ends/p1

clammy

Have you ever wanded out the boiler bottom to remove any build up of mud ? Also aside from blowing out and cleaning the pigtail and it’s piping ,the whole sight glass assembly should be removed and cleaned of all mud there usually some and flush the tapping before reassembling. If you have a electronic low water cut off be nice and clean the probe and check lwco for proper operation While checking your piping for sags also look for leaks , are your steam main properly insulated if not the problem only gets worse w real drips in the temps and that’s when issue of slow heat distribution can appear . Have you check your gas burner to be sure there all burner tubes are firing properly , you could possibly clock your gas meter to ensure your boiler is firing at its rated input and that’s not the issue . Aside from leaks it would really suggest giving your boiler a good flushing and see what kind of muck comes out usually a full port ball valve in lieu of a boiler drain is preferred to enable decent flushing . Most think there’s boiler is filled w clean water a good flushing of the boiler usually reveals mud and mud does not make dry steam . Amazingly it is one of the over looked aspects and more then once I ve removed or cut out the plugs and wanded out the bottom of the boiler and bingo a day and nite difference in a lot of cases cut the time of steam at the ends of the mains to about 1/3 and stuff that didn’t get hot got hot . . Another over looked issue is not enough combustion air due to sealing everything up . I had one call where some smart **** sealed the boiler base on a gas fired dry base boiler it would not heat past the risers ,chipped away the furnace cement and in a few minutes the mains heated, this was looked at by pseg several times and they recommended boiler replacement .lol .Every issue has a cause figure out the cause and the issue disappears . Start w the easy stuff flush the boiler till it’s clean and then give it a go .
Peace and good luck clammy

Ori

Thank you again for your guidance.
I managed to insert a micro camera to both mains (2" and 3"), through a 1" tapping. Most parts of the mains are open and clear, just one location with some water at the bottom. It doesn't look much to me but I can be mistaken. If I had to estimate it, it's probably taking less than 1% of the pipe capacity. Please see attached two pics of totally open mains, and two pics with the water at the bottom (one in red and one black-white).
BUT! I found out that the cause for the vibrant move of the gauge soon after the start was indeed a layer of oil at the top of the water in the boiler. I skimmed it again and again, and now it looks to be working fine.

In the storm of last week, however, I had to close off few rads in order to get all the rest fully hot.
I had to keep only 394 edr of connected radiation to the boiler (446 edr rated capacity). Again, the gas pressure is set at 3.5" wc,
Admittedly, this was before skimming the boiler, so I'm sure there was some loss of efficiency.

Having said that, I do need to increase the size of the boiler, as now with two apartments connected, I added few rads to cater for about 45-50btu/sqft (as suggested for the Chicago area). The amount of radiation is now close to the next size up boiler, which is EG-55 with 521edr (current boiler is EG-50 with 446 edr). Later I plan to add few more ceiling rads in the basement, so even more radiation capacity would be needed.
I read that both EG 50 and 55 are of the same physical size. Is it possible to convert the 50 to 55? Perhaps by increasing the number of burner tubes? Or I need to actually change the entire boiler to 55?
In the meantime, do you think it's ok to increase the gas pressure to 4" in order to beef up the boiler, till it's updated for a larger capacity one?

Separately, as requested, I also add pics of the split between the 2" and 3" mains, coming from the 4" that is connected to the boiler. You can see that the Y split favors the 3" main rather the 2", but it's the 2" main that I added a lot of radiation to, as the 2" serves the north side of the building, while the south side (3") does get sun in the winter.
As a side question, do I understand it correctly that the 2" main can provide 385 edr for a parallel gravity system? If so, there's no concern as potentially there's going to be about 250 edr on that 2" main...

mattmia2

Water sitting in the main will stop the progression of steam. The water condenses the steam to water until it has heated the water to steam temp. The steam will stop at the water until the water is heated. That is what is stopping your steam. Fix that. The output of the boiler is 33 percent more than the plate says. That is to accommodate for loss from the piping but the loss from the piping is usually far less than that. Your boiler size is fine. It probably can even accommodate your ceiling radiators although if it were me I'd do that as a hot water loop.