Boiler Water Level, New HB Smith 19HE, Beckett cg10 gas, One Pipe System

Doug83

I have a question about an installation that was just completed, replacing a 45 year old American Standard atmospheric boiler (520K in) with HB Smith and a Beckett Power Burner. After a few installation errors ( the burner didn't have the air guide required and tripped every few days and then near boiler piping was changed causing only half the building to get heat...) that was all corrected. Now I get heat to all five floors ( 5 apartments), 3 radiators in each with a bathroom riser.
I ran the boiler today for the second day in a row to check the riser and radiator temperatures. Everything was at 200'F after about 20 minutes of running, with the radiators working a good 5 to 10 minutes to get fully hot after the boiler shut off after reaching the set point in the hardest to heat room, But here is my concern. I started with the boiler water level about 1/2 inch higher than "normal steam water level" in the sight glass. When the boiler shut off, the water level was lower by a half inch to "normal water level " line. 20 minutes later, the water level was an inch higher than my starting point. So 1 1/2 inches higher than the "normal water level" line. Is this normal? or is this an auto feed water/condensate flow balance issue? The boiler has been running for hot water for about 25 days now, but only ran for heat about 8 times. I have only checked this water level issue after the near boiler piping issue was corrected getting steam to all four risers. So essentially, it has a different operating characters now and this is the second run. Should I be concerned that the boiler water level will keep rising, running past the top level of the sight glass. Could it be that the water needs to be treated (during the cycle, the water level rises first slowly to a max of 1, 1.25 inches, then lowers while it is steaming to where I started but bounces up and down about .25 inches.) Should I cut the auto feed valve position to 5%? Ay ideas or questions are more than welcome!!... I am afraid of running the boiler while I am not around until I can see how this operates over a few days on auto....

Jamie Hall

Patience. If the boiler keeps doing what it's doing now, you're probably fine. There is a recommended water level, of course -- but getting an inch or two above it isn't going to be a problem (provided your near boiler piping is at least decent, which I gather it is). Nor is a drop in water level while the thing is steaming unusual. There is remarkably little water in newer boilers, and even the small pressure changes involved can back a surprising amount of water into the pipes coming down to the wet returns. Not to mention the volume of water in the form of steam out in the system, and the condensate making its way slowly down to the wet returns and the boiler.

What you should do, though, is monitor the system for a bit to make sure that the auto water feeder isn't overfeeding the system (there are those who dislike autofeeders -- well and good, if you can check your level every day or twice a day in really cold weather, but not everyone can do that!). If it seems to be, most autofeeders have some sort of time delay, and you could try increasing that -- assuming the thing isn't actually leaking, that will usually take care of that problem.

The amount of bounce you are seeing while steaming is admirably small. You don't need to do anything further in that regard.

nicholas bonham-carter

Cut off the autofeed for a few days, and see if the waterline stays the same at rest.--NBC

EBEBRATT-Ed

I agree wit @nicholas bonham-carter Fill or drain the boiler until your at 1/2 a glass. shut off the mu water . Run the boiler a few days and monitor the water level. You haven't given it enough run time with the piping changes you have made.

If you find the water level constantly low you may have leaks or leaking air vents.

A water meter in the boiler water make up line is good insurance and makes it easier to monitor excessive water use which can kill a boiler

Doug83

Thank you guys!! (nicholas bonham-carter , EBEBRATT-Ed and Jamie Hall ). Follow up question.... should the auto water feed ( mcdonnell miller) be supplying water if the water level the entire steaming cycle never dips below the normal water level mark? When are these feeders usually given a permissive to open? Is it 1 or 2 or more inches below normal water level, or, does it open and feed just because i am steaming?? I like the idea of closing all water feeder valves and seeing what happens differently... I think that is an important test... If the level stays close to where I started at the end of a cycle, and the water feeder is not supposed to be feeding near the normal water level range, should I do this broken union test i see in the MM operating instructions?.... Jamie Hall's comment is interesting too... i have a whole new technology connected to an old one pipe system with a dry return beneath the steam supply's that had no main steam vents or steam traps... I just drilled a tapped the risers on the floor below the last floor and added Gorton D air vents to help get the steam move faster...it helped a lot.... one last item... after I do all above... do you think It would help to ad some type of vent device on the dry returns? one step at a time...but just thinking ahead, i feel like I can't be away for more than a day as it is getting cold in NYC and i do not live close the building . Thank you!!

nicholas bonham-carter

Yes vent those dry returns generously, to get the steam filling the horizontals first, and then rising up.—NBC

Doug83

@nicholas bonham-carter, @Jamie Hall, @EBEBRATT-Ed
Gents- thank you again... After some of the earlier installation errors on this project, I decided to take a look at the feed water installation guide... I didn't say earlier, but they installed a McDonnell Miller 51-2. Based on my observations for starting water level and ending water level, this now makes complete sense! take a look at the Design Basis installation sketch I made as compared to the Installed condition. They are off two inches, so any water level that was below say 0.75 inches above the normal water level mark on the boiler was calling for feedwater..... I did not get a chance to run the boiler with the valve off completely because I wanted to run it once again in its current condition and repeat the results again...it got too warm outside today and the top floor was at 78 degrees so I had to stop... but I think we got it...! Thanks again

Doug83

Without having to study those drawings... basically, they were supposed to install the casting line of the feed water valve 3 1/8 inch below the Normal Water Level (NWL) on the boiler. They installed it 0.75 inches below NWL.

EBEBRATT-Ed

Apparently another installer that cannot read. Your Smith distributor can get you a drawing of ware Smith wants the control mounted.

Your first drawing looks correct to me at a quick glance.

The installed drawing is totally wrong.

If your first drawing matches what Smith wants (perhaps you got this information from them?) the go with that and get the installer back to move the control. With 1" control tapings and the water line rework it's a little bit of work.

If you have other water line controls, and other safety controls I would review all the work they did before you have them back to make any repairs. Also check the near boiler piping compared to the install manual.

Good for you catching this mistake. It makes me leary wondering what else they did wrong. Hopefully nothing

Doug83

I tried calling Smith on Friday to confirm the information for mounting the McDonnell Miller feed water valve. However, the Smith Boiler has a plate right on the front of the boiler showing the Normal Water Level Line, and the drawing (which I see now and will check on site Monday) says it has to be 41 1/4 inches up from the floor. The Mcdonnell Miller installation instructions are where I got the requirement to install the valve casting line 3 1/8 inches below normal water level. So.... when I called my installer before I posted this on Heating Help, and I told him of this problem, and that I keep lowering my water level to Normal Water Level and that after a cycle it keeps going up at least an inch and half above that level, he said, "leave it alone, it will find its happy place." Is the main reason I am arguing for movement of the water feeder that higher water levels will impact the steam quality and the space the boiler needs to make that steam in a narrow boiler section?? I will confirm with HB Smith, but I just want to make sure I know how to respond to "it doesn't really matter that it is higher by a few inches."

Fred

It does matter that it is a few inches higher, for the reasons you stated. Also, be aware that the label they put on some of these boilers to indicate the "Minimum Water level " is not at all consistent across the industry. Some manufacturers place the arrow at the actual "Normal water line" and others place it at the actual "minimum water level" that the boiler is not in danger of reaching a dry fire situation. My boiler is labeled at the actual "Minimum water level" where water must be added. This installer has the LWCO in the wrong location and having the water level that high is not its "Happy Place".

Jamie Hall

May I gently beg to differ... a little. The happy place is also dependent -- a lot -- on the quality of the near boiler piping. If you happen to have a well-designed and well constructed drop header, a higher than specified water level -- so long as it is well within the gauge glass -- is not going to cause a problem. Why not? Because the situation is that the operating water level in a boiler is a compromise between getting all of the surfaces exposed to flame/hot combustion gas covered with water, to prevent them burning out, and keeping the water level low enough to reduce carryover (you can never completely eliminate, without a steam drum). Older boilers had a rather capacious space above the fired area which reduced to the problem considerably; some even did have a steam drum. In newer boilers, to get the efficiency up and the response time down, that space has been reduced (sometimes to the silly point).

Bottom line: if you have a good drop header or a steam drum -- or both, as I have on Cedric -- you can run a lot higher and still have dry steam in your system. If you don't, your margins are much smaller.

Doug83

@Jamie Hall @Fred Thank you for your insight! So here is my problem... we are just completing this installation and I am sure there is a warranty of sorts from HB Smith. I also need to be inspected by the NYC Boiler Dept.. I think the problem I see is that where the "tight water shut off" position is in the drawing above for "current installation" does not leave a lot of room to LWCO ( Fred- my boiler has a label for "minimum permissible water level" and "normal water level" , say ~ 4 inch difference on the sight glass) if you leave the water level at the tight water shut off level. In any case, I think my biggest concern is that if I wanted to get the recommended "swing distance" to LWCO (like 4 inches), the water level would be about 1 inch from the top of the sight glass.....While I understand the comment about steam quality being subject to many design and operating conditions....unless I am able to test it, I don't know what I have. I guess what I am looking for is a strong argument to my installer for me insisting on moving it if that is the right thing to do. One argument has to be the response from HB Smith... which I will get on Monday, and another should probably be, i just paid everyone for a new installation ( including a new chimney), why should I compromise on design and possibly operation at this point? I just can not believe the amount of errors there were on this installation....all of which I had to find and get help from you guys on... In each case, the installer's service guy would say " jeez, I am not sure why that is happening." Or in the last response, let it find it's happy place. "Let it find its happy place" as an answer for a technical operation and design issue is what scared the hell out of me, and prompted me to get insight from experts like you guys!

Fred

@Doug83, I would think the instructions from HB Smith would be sufficient to make the contractor correct this issue. If it were me, I'd arrange a conference call between the contractor, you and HB Smith so you all hear the same thing at the same time. You should not need additional arguments with your contractor to make it right, assuming HB Smith agrees with you.
The other argument, if you need one is that the LWCO should trip at some level below the Normal Water level, not at the Normal water level and over fill the boiler above what is specified as the Normal Water Level. Your I&O Manual will most likely also state, in inches, how high the Normal Water level is, off the floor. If you have a custom installation, as @Jamie Hall has, with a steam drum, that water level may be somewhat variable but still doesn't have to be above what the Manufacturer defines as the Normal Water level (I don't think???).

Doug83

Great points and suggestions... and yes, I found the drawing on line showing that the normal water level for steam operation is 41 1/4 inches above the floor of the boiler. I wish I was there right now to measure where it is, but I am pretty sure i am going to be at 43+ when the feedwater valve closes drip tight, giving me a short swing down to LWCO. I will arrange the conference call. Now I think I know why the start up tech was like, ummm, lets throttle the shutoff valve after the auto feed side of the feedwater valve to 5% open.... it is all making sense now.

EBEBRATT-Ed

@Doug83

I have done a lot of work on Smith boilers there right in my backyard and I know one of their sales engineers really well we went to school together 40 years ago.

NO way that 51 feeder/cutoff is mounted in the correct location. It will definitely impact the boiler performance. It needs to be changed. If the mounting height for that control is not in the install manual (and it usually isn't) Smith can provide a drawing for ware to mount it.

They also make a precut piping kit but I prefer to make my own.

They will also need to know any other water line controls that have been installed on that boiler ( #63 manual reset LWCO, #150 pump control etc.) as the mounting heights have to be correlated correctly

Doug83

@EBEBRATT-Ed , Thanks again! I am going to work tomorrow to get all this information, and communicate with Smith and the installer. The secondary LWCO is a PSE-801-M-120, which from the looks of the picture on my phone, is directly in a tap provided by the manufacturer ( I hope). This should be an interesting week, and the first week of needing heat this season three days in a row in NYC. I will report back with my success story! With all the problems in this installation, I am temporarily grateful for global warming giving me a chance to resolve them.

EBEBRATT-Ed

I looked in the series 19 O & M manual and they don't give really any instructions on where to mount the controls....in the contractors defense.

Doug83

Thank you @EBEBRATT-Ed, you are right, I am only trying to get this right in a timely fashion so I don't do damage to the system.... I did call HB Smith , and Mcdonnell Miller. In essence, the installer is supposed to look at the HM Smith manual and see that NWL is 41 1/2 inches from the floor ( this is also where the NWL is marked on the front casing), and then, when installing the 51-2 feed water valve, see that the instructions say that the casting line on the valve body must be located 3 1/3 inch below NWL. I have not called the contractor yet, I am actually going today to run a heat cycle with the feed water valve completely closed with the boiler water level at NWL. This does two things for me ( I think)....1) I will see where the water level ends after the cycle, and hopefully see that it ends at NWL. I will check to see if during the heat cycle that if the valve was installed in the correct location ( with drip tight valve closure at 2 inches below NWL) that the water level never hits that low level and therefore would not put any water in the system ( i guess this is a check on condensate return speed as well). and 2) If the burner trips on LWCO, which is currently calculated at 1.625 inches below NWL in the current valve position (it should be 4 by design) then I will confirm with some accuracy that the valve is indeed in the wrong position by some 2 inches...

Fred

You are over thinking this. If the casting line, on the LWCO, is not 3.33" below the NWL, then the LWCO is in the wrong location and it needs to be relocated (which we already know).

Doug83

@Fred You are right, a fatal flaw of mine... and I am going to ask the installer to relocate the valve now. Since I did the test, here is the data.. and I guess what we would expect. With the feed water valve closed, and the starting boiler water level just a little above NWL. Once the burner started the water level would slowly rise say one to one and a half inches above where we started over the first 7 minutes, and over the next 3 minutes would then drop 1.5 inches below where we started and trigger the LWCO. IT would wait for condensate to return (50 seconds later) and then restart. It would continue to do this ( but shorter cycles now because it is going back on at a lower water level). The water rises back to the starting water point this time, and then drops back down to the LWCO over
6 minutes this time. It continued to do this 5 times until it made temperature set point on the top floor (i had it on thermostat control not the heat timer for now).

I asked this question way above before but wanted to ask more specifically. I am still worried about condensate return speed even after we change the water feeder location. I know it will perform better with just the relocation, but I have no end of steam main vents ( very little room to the ceiling), or steam traps, and no vents on the dry returns. What would be the first thing i ask for?? Would it be air vents in the boiler room right before where the dry returns elbow down to the wet returns? Thank you everyone for your experience and insight!

Fred

Ideally you want to place your vents 15 to 18 inches back from the end of a main but you can put vents anywhere after the last radiator run out on the main or on the dry return. Having said that, vents are essential to evacuate air from the mains so that steam can move through those mains quickly. They won't do anything to make the condensate return more quickly. You need to make sure any wet returns are clear. Dry returns are not likely to clog. Also, since this is a new installation, make sure the boiler is skimmed several times to get all the oils off of the surface of the water. skimming is different than draining and refilling the boiler. Skimming will take a few hours and is a very slow process but is critical to a stable water line. From reading your last post, the rise and then drop in water level seems a bit excessive and typically caused by the need for a good skim (several actually, a few days apart). When there is oil on the surface of the boiler water, the steam bubbles have a difficult time breaking through that oil layer/film and consequently can/will push water out of the boiler and into the wet returns.
BTW, there has to be a convenient place to add vents, even if it means you have to elbow over and up, between the floor joist.

Doug83

Thank you @Fred, that is why I posted the water level movement data.... I am concerned with that because I never saw that much movement in my 45 year old atmospheric boiler. The installers skimmed a few times after the install, and then last week I skimmed the boiler probably 6 or 7 times over 2 hours, just by adding water one half inch over the skim drain, waiting 15 minutes, then skimming... I am guessing this is not the right process. I will do it once every time I show up over the next week. The installer supervisors were talking about doing a "boil out " ( I think adding chemicals and heating the boiler water up?) Do you think that is a good idea? Their discussion ended with let's try skimming first.

Steam main air vents are more challenging to install due to the space limitations as mentioned , but I am sure I can find someone experienced to get it done. It is much easier to put air vents on the dry returns in the boiler room, right before they drop to the wet return. Is that sufficient there? Or do you think I should just find the right person to get the main steam air vents in?

Jamie Hall

You need both vents -- the ones on the steam mains and the ones on the dry returns.

Fred

Is this a one pipe or two pipe system? If it's one pipe, vents on the dry returns are fine. If it's a two pipe system, then as @Jamie Hall says, vents are required on both the mains and returns.
Yes, it sounds like you are not skimming properly. You don't want to fill the boiler up above the skim port and then drain it down using the skim port. That's not a skim. All that does is allow the oils to cling to the side walls as it drains down.
What you want to do is:
- heat the water up, in the boiler, not boiling
- Open the skim port
- use your manual bypass valve and allow the water to slowly rise until it starts to dribble out of the skim port, into a bucket
- continue that very slow dribble (no larger that the diameter of a pencil (smaller works better) for a couple hours. It should take maybe an hour to fill a five gallon bucket.
- when done, close the skim port, shut the water supply off and fire the boiler up.
The goal is to move the surface water/oils off of the surface of the water so slowly that you don't cause any turbulence in the boiler. Don't let them put any cleaning chemicals in that boiler. That is just a rushed way to try and clean it that doesn't work as a skim technique.
Hope this helps!

EBEBRATT-Ed

@Fred said, "They won't do anything to make the condensate return more quickly"

I disagree. The vents will break a vacuum allowing condensate to flow back to the boiler.

@Doug83 , I would suggest getting the MM #51 relocated. That's the first thing. One step at a time.

If after relocation the system heats well with no water line problems...then fine

No need to speculate on other problems or venting YET.

See what happens next

nicholas bonham-carter

As you seem to have a one-pipe parallel flow system, I would suggest plenty of main venting on the dry returns only. When you have all the main vents near the boiler, it makes it easier to keep an eye on them, and to see if one return line is slower than the others.
Putting too few on the lines may risk a higher velocity of air flowing through each one, causing some debris to be lodging in the valve portion itself.
The definitive method would be to add vents until the time of steam arrival at the end of the return is equal to the time of arrival with the vents removed, or to look for 2 ounces of back pressure at the maximum on your low pressure gauge, while the air is escaping.
This combined with slower radiator vents, will make sure the steam fills all the horizontal supplies before the risers, making all the radiators hot simultaneously.
If your boiler does not have dedicated trappings for the LWCO, then a surge column will have to accommodate the gauge glass and the M-M. This surge column may also trap oil from the surface water, which would then be flushed out when you blow down the LWCO.—NBC

Fred

@EBEBRATT-Ed said: I disagree. The vents will break a vacuum allowing condensate to flow back to the boiler.
While I agree main vents are critical to a steam system, they are closed when the return water is most needed, during the heat cycle. I don't believe they will make any significant difference to the speed of the condensate return, during the heating cycle because they are closed, as if they weren't even there.

Doug83

Excellent insight All! SO some good news, they relocated the Feedwater valve to the correct location...guess what... now my water always starts and ends near the Normal Water Level line on the boiler. I still get surging but it is down from 2 inches to about 1 1/2 inches....I will use the technique described above by @Fred to skim for longer periods of time. I like the idea of not using the chemicals if I can get the water level movement to normalize by skimming.

I have an additional question. Before skimming using @FRed's procedure, should I also do a complete boiler drain from the large bottom drain tap?If recommended, I know I would have to shut the boiler off while performing this, but for how long before the dump, and then how long to cool before I fill again?

I seem to be getting all the radiators hot. I bought an infrared gun and measure between 180 and 190 degrees at the radiators with the risers at like 200. I still want to add the dry return vents. I just need to find a "nbc call for heat" day as while I have experience drilling and tapping 1/8 " NPT, I have not done 3/4 yet and don't want to make a mistake with not time to recover...
Can you recommend a good dry return vent that is not too tall?

Fred

Has the water in the boiler been drained at all yet? Is the water in the boiler blackish? If it is clear, a good skimming should be fine. If it hasn't been drained and looks dirty, drain it and refill it, then skim. Boiler block warm to the touch is always a safe temp to drain and/or refill it.
How much height do you have for the vents? How long are the mains? Barnes and Jones Big Mouth vents are by far the best, IMHO. They are a little shorter that the Gorton #2's, solid brass, cost the same as a Gorton #2 and have twice the venting capacity. Barnes and Jones also has a Vari-vent for mains that are shorter. The Big Mouth can be ordered from Amazon but I think the Vari-vent has to be ordered directly from Barnes and Jones.
EDIT: Actually, I see that both the Big Mouth and the Vari-vent can be ordered from the store on this site!

JUGHNE

Doug, what size of pipe is your dry return that you want to drill and tap?

Doug83

The boiler was never fully drained since we started operation a few months ago.The water looks like it just has a little taint of oil in it, not bad really, sometimes it looks clear.... I skimmed again yesterday for about an 45 minutes... I will have to get a warmer day to run the skim operation longer. The building is 70 feet long, with the boiler about 25 feet in from the front. Two dry returns come back into the boiler room from the end points ( so 25 feet and 45 feet long). It appears the dry return OD's are about 3 inches. I think I understand that water contamination can cause the water to rise the 1 1/2 during the beginning half of the steaming cycle...but it also drops 1 1/2 inches at the last half of the cycle. Will the drop improve after complete skimming, or is that normal or a function of slow condensate return. I never saw that kind of movement with the old atmospheric boiler, but have it now with the beckett power burner... IN any case, the drop does not appear to cause a steaming operating problem, but it does drop below the top of the water coil for that 10 minutes while it recovers.. I have about 8 inches to work with on top of the dry return lines. I could buy a right angle drill to make the hole i guess and then tap that hole?
Thanks all

Fred

The water level in the boiler will drop by the time the boiler is at the end of a heating cycle. There is condensate out in the system that still needs to return. An inch and a half seems pretty normal to me, depending on the number of radiators, the length of the mains, returns, etc. If it is not tripping the LWCO and, in turn, not adding unneeded water, it's probably okay. It's always appropriate to have the wet returns (those below the boiler water line) cleaned when a new boiler is installed and to flush them annually, if possible but I think your concerns may be unfounded, from what you've said.

EBEBRATT-Ed

8" on top isn't a lot to work with. I think I would take it apart and cut in a tee for the vent. The vents should be 18" back from the end of the main. If you drill and tap 1/4" is probably the largest feasible size