Boiler piping vs recommended water level

ChrisJ

I've been really sick and in bed all week and had a lot of time on my hands for thinking. This is usually never a good thing but here it goes.

The recommended water level for a boiler is likely based loosely on the recommended piping from the manufacturer. If this is true, wouldn't it suggest that using larger and more piping could allow us to raise the water level slightly which should also achieve better efficiency and perhaps even extend block life?

For example, the typical residential boiler usually calls for a single 2" riser. By using two risers you greatly reduce the amount the water gets pulled over towards that riser which means dryer steam. But, does it actually mean we get to cheat a little as well?

I've raised my water level to around 3/4 of the way up the gauge glass, where on this boiler 1/2 is the recommended level. To see whether or not this has caused problems I'll be pulling samples from my wet return and checking the TDS level. If it goes up from 2 PPM I can assume I am getting wetter steam than previously.

Curious to see what everyone's thoughts are on this? Good bad, ugly, tell us what you think.

Fred

Chris, I keep my boiler at 3/4 full as a norm but I have a 32 year old Burnham and the block is a lot larger than the newer boilers. I think the water level recommendation from the manufacturer has more to do with having enough of a steam chest remaining in the block to adequately supply the rated EDR requirements. If the riser and header is properly sized and installed, the steam should remain pretty dry regardless of a slight variance in boiler water level. That's my opinion anyway.

Mark N

Chris, when you raise the water to the 3/4 mark, how much space is left to the top of the boiler? The amount of room between the NWL and the top of the boiler in most cases is marginal to begin with. I usually keep my water level about an inch above the NWL. I have a small boiler (Burnham IN-4) and use both 2 inch tappings. The steam exits the boiler at 10.5ft/sec. Very little to no water leaves with the steam. My water level only drops about an inch under full steam.

JStar

@‌ ChrisJ

Get well soon! I'm sure you're torturing your poor wife talking about steam all day.

I've thought about ways to add MASS to the boiler to increase efficiency, in the same way that a 3-pass boiler does. I've always wanted to try to experiment with adding pieces of cast iron inside of the boiler, or on top near the flue openings.

Mark N

Also Chris give Noel Murdough's web site at look (sites.google.com/site/steamheating/home)

Bug512

Hope you are feeling better...

This is the recommendation form my boiler manufacturer:

"Use the following procedure for initial start-up of the boiler:
1) Make sure that the boiler is filled with water to the normal water line (28 3/4 inches above the floor or pad on which the boiler is installed)"

This placed the water level at around the 2/3 mark. I p touched the 28 3/3 level. So far the water level drops a maximum of 1" now that I have skimmed and cleaned the water the glass is nice and clean with almost no water movement. I am staring to think its a lot about water quality.

Let us know your findings.

ChrisJ

I'm feeling quite a bit better now thanks.

I believe Burnham recommends the gauge glass be around 3/4 full.

With my gauge glass on my EG series 3/4 up and running normal cycles all day I just measured my wet return and found 1ppm. This shows I still have very dry steam. Wondering if I should push the envelope and go higher?

If I start pulling any significant amount of water into the mains it should become obvious very fast via the TDS measurements. 0ppm = pure distilled water.

ChrisJ

Something else I've been thinking about is the EG series goes from a tiny I think 3 section, to huge ones with what, 8-10 sections and yet the steam exits through the same two areas. I would think if you pipe an EG-45 like mine the same as they recommend piping an EG-85 then you should easily be able to raise the water level quite a bit.

ChrisJ

@MarkS‌,

Nope, where I'm at now, still 3/4 up the Dwyer gauge is acting basically the same way. 0.5" during a typical cycle.

I wonder if that extra inch or so of water gains me anything noticeable?

Fred

I suspect you may not find out until you get closer to a design day. I would think during milder weather, the boiler isn't really being tested/challenged at all. Again, my suspicion is, on a design day, that little extra space in the steam chest is going to be important.

ChrisJ

Fred said:

I suspect you may not find out until you get closer to a design day. I would think during milder weather, the boiler isn't really being tested/challenged at all. Again, my suspicion is, on a design day, that little extra space in the steam chest is going to be important.

Design day for my system according to my heatloss calculation is -50F and will never happen in NW NJ. Coldest I've seen so far was -5F though I've heard rumors of -17F in the not too distant past from neighbors.

Fred, keep in mind as steam pressure increases the turbulence in the boiler decreases as shown in this video : http://youtu.be/-bGkiq9QDXc

Point being, on a colder day I should have less carry over if anything.

Fred

If your design day is truely -50, that's significantly different than most, and you are right, you probably won't ever get to fully test the full capacity of the boiler. I'm at a bit of a loss as to how you get a design day of -50 without excessive radiation throughout the house and a boiler that then matches that EDR.
I agree that turbulance decreases as pressure increases but it would have to increase significantly beyond what any low pressure steam system could run at and consequently the difference in a few ounces won't significantly impact or calm the turbulance. The video you reference above shows the difference in turbulance between a 50PSI boil and a 100+PSI boil. Not relavent to our senerio.
I'm just saying maybe it makes more sense to talk to the design engineer of you boiler maker and get his/her perspective on all the factors that went into making the "half full" recommendation/guideline. JMHO

ChrisJ

Fred said:

If your design day is truely -50, that's significantly different than most, and you are right, you probably won't ever get to fully test the full capacity of the boiler. I'm at a bit of a loss as to how you get a design day of -50 without excessive radiation throughout the house and a boiler that then matches that EDR.
I agree that turbulance decreases as pressure increases but it would have to increase significantly beyond what any low pressure steam system could run at and consequently the difference in a few ounces won't significantly impact or calm the turbulance. The video you reference above shows the difference in turbulance between a 50PSI boil and a 100+PSI boil. Not relative to our senerio.
I'm just saying maybe it makes more sense to talk to the design engineer of you boiler maker and get his/her perspective on all the factors that went into making the "half full" recommendation/guideline. JMHO

You hit the nail right on the head Fred.
This house was built in the 1860s and the steam heat was done in the early to mid 1920s. Right when excessive radiation was at its peak I believe. I can easily heat my house with the windows open.

Mark N

Ok Chris you caught my interest. Let's see those calculations. For NW New Jersey I would believe -15 as a design back then. At full capacity how many BTU's per sq ft can your rads put out. I'm 64 BTU's per sq ft.

ChrisJ

58.8.

392sqft in a 1600sqft house.

Wow, you're more oversized than me! That's kinda scary.
I should admit I used storm windows and minimal attic insulation in my heat loss which were obviously not here when the system was installed.

BobC

My 1918 6 room house has 203 of EDR (no radiator in the kitchen) and the house is about 1100 sq ft. That works out to 44 btu per sq ft, a little skimpy for an old balloon framed house one block off the ocean.

Bob

Mark N

I like being oversized. Last winter when it got near zero my house was very comfortable. Don't you remember reading the threads last winter of the people with radiant systems designed for 15 degrees. The boilers never shut off and the couldn't get the temp above like 65 degrees. The colder it gets the better a steam system runs. More frequent cycles, faster steam distribution. It's 0 to -5 out and your steam system doesn't even break a sweat to keep the house at 70. In newer house with insulation and FHA or radiant. The boiler or furnace never shuts off and your probably cold to boot.

KC_Jones

I am at 265 ft² in a 1500 ft² house. My problem isn't lack of radiation it's just not all in the correct locations. Due to previous remodels neither of my upstairs bathrooms have heat. They stay warm enough, but could use some help. lol

Fred

I have about 52 BTU's per sq ft, 5000 sq ft house, triple brick, 3 floors plus unheated basement. I've been to -17 with no problem maintaining temperature but last winter we had two days with winds that created a -40 wind chill and my boiler was challenged but pulled through on those days.

ChrisJ

I don't know.
To be honest if I could redo my radiation I'd aim for maintaining 70F @ 0F and when it goes below zero just deal with it.

I don't think 65F is uncomfortable on the rare occasion and the smaller system runs more efficient 90% of the time.

KC_Jones

I have been in this house for 12 years and have had about 20 days that my boiler has fired almost continuously to keep the thermostat happy.

Mark N

Chris you might not find 65 uncomfortable, but what about the wife?

ChrisJ

I don't want to talk about that.
I'm getting bit....... complained at about 72F.

Fred

He's right though. On those few days where you have to settle for 65, it's not a problem. I keep mine at 66 all winter long and when people come into my house, they note how nice and warm it is. If anyone decides it's too cool, I tell them to go out and come back in.

KC_Jones

My wife complains all the time about it being too cold, but she is sitting there in a t-shirt and bare feet. lol yeah it's miserable in here! I keep mine at 70.

ChrisJ

I'm telling ya.
You give them a degree they take two, you give them another and before you know it you're up to 78!

Mark N

Happy wife happy life

KC_Jones

Ok since we are just talking. I have 3 kids 2 of them are twins. My wife was pregnant with them during the summer. I cool with window AC units. I had a 12000 BTU window unit in our bedroom turned to the max. I would close the bedroom at night so I was using 12k BTU's in a 180ft² bedroom and she was laying on top of the covers complaining how hot it was. Oh and the ceiling fan was running on high. Now that is complaining to the max. I just kept my mouth closed and added a blanket to my side of the bed.

Fred

Sorry KC, I'm with her on summer cooling! I have a 5 ton and a 3 ton central air systems and I keep the house at 68 from May 1 through till they won't come on anymore because the in-house temp is already lower, like around the last week of October. Then my beloved boiler gets fired up!

KC_Jones

Don't get me wrong I like AC, but 12000 BTU for one bedroom was a little ridiculous. Seriously it was like 60 degrees in there that summer.

ChrisJ

However 12k in a room that small means terrible humidity removal. I run an 8k in our bedroom and even that's big most of the time. I keep the bedroom @67 in the summer and 65-66 in the winter. Sometimes it'll creep up to 67 depending on how the trv behaves. Point being 12k in a tiny room could easily make it feel warmer than a smaller unit at a warmer temp.

KC_Jones

lol Chris normally the doors are open so it is doing a large chunk of my second floor, but the year she was pregnant...I had to close the doors at night or she couldn't sleep. Believe me closing those doors made it cold.