Firing rate

Post23Preservation

I have a single pipe steam system with 460 square feet EDR run by a Peerless ECT-05 Boiler fired by a recently installed Carlin Gas Burner (recent conversion) drilled to fire at 150 to 175 BTU/hr. I have no knocking or wet steam issues and all vents are functioning. The issue is this: the system is very slow - a couple hours to heat the eight radiators and then the radiators are not heated from top to bottom i.e. the system does not seem to fully charge and my theory is that I am not producing steam at a sufficient rate to keep up with the condensate. Another reason I think this is because the water in the glass only drops about 3/4 of an inch when the system is running. So:
1. Is the amount of water showing in the glass any indication of the volume of steam I am producing?
2. My pressure gauge (a 30 Psi job) never budges no matter how long the system runs (what kind of gauge will give me a more accurate measure and will that gauge register pressure as soon as I make steam or only when steam has filled the system?)

KC_Jones

Is this one pipe or 2 pipe? What is the boiler firing at 150 or 175? What type of main venting do you have? Those pressure gauges are useless, if you want to know what pressure it's running at you need a 0-3PSI gauge max. You want the pressure to be as low as possible on steam systems. What is your pressuretrol set to? On the surface it sounds like you might have a main venting issue, but hard to say. If you are firing at 175k that should be plenty for 460 EDR actually it's just about perfect for that boiler. The gauge glass really isn't any indicator of steam production because the condensate is always flowing back to the boiler so as you are making steam water is coming back. A slight drop is normal because there is always some amount of steam/water out in the system while the boiler is firing.

Fred

Two hours to get steam to the radiators is way wrong. Are you sure the burner is adjusted correctly? Is the gas Pressure at the boiler and coming into the house what it should be? How old is the boiler? Are you sure it doesn't have a rot hole somewhere above the water line? Do you see an excessive amount of steam going out of the chimney? You say your vents are working, do you have enough venting on the Mains? Something is way wrong.

You should put a 0 - 3PSI gauge on the boiler to see what is happening pressure wise but it doesn't sound like there is any pressure. Pressure should be relatively low (in ounces) and build as the system fills with steam.
- Here is a site for the Low Pressure gauge most of us use: http://www.valworx.com/product/low-pressure-gauge-25-0-3-psi
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Post23Preservation

I'll check the firing rate again - thank you for the heads up on the gauge. No rot hole (boiler is 2007) and three main line vents on all three branches ( pretty big building: 1867 church)

KC_Jones

To know for sure if you have enough venting you need to measure all the main lengths and diameters which allows for calculation of air content and then main venting can be determined from there. There are a ton of different main vents on the market so having 3 vents on each main might be enough it might not. Depends on what type of vent they are. I have a 1500 sq ft house and have 3 vents on each of my mains as well. Fred is correct start with that firing rate and make sure you are where you need to be...you should be at that 175 or so.

Post23Preservation

One pipe system - pressuretrol at 1psi. I'll check the firing rate, get a gauge and get back to you. Thanks for the input.

Post23Preservation

Correction: one main line vent per branch (three branches). So I will take that advice as well and measure the piping as well to make sure there is enough venting. Do I measure just the mains and do elbows and so forth affect this air calculation? If you could just give me that formula or tell me where I might look for that it would be great. Need to make sure that air gets out of the way of my beautiful steam!

KC_Jones

If you really want some education and you have 10 bucks burning a hole in your pocket I would suggest getting this e-Book from the store. It's all about venting and explains how to calculate air and helps size vents. Good info and your 10 bucks goes to charity! Basically you measure the length of pipe and there are charts that tell you how much air per length by diameter. That will give you cubic feet of air that needs moved. Then you can look at the capacity of the vents you want to use and figure out how many you need. Here is a link to the book in the store.
http://store.heatinghelp.com/product-p/300.htm

Fred

Typically, the rule of thumb is 1 Gorton #2 (or equalivent) for every 20 feet of 2" Main and 1 Gorton #2 for every 12 feet of 2-1/2" Main. Don't wory about elbows, justtotal length. If you don't have the heigth for Gorton 2's, it takes 3 Gorton 1's to equal a Gorton 2 or 2 Hoffman 75's

Post23Preservation

I'll follow up with my measurements and let you know how i get on with your suggestions after the weekend. Just FYI, I have 4" inch mains which make long runs so its a big system

KC_Jones

4" mains and only 1 vent, yeah even if it was the biggest vent available (Gorton #2) you don't have enough.

bob_46

Is all the piping insulated ?

Fred

Post23Preservation said:

I'll follow up with my measurements and let you know how i get on with your suggestions after the weekend. Just FYI, I have 4" inch mains which make long runs so its a big system

a 4" main has .09 Cubic feet of air per foot of pipe. The gorton #2 can vent 1.1 Cubic feet per minute. You may need the equalivent of 1 Gorton 2 for every 11 feet of pipe. The limitation is going to be the size of the vent opening in the Main. If it's a 1" pipe, the most you can vent there is about 4 Gorton 2's. Anything over that will just be wasted money.

Post23Preservation

Just finished insulating mains. Also just bought the recommended valve and venting manual. Keep you posted

Fred

OK, Thanks

Post23Preservation

Ok - here is the latest. 1. There is no banging or water loss in the system. 2. The radiators get smokin' hot about 70% while the last 30% of each radiator remains cool (this is true even if the radiator vent is entirely off 3. the boiler is not being turned off prematurely by the thermostat or the pressuretrol (which is set to cut out at 1psi.) 3. My new 3PSI gauge indicates that I am never building pressure in the system - the needle moves a bit but never climbs. SO: despite the fact that my building heats, I want to fill the radiators from top to bottom and the system never shows a build of pressure. In short the system never fully charges no matter how long the boiler runs. why?

Fred

One possibility is that the trermostat is being satisfied before those radiators can heat all the way across. Try putting a smaller vent on the radiator that is in the room with the thermostat (or turn the vent upside down to close it) and let the boiler run and see if they get hot all the way across. It's is not unusual for rads to only get hot part way across, depending on outside temps. That's not a bad thing. My rads only get hot all the way across on the coldest days of the year. Probably 90% of the time they don't heat all the way across But the house reaches temperature (which is the goal).

KC_Jones

Post23Preservation said:

3. the boiler is not being turned off prematurely by the thermostat or the pressuretrol (which is set to cut out at 1psi.)

You say prematurely, but is the thermostat shutting it down when you reach set point? I agree with Fred you really shouldn't heat the whole radiator unless you are at design temperature. For me that is 7° and I am pretty much never there. At 25-30° my boiler runs maybe 20 minutes per hour and never heats any rad more than halfway.

Post23Preservation said:

My new 3PSI gauge indicates that I am never building pressure in the system - the needle moves a bit but never climbs. SO: despite the fact that my building heats, I want to fill the radiators from top to bottom and the system never shows a build of pressure. In short the system never fully charges no matter how long the boiler runs. why?

You don't want pressure....what you are seeing on your gauge should make you happy. Low pressure steam moves faster than high pressure steam, your system sounds well matched. I am curious about the comment "no matter how long it runs" Have you tried turning the thermostat up to say 80 and see what happens? Or are you saying the boiler is firing 24/7 and this is what you are seeing?

Post23Preservation

Yes, I turn the thermostat way up so that it remains unsatisfied - the boiler runs, radiators heat and the pressure gauge remains very near zero. If I set the thermostat to the set point of 65, yes then it becomes satisfied and shuts off the boiler. Just wondering why that pressure gauge doesn't creep up a few ounces. Good news about not having to heat the radiators the whole way but I did think that if I could heat them through once they would spend a lot longer "radiating" after the boiler stops firing. Also, not to beat a dead horse but what is the point of the gauge if the needle just bounces along at zero?

KC_Jones

The point is if something goes wrong such as a pressuretrol failure, or a clogged pigtail you can see a higher pressure than normal and do something. The 0-30...who knows what it may or may not read. The low pressure gauge allows you to actually monitor what is going on. If you are hitting your set point you are fine. My example of 80, if it's cold enough outside could theoretically be impossible. Remember in theory your boiler is sized to heat the space on a certain day to a certain temperature. You can't just run it as high as you want. That could be what you are seeing. IF it is what you are seeing then count yourself lucky because it means you have a well matched system which is good for your bank account. Keep us posted on your venting. If you get that main venting in order you will see a speed difference in the system. It should heat much more quickly than it does now. Good luck with everything and keep us posted!

Fred

If you are running the boiler for extended periods of time, like turning the thermostat up from 65 to 75 degrees, it should build a few ounces of pressure unless it is so amazingly matched to the total radiator EDR, or it is undersized for the attached Radiation or it has a crack or hole in the boiler block or elsewhere in the system.
I know you said that the boiler doesn't have a hole or crack because it was installed in 2007 but that is still 8 years old and sometimes things happen. Check the chimney for excess steam coming out of the top of it when the boiler is running.
My boiler only builds about 2 ounces of pressure on a normal cycle but it does build that little bit of pressure. That gauge you installed is for you to be able to see what the boiler is doing and, as an example, without it, we could not have this conversation.

Post23Preservation

Thank you gents - I'll keep you updated and really value your input.

vaporvac

Have you measured the edr of your rads and compared it to your boiler rating? If we know how well that compares we can eliminate that as a source of any problems.

Post23Preservation

yes.

Charlie from wmass

Are you sure you do not have a hole in the boiler? Have you clocked the gas meter? 2007 it could be a leaker. Gas manifold pressure? Was a combustion analyzer used to tune the burner?

Post23Preservation

Here a little refinement: building and rads heating nicely - zero H2o loss and the pressure gauge is actually being sucked BELOW zero - and there are no cracks in the boiler and I don't see steam coming out the chimney. It is true that the chimney was recently lined and has a foot foot long draw... So weird

Fred

Sounds like your boiler is well matched to the radiation in the house. Check the total radiator EDR to the net sq. ft. of steam output of the boiler. It could be slightly under sized. Can't be leaking or steaming water away. Be happy with the low pressure!

Charlie from wmass

How was the burner tuned? Too much combustion air makes for weak heating.

Post23Preservation

50 foot long draw ( not "foot foot") what might cause. Pressure gauge to do that? Also. When I close all the radiators ( shut them off entirely) the pressure gauge begins to creep up toward zero

KC_Jones

If you don't mind reading there is some discussion about vacuum in the gauge in this link. Most of it is theory though as not everyone sees the same thing and not everyone completely agrees on reasoning. A lot of us (me included) have seen the vacuum phenomenon so you aren't alone there.
http://forum.heatinghelp.com/discussion/152691/going-commando/p1

Post23Preservation

The gauge simply wasn't zeroed properly so I thin I am in fact registering several ounces of pressure. Moreover, I. An get that pressure to creep up by lowering the EDR (closing some radiators) SO - maybe I can turn my attention to venting and thermostat location in order to hit the sweet spot!

Fred

Sounds like you are getting there!