How Much You Burning in Your Boiler Right Now?

I just looked this thread over to find BTU output for 1" line as I remember someone posting it. I could not find it myself but in the first page of this thread cabinover found on google that a 1" line is only capable of supplying 75K BTU's. If that is the case than why won't a 220K BTU boiler keep up? I have to be missing something?

swyman wrote:I just looked this thread over to find BTU output for 1" line as I remember someone posting it. I could not find it myself but in the first page of this thread cabinover found on google that a 1" line is only capable of supplying 75K BTU's. If that is the case than why won't a 220K BTU boiler keep up? I have to be missing something?

There is a caveat associated with assigning maximum BTU carrying ability to any diameter of pipe. That being the classical ideal of a 20 degree drop from supply to return. And also there is the 4 FPS maximum recommended flow velocity limit to consider.

Once you calculate the maximum GPM's of flow for a given inside diameter of pipe (see my 'flow calculator' thread), you can play games with determining the maximum BTUH that it can deliver. I don't know the ID of your 1" PEX, but lets assume 0.875 inches.

FPS flow = (0.408/ID^2)*GPM
Max 4 FPS = (0.408/0.875^2) *GPM
MAX GPM = 7.51 GPM

Ideal max BTUH = 20 x 500 x 7.51
Ideal max BTUH = 75,100

This is how a maximum "ideal case" delivery of 75,000 BTUH is calculated for your 1" PEX.

But if your "measured" (real world) drop from supply to return is 30 degrees the same pipe can deliver 112,500 BTUH, and for a 40 degree drop it can deliver 150,200 BTUH, and for a 50 degree drop it can deliver 187,750 BTUH, etc...

So in the real world it is a total fallacy that a 1" pipe can only deliver 75,000 BTUH. This is what I believe you are missing.

In the real world the system (pipe being a part of this) will attempt to deliver in BTUH's what the "users" are demanding of it. And the accurately measured drop in temperature from supply to return will be your proof of this.

I also do not believe that you understand that your underground run is a "user", and that it has demands.

I also believe that you are not understanding that you can't deliver more BTUH than the amount of anthracite that you are burning is capable of delivering. To honestly deliver an output of 220,000 BTUH requires the burning of roughly 24 to 26 pounds of coal per hour. There is no escaping this.

So basically I need a Coal Gun S-500 to keep up with my system? That would match the wood boiler rating I had that performed flawlessly. Still can't get my head around it, my crappy little A-maiz-ing heat 165k corn boiler heated the house with the same coil setup, it was in the attached garage but at that time it was not heated or insulated. That boiler was not very efficient either, just had around 12 -1 1/2" vertical exchanger tubes and the exhaust elbowed out the top, single pass exchanger, lots of stack loss. This boiler has a large burn cavity with a small hole in the top and the hot gasses have to travel back down through about the same heat exchanger tubes then out, I love the pressure vessel design on this coal boiler....How much for a S-500?

So this is just eating me up, having a good night at work and I have been reading past posts most of the night and came across this from when Matt at LL built this and here is test results:
First day of set up and testing complete, passed the low and high voltage test and got preliminary set up completed for high limit test and others tomorrow. Some preliminary numbers to consider:

Supply 184*F
Return 74*F
Flue Temp 275*F
Flow rate 24 gallons in 3.5 minutes (6.85 GPM)

So if I am reading this correctly he has 184* coming out of the boiler and it is keeping up with a 74* return temp? If that is the case then my 170* supply and 130* return should be a walk in the park for this boiler? Considering my flue temps have only been as high as 150*, this boiler has a whole lot left in it...it I could just get the exhaust out!

swyman wrote:So basically I need a Coal Gun S-500 to keep up with my system?

I'm confused. If you are not burning in the neighborhood of 430 lbs. of coal per day (18 pounds per hour) you are not utilizing the full heating capabilities of the LL AA-220. So why would this lead you to believe that you need a boiler that is more than twice as large? That will not change one thing.

Supply 184*F
Return 74*F
Flow rate 24 gallons in 3.5 minutes (6.85 GPM)

If this is correct, then your boiler is capable of delivering an output rating of 376,750 BTUH, and you already own the equivalent of a S500 Coal Gun. So no worries from the boiler side. But it also requires the burning of 40 lbs. of anthracite per hour. Is that what you want?

When you say that your drop in temperature from supply to return is 30 degrees, is that with all of the "users" simultaneously calling for heat?

You will only be able to begin to gauge the ballpark requirements of your total heat load if you:

1) Accurately know your flow in either GPM or FPS, or if you can give us a solid figure for your systems "friction head", or if you can measure the pressures at the inlet and discharge side of your circulator.
2) Accurately know your temperature drop from supply to return with all users calling for heat simultaneously when it is below zero degrees outside.

And likewise you will begin to know the demands of your loop when no users are calling by the supply to return temperature drop when no users are heat calling. But for this you will still need to know your flow in GPM under the no users calling scenario.

Most of what I have been posting across multiple threads for the past week or two has been driven by my attempt to assist you in understanding your quandary. If you do not understand your quandary, how will you ever begin to fix it? And how will you expect others to tell you how to fix it?

Also, you must abandon the bigger must somehow be better attitude.

Ok, I'll look though our thread and see if I can do it

dumb question and maybe I missed it and it has been covered already....

Is it possible to wire the power vent incorrectly causing it to spin backwards, cutting down its cfm considerably?

No, it has a plug

Folks we are so far away from basic operation here it's painful. I have troubleshot boilers furnaces and stoves for the last 40+ years and when you get away from basics this type of stuff shows up. Everything is screaming at me that this is not equipment malfunction. Assume that this is a brand new installation and he needs to set everything up EXACTLY like it's a first time burn. Forget the flows right now, forget pipe size, forget BTU's etc etc etc. Gett out of the numbers and lets get to hand operation just like it was a single burner boiler sitting there. We need to set up the boiler so it can put out it's max capacity right where it's sitting, one section at a time.

Lets set it up like it is the very first burn and eliminate one system at a time. First make sure we have the proper draft while it's just sitting there. No fire, no coal, going through. Verify Draft and write down the draft numbers. Your boiler is rated at 220K. Your power vent is rated at 280K. ASSUMING everything is set up properly, there is no reason why your power vent can't handle everything the boiler can throw at it.

Swyman You said earlier that when you have your power vent at max the baro is wide open? Is this correct? If it is you are pulling air through the baro, not through the boiler. With the baro allowing max draw through it at any level of fire there is no way physically possible that you will get the draft through the firebox that it has to have.

Put the book down because your in the real world not the book world. With all the tinkering you have gotten away from the basics required for setting up a boiler with a power vent.

Pin your baro shut and foil your baro over so no air can get through it. You need to set the power vent speed so you get settings that the manufacturer calls for. Start your combustion blower and adjust your blower inlet so you get the number you want. THEN light off the one burner and adjust your power vent for that load. Don't touch the inlet damper!!!! You only adjust your inlet damper to get the correct FIRE. Ensure that when that burner is at max burn the power vent can handle it. That power vent is large enough to throw everything from one burner at it. Set your combustion dampers where you get a good fire and leave them there.

Let the boiler sit and run for at least four hours. Then let us know what the system is doing. Stop making changes to everything at the same time.

LET IT SETTLE AND CYCLE
DONT TOUCH ANYTHING ELSE

Let us know what happens after fours hours of running like this. Once it is set up properly for one burner then we can add the second utilizing exactly the same methods.

blrman07 wrote:Folks we are so far away from basic operation here it's painful. I have troubleshot boilers furnaces and stoves for the last 40+ years and when you get away from basics this type of stuff shows up. Everything is screaming at me that this is not equipment malfunction. Assume that this is a brand new installation and he needs to set everything up EXACTLY like it's a first time burn. Forget the flows right now, forget pipe size, forget BTU's etc etc etc. Gett out of the numbers and lets get to hand operation just like it was a single burner boiler sitting there. We need to set up the boiler so it can put out it's max capacity right where it's sitting, one section at a time.

Lets set it up like it is the very first burn and eliminate one system at a time. First make sure we have the proper draft while it's just sitting there. No fire, no coal, going through. Verify Draft and write down the draft numbers. Your boiler is rated at 220K. Your power vent is rated at 280K. ASSUMING everything is set up properly, there is no reason why your power vent can't handle everything the boiler can throw at it.

Swyman You said earlier that when you have your power vent at max the baro is wide open? Is this correct? If it is you are pulling air through the baro, not through the boiler. With the baro allowing max draw through it at any level of fire there is no way physically possible that you will get the draft through the firebox that it has to have.

Put the book down because your in the real world not the book world. With all the tinkering you have gotten away from the basics required for setting up a boiler with a power vent.

Pin your baro shut and foil your baro over so no air can get through it. You need to set the power vent speed so you get settings that the manufacturer calls for. Start your combustion blower and adjust your blower inlet so you get the number you want. THEN light off the one burner and adjust your power vent for that load. Don't touch the inlet damper!!!! You only adjust your inlet damper to get the correct FIRE. Ensure that when that burner is at max burn the power vent can handle it. That power vent is large enough to throw everything from one burner at it. Set your combustion dampers where you get a good fire and leave them there.

Let the boiler sit and run for at least four hours. Then let us know what the system is doing. Stop making changes to everything at the same time.

LET IT SETTLE AND CYCLE
DONT TOUCH ANYTHING ELSE

Let us know what happens after fours hours of running like this. Once it is set up properly for one burner then we can add the second utilizing exactly the same methods.

Exactly this!! Your fire and draft need to be set properly and at this point I do not believe they are. Read this and lets get back to the real issue

Running a power vent with the baro foiled over is an excellent way to get a hopper fire if you aren't careful. My neighbor proved it 2 years ago.

I suggest calling LL and having one of the guys walk you through the setup, step by step.

blrman07 wrote:Folks we are so far away from basic operation here it's painful. I have troubleshot boilers furnaces and stoves for the last 40+ years and when you get away from basics this type of stuff shows up. Everything is screaming at me that this is not equipment malfunction. Assume that this is a brand new installation and he needs to set everything up EXACTLY like it's a first time burn. Forget the flows right now, forget pipe size, forget BTU's etc etc etc. Gett out of the numbers and lets get to hand operation just like it was a single burner boiler sitting there. We need to set up the boiler so it can put out it's max capacity right where it's sitting, one section at a time.

Lets set it up like it is the very first burn and eliminate one system at a time. First make sure we have the proper draft while it's just sitting there. No fire, no coal, going through. Verify Draft and write down the draft numbers. Your boiler is rated at 220K. Your power vent is rated at 280K. ASSUMING everything is set up properly, there is no reason why your power vent can't handle everything the boiler can throw at it.

Swyman You said earlier that when you have your power vent at max the baro is wide open? Is this correct? If it is you are pulling air through the baro, not through the boiler. With the baro allowing max draw through it at any level of fire there is no way physically possible that you will get the draft through the firebox that it has to have.

Put the book down because your in the real world not the book world. With all the tinkering you have gotten away from the basics required for setting up a boiler with a power vent.

Pin your baro shut and foil your baro over so no air can get through it. You need to set the power vent speed so you get settings that the manufacturer calls for. Start your combustion blower and adjust your blower inlet so you get the number you want. THEN light off the one burner and adjust your power vent for that load. Don't touch the inlet damper!!!! You only adjust your inlet damper to get the correct FIRE. Ensure that when that burner is at max burn the power vent can handle it. That power vent is large enough to throw everything from one burner at it. Set your combustion dampers where you get a good fire and leave them there.

Let the boiler sit and run for at least four hours. Then let us know what the system is doing. Stop making changes to everything at the same time.

LET IT SETTLE AND CYCLE
DONT TOUCH ANYTHING ELSE

Let us know what happens after fours hours of running like this. Once it is set up properly for one burner then we can add the second utilizing exactly the same methods.

^^This^^ +1

I don't think he even read my post about setting up a power vent

Or the link with the power vent on the Keystoker...that would be quite similar

I don't think he's grasping the basic concepts, which makes it difficult to assess and understand what is happening, and choosing which step to take to adjust for it.

If he doesn't get the draft and fire right, the rest doesn't matter...yet

Rob R. wrote:Running a power vent with the baro foiled over is an excellent way to get a hopper fire if you aren't careful. My neighbor proved it 2 years ago.

I suggest calling LL and having one of the guys walk you through the setup, step by step.

This is why I suggested setting up the Power Vent with the baro pinned, just over the spec, then use the baro to dial it back just a tad.

That will allow the Baro to keep the draft there and prevent an overfire condition that could burn all the coal on the bed and up into the hopper