Boiler Size Feedback

KellyM

Thanks for the help. I will post pictures this weekend when my wife loads the software on to my computer. The existing vent is attached by a one inch pipe and sits above the Moline air relief valve. At some time it appears that the vacuum valve was removed and replaced with a bell vent. The vent is a very old Trane. I was checking the valve and noticed that both the valve and the condenser run on the basement ceiling were not hot. (Unless I turn the thermostat way up the, the system is short cycling.) I decided to open up the air relief valve and found it filled with water. I cleaned out the water and debris in the air relief valve and started the system up and could feel a steady draft of air through the air relief valve. I replaced the top and the vent and the system continues to short cycle. I will add the two Gortons to the system. I was going to use one in place of the old Trane. There are four holes in the top of the Trane and I don't feel any air movement out them. Is this what you would do? Would you put the second Gorton #2 on the steam main, or do you have another suggestion.

KellyM

Boiler size feedback

I was trying to calculate whether this boiler (Burnham 5008b) is oversized/undersized or right sized, and if so by how much. I calculated the radiation square footage for the home at 1,276 square feet. The system is a Moline Vapor system circa 1915, so I used the 1.5 factor and then multiplied this by 240. I got 459,360 BTUs for the boiler size. If a 1.33 (recommended by Burnham) factor is used then the product is 407,299 BTUs. The average of these calculations is about 433,000 BTUs. The boiler has an AGA rating of 436,800, an I=B=R of 1,367 sq ft and 328,000 MBH. I think based on the calculations that the boiler is about the right size for this system and the iron attached to it, but I am looking for some thoughts from others who have worked on similar systems.

Also, this system has been short cycling and I am trying to address every potential problem. I know it needs to have the pressuretrol replaced by a vaporstat. However, I am also trying to figure out if the original air relief valve, vacuum valve and ejector are working properly. Any suggestions on how to analyze these would be appreciated.

Unknown

Sure, a quick check...

Start the boiler, and go to the vent. The vent should become steam-hot before the boiler shuts off by the pressure control. If the boiler goes off and on while the vent is cold, you need more vent capacity.

Noel

KellyM

Boiler Size/Vent

Is there one vent or another that works better on a vapor system? Gorton, Hoffman, etc

Boilerpro_3

Go with a couple of big Gortons

They outvent anything I've ever seen. This is especially important since there is only one vent on a Moline system. I worked on one of those systems a couple years ago and we downsized the boiler considerably. Moline systems were desigend to only heat about 80% of the radiator, so your calculation should include this correction. In addition, I believe...though I am in a definte minority on this subject, that if you have upgraded insulation, windows etc, and balacne the radiators at the valves, you can further downsize the boiler because the boiler no longer can see the excess radiation because the partially closed valves meter the amount of steam necessary to heat each space. I did this with the system I worked on to a certain extant and the system heats wonderfully now and fuel usage has dropped dramatically.

Biolerpro

KellyM

Boiler/Venting

The existing boiler was purchased in 1994 and seems to operate fine. If I adjust my heating calculation by the 80% factor you suggest then the boiler may be oversized by as much as 25%. To downsize the boiler I have two options. The first is to order new smaller orifices from the manufacturer. This should downsize the boiler by 10 to 20 percent max, or I can plug 4 burners on the gas manifold at the boiler. The first is suggested by the manufacturer and the second is the easiest. Do you have any thoughts on how much you would reduce the boiler capacity and which of these two methods you would use?

Boilerpro_3

Boiler Downsizing

> The existing boiler was purchased in 1994 and

> seems to operate fine. If I adjust my heating

> calculation by the 80% factor you suggest then

> the boiler may be oversized by as much as 25%.

> To downsize the boiler I have two options. The

> first is to order new smaller orifices from the

> manufacturer. This should downsize the boiler by

> 10 to 20 percent max, or I can plug 4 burners on

> the gas manifold at the boiler. The first is

> suggested by the manufacturer and the second is

> the easiest. Do you have any thoughts on how

> much you would reduce the boiler capacity and

> which of these two methods you would use?



Definitely go according to the manufacturer's instructions. I would calculate the actual heat loss of the structure before doing anything yet with the boiler capacity. To this I would add the standard pick up factor for your present radiation, about 1300 EDR times 1.33. This will give you a rough minimum size to work towards.
These vapor systems are quite different from steam systems, and probably can be balanced to use a boiler that may only heat 60% of each radiator if thats all you need to heat the home. We are stepping into new territory here, but I have seen it work even in one pipe steam. Since each supply valve is acting as a metering orifice, the pressure the system operates at is related to how much of each radiator gets heated

Boilerpro_3

Boiler Downsizing

Definitely go according to the manufacturer's instructions. I would calculate the actual heat loss of the structure before doing anything yet with the boiler capacity. To this I would add the standard pick up factor for your present radiation, about 1300 EDR times 1.33. This will give you a rough minimum size to work towards.
These vapor systems are quite different from steam systems, and probably can be balanced to use a boiler that may only heat 60% of each radiator if thats all you need to heat the home. We are stepping into new territory here, but I have seen it work even in one pipe steam. Since each supply valve is acting as a metering orifice, the pressure the system operates at is related to how much of each radiator gets heated. Also if you decrease the orfice size (close the valve partially), then at a given vapor pressure, less of the radiator will heat.

So let's say the attic has been insulated, reducing the heat load considerably for the second floor rooms, but not at all for the first. If the thermostat is on the first floor, it will operate the system at adequete pressure to heat the first floor, however, this means the second floor will overheat. If you close down the valves on the second floor rads about 20 to 30 %, typically the second floor will come into balance with the first floor since less steam is being metered into the rads at the pressure that is needed to heat the first floor rads. Now, the system has shrunk in size, because the boiler no longer can see the 20 to 30% of each radiator on the second floor. I would downsize the boiler to compensate for this reduction in size, however, the piping is still there so the Pick up factor amount should stay the same.

If you have a two stage gas valve on your boiler, you may be able to just run on the first stage. This is usually only 50 to 60 % of the peak capacity, so check you heat loss calculation, not radiation load. I'd discuss whether this can be done with your heating contractor and Burnham. If it can be done, then balance the system so its heats evenly and see how it works.

The system should not operate at more than 8 Ounces of pressure. If you control the system pressure with a vaporstat below 8 ounces, and your ejector and condensor pipe or radiator is still intact, you don't even need a vent on the end of the condensor because steam should never get to it. If you can post some pictures of what your working with it always helps. And keep everyone here posted on what your doing. Moline systems are one of the most elegant heating systems out there and are a thing of beauty and simplicity when working properly.


Boilerpro... just an hour from Moline, IL, home of the Moline system.