The Best Heating System

Rod

Thanks for Sharing your Findings

Dave- Thank for the update on the orifices. Fascinating!  Having a one pipe steam system it makes me green with envy!

- Rod

Dave in QCA

Nothing wrong with that...

Nothing wrong with 1-pipe.  If I the building would have had a one-pipe system, venting adjustments, i.e., vent the mains fast and the radiators slow would have resolved most of the problems.  However, there is no way to vent a 2-pipe radiator slow and in this unusual situation where the suppies to the radiators are oversized, (probably the first 2-pipe installed in the area) it made for an unacceptable situation.  Nice thing about 2 pipe is that you can throttle the inlet valves if needed.  

Also, the orifices to create some amount of velocity noise, so the system is not quite as silent as it was before.

Dave in QCA

Orifice Fuel Savings Report!!

First, I am not sure when to let this old thread die, but it is a continuing saga and it seems like a good idea to just keep posting updates on the original thread.



Just got the first energy bill after running the system on newly instaled inlet orifices.  Keep in mind, that I first had thought that the 3rd floor was not getting enough steam, drilled out the orifices, only to find that once the temperatures got down into the 40s and stayed their for a time, that the 3rd floor overheated by about 8 degrees!  I restored all of the drilled out orifices except the one in the bathroom to the proper sizes.  Completely turned off the smaller of the two rads added to the old party room, now 3rd floor apt living room.  Temperatures are not all within 1 degree through out the building, but this was accomplished about a week ago.  The usuage on the current utility bill was from the time when I was overheating the 3rd floor.



Prior Year

Billing period, 31 days. Avg Temp, 47F. Usage/Day=26.52   Cost/Day=$18.76



This Year

Billing period, 31 days.  Avg Temp, 46F. Usage/Day=23.55   Cost/Day=$17.02



It is nice to see real savings!  I attribute it mostly to being able to have a lower setpoint (71) as a result of even temps throughout the building and not wasting energy overheating parts of the building.

crash2009

That is great news Dave

 It was, on average, colder this year, and you used less fuel to heat the place.  It is nice to see an instant return in $$$. 

Dave in QCA

Savings Report Update

Pulling this old thread up again.....



I just got the most recent gas bill which included most of February.  I thought I would post a graph and table showing the usage over the past 2 years.  There are a number of factors in the savings, not the least of which this has been a pretty mild winter. 

The factors that could possible be attributed to the savings are:

1. Orifices were installed which have produced very even steam distribution and very even building temperatures.  It is no longer necessary to overheat part of the building to maintain 69 in the cold parts of the building.  It is now 71 + or - 1F throughout.  

2. It has been a mild winter!

3. Much insulation was added above the 3rd floor ceilings.

4. Previously unheated space, a very large room, 720 sq ft with high ceilings was added to living space on the 3rd floor. To heat this, a radiator with 88 sq ft was added.  (This would have added to the heating load)



Here is the data!  

Steamhead

If you go here

ftp://ftp.cpc.ncep.noaa.gov/htdocs/products/analysis_monitoring/cdus/degree_days/archives/Heating%20degree%20Days/



you can correlate your gas usage with the number of degree-days for that period. This way you can express the building's usage as therms per degree-day.... kind of like miles per gallon on a vehicle.

Dave in QCA

Ridin' this old dead horse around the barn yet another time...

This is a Reply and update to BoilerPro's reply to this old thread on Jan 30, 2011.   It reads as follows...



Fuel bills et el.

I worked in a home with very similar size and construction as yours and replaced a very similar boiler (Utica version of yours at 700,000 input), with two 200,000 input slantfin gas fired Intrepids that are stage fired. Fuel bills are running about 60% of yours now. I bet alot of your high fuel usage is the boiler. I've combustion tested many of those units and their firing efficiency is very poor.....a fairly high level of excess air and high exhaust temps. The newest models are slightly better due to better control of combustion air, but still are poor. They also have pretty high amounts of waste due to the huge uninsulated flue collector, which gives artificially lower exhaust temps when combustion testing. I suspect even at full fire under the best of conditions, you are getting at best about 65 to 70% firing efficiency and, if properly sized, about 10% lower seasonal efficiency due to standby losses. They do make good steam at those smaller sizes due to the big 4 inch steam dome. I imagine at that reduced firing rate, your firing efficiency is in the 55 to 60% range......Ouch!

Sometimes you just got to work with what you got.

[End of Quote]



My Reply



I am currently getting ready to finalize a contract to replace the old Pennco boiler with a Weil-McLain 680 with a Riello 2-stage burner.  In looking at what the firing rates for the new burner should be, I have been going through the old numbers.  Since the system is orificed, the radiator consumption of steam is easy to determine at the design pressure of 8 oz.  Calculating backwards with the assumption that there is 10% piping loss and the fact that it currently takes a firing rate of 600,000 BTU to maintain 8 oz. pressure in the mains, the current combustion efficiency is about 56%.   Once again, Dave Bunnell nails it!



  So, after the new boiler is adjusted and running, it should have the same output of steam with firing rate of 400,000 BTU, or 34% decreasing in firing rate.  However, I may have it set up to fire at roughly 300-350K to take advantage of slower and longer steaming cycles.  300K BTU firing rate is what is needed (by calculations) to keep the rads heated to 70% of their capacity.



Also, I will time the current boiler to see how long it takes to make steam after the boiler has been off for 55 minutes and compare that to the same test on the new boiler.  This will give an indication of the amount of heat that is not going up the chimney or being radiated into the boiler room.



As I am getting close to the actual removal of the old boiler, I am beginning to find it quite funny as to just how many serious piping flaws there are in the close boiler piping.  It is another great example of what NOT to do!  Of course, that is something that is not in short supply on this wall! 

Enreynolds

Vapor/Vac?

Dave, are you still planning to retrofit to allow dropping into vacuum?  I am finishing an install in my house using a Burnam Megasteam with an ez-gas burner, minitube system, all set up to allow vacuum.  I have also installed a honeywell high/low/off valve in the gas train and I am fabricating the parts to actuate the air damper on the burner.  I have a few more baseboards to install still, and then I will be off to the races.  Good luck with your install.

Eric

vaporvac

Why WM680 w/Riello 2-stage burner?

I'm reading your most  recent posts with interest and am wondering what influenced your decision to go with the single WM680 vs.the modular SF approach as mention by Boilerpro. I believe the WM  is also wet-based boiler.  I have less EDR than you, but still quite a bit (1,460) and had not really considered a single 2-stage burner. Since you have mentioned returning your system to a run on a vacuum as mine was designed, I always look to see what you are doing with yours and why. Your posts are always so explicit. Thank you. Colleen

Dave in QCA

Yes,

Still planning on restoring to vacuum operation.  I'll post results when we get there.

Dave in QCA

WM 680

Colleen,

Here is a Cut and paste from another post.



Thinking, perhaps overthinking it!



I have strongly considered using two small boilers set up in a modular staged setup. Boiler Pro has done those and shared his experiences on a job quite similar to mine. He also mentioned, as I recall, that he had considered using one larger boiler with a modulating or 2-stage burner, but in the end opted for two smaller slant fin boilers (TR-40 as I recall.). Redundancy and having a backup were a factor in the choice. He set up the control with a 2-stage thermostat. The second stage boiler does not run unless the first stage can not keep up with the load. Even distribution was a little bit of a problem, but it was resolved by pinching down the inlet valves with future plans to install orifices. I am not sure I remember this correctly, but as I recall there might have been some problems because of very low water content in the boiler and the need for a reservoir on the gravity return setup. My apologies Dave, if I have any of this wrong.



So, I have thought and considered, looked at the situation from all sides and here is where I have landed (at least for the moment) I appreciate the value of having a backup boiler, I ran a hospital plant for 17 years, everything has a back up! However, while there is benefit, there is also a drawback as you have twice the chance for equipment failure-- essentially you have 2 boilers to maintain instead of one. The following are factors I have considered: (please do not take any remark that follows as a criticism of the Slantfin models, that is not my intent, I'm just trying to draw comparisons.)



1 The Weil-Mclain 580 (and the Burnham V-904, the other option) both have essentially the same efficiency ratings as the Intrepid.



2 Also, both the boilers have a significantly higher water content than the Slantfin Models. That water content is the same as my current old Pennco boiler and the water level only drops about one inch before condensate begins to return, where it remains stable until the boiler shuts off. In about ten minutes the water level is back where it started. I think that is stable enough. So, it would stand to reason that the WM 580 water content would be adequate to operate without having to install a reservoir to increase the water content.



3 I am controlling the system with a Tekmar 179. It does not have the ability to control 2 stage firing. So, if I opted for the modular approach, I suppose I could lock out one of the boilers based on outdoor temp but would lose the built in automatic redundancy. I could control off of pressure with an additional vaporstat, as I would with a 2 stage burner, but in this case the lag boiler would fire on every cycle and that is not desirable and would negate the efficiencies gained by staging. I suppose there could be a combination of a pressure control and outdoor temperature lockout, so that the second stage would never fire unless the outdoor temperature was say, less than 20F, and then it would be controlled off of the second stage vapor stat. This same approach could also be used on a 2-stage burner.



4 I am already concerned about the sound level, but figure I can tolerate the Riello burner with its acoustic cover. However, not so sure about the sound level of having two of those running at the same time.



So, the unknown to me, is the combustion efficiency while firing at 60%. It would seem to me that if the excess air is tightly controlled, the boiler would be equally as efficient at 60% as it is at 100%. I note that the Intrepid models such as the TR-50H, (high efficiency model) is simply the TR-50 with a firing rate 10% lower than the regular model. This is a case where turning down the fire increases the efficiency.

I'm hoping that someone out there has done burner tuneups and checked efficiency either on the 2 stage burner or any other scenario where the boiler was being fired significantly lower than than design maximum firing rate.



As proposals have come in on the boiler replacement, it turns out that WM will not support the 2-stage burner on the 580 boiler, only on the 680 boiler.  So, that is what we are no considering.  The 680 is factory rated for firing rates up to 787,000 BTU.  I am planning on a hi fire rate of 600,000 BTU and a low fire rate of 350,000-400,000 BTU.  It is my understanding that on a power burner application, where combustion excess air is tightly controlled, that combustion efficiencies are not comprimised by firing below the full rated capacity of the boiler.  In fact, in portios of the range, the efficiency may actually be better than the efficiency levels obtained while firing at 100% rated capacity.



Another factor that I have not mention is that the current connected EDR is 1368 sq ft.  There is an adjacent building that has been removed from the steam system that I would like to be able to reconnect in the future. Also, there are a couple of indirect rad that I would like to put back into service too.  If this is done, the total EDR is a little over 2000.  The large boiler would handle all of this with ease.  A 2 stage burner would also effectively deal with fluctuating load caused by occupants turning off some of the rads.

Dave in QCA

New Boiler Install starts on Monday

Hi friends, I thought I would post a question out here for all of you that have followed this VERY VERY long tread, and others who may have joined more recently. 



The new boiler install will be beginning in a few days, and my question to you all is whether I should add that onto the end of this thread, or start a new thread altogether.  This thing is getting just a bit long and perhaps that makes it difficult to read and follow.   If I do start a new thead on the boiler install, I would include a link back to the original thread.



Your thoughts and comments would be appreciated.  If you want to avoid clogging up the thread with poll answers, feel free to send me a message directly.  Thanks!

nicholas bonham-carter

Yes start a new thread w/link to orig

Keep the house pictures, and more in the new thread.--NBC

crash2009

Hi Dave

 for those of us that have subscribed to this thread, it probably doesn't matter what length the thread is because the subscription takes us to the end of the page anyway.



For those who have not ever subscribed, they might be reluctant to comment before reading the entire thread.  This might reduce the amount, or quality, of comments, from those who are to busy to read for a half hour to get to the question.



Tough call Dave, I could go either way.  If you do start a new one, make a link from this one to the new one.  and also from the new one to the old one.  That way your covered either way. 

Dave in QCA

Getting all of the Good Out of it!

I will be starting a new thread on the boiler replacement project that is scheduled to begin on Monday, 11/26/12.  That boiler replacement has much to do with the fact that old boiler is WAY oversized, very inneficient, and at 37 years old likely has not much life left in it.  The permit is still hanging in the boiler room and it is dated July 1975.  I thought it would be better to replace it as a planned event than an emergency!



But there is one last post that I think belongs on this thread.  Last night while over at the building to check on temperatures, etc., the boiler came on and I observed it firing.  After the vents closed, I could still some barely audible hissing sound.  I couln't tell where it was coming from, but it sounded like the boiler.  I walked around, listened from all angles, then leaned over and listened from below the draft diverters at the back of the boiler.  One of the two diverters was quiet, but the other - I could definitely hear what sounded like a steam hissing sound coming from the flues of the boiler.



Today, I went back over and removed the flue access cover and low and behold, there is a new crack in the stop of one of the sections, second from the right side, furthest from the feedwater side.  There is beginning to be the characteristing rot showing on the sides, just below the top.   With new the new boiler project beginning in two days, I would say that I got all of the good out of this boiler that could be and the replacement was actually perfectly scheduled.   I hate to see a boiler rust out, but actually, I'm just a little bit happy about the way this all worked out!

SWEI

Talk about timing

perfect timing, that is.  Look forward to seeing the new install as it progresses.

Dave in QCA

Last Post

The new boiler has arrived!!!!  Work has commenced. 

Because of the length of this post, I will not be adding anything more. 



The next chapter can be viewed at http://www.heatinghelp.com/forum-thread/143629/New-Boiler-at-the-Best-Mansion 



Thanks to everyone for their help, advice, wisdom, and most off all, the encouragement.