Dave in QCA
Joined on May 6, 2010
Last Post on June 10, 2013
@ June 10, 2013 10:29 PM in Downsizing boilerI installed a WM 680 last December. It is firing on low fire at about 390 BTU, or pretty close to 50%. The reason for the oversizing has to do with future plans to restore the old garage and chaufferer's quarters back to the steam system. But, for the time being, firing about about 50-60% the boiler is perfomering exceptionally well! Running about 30% less than the 1975 Pennco that it replaced.
@ May 27, 2013 11:42 PM in TwinBoiler SchematicColleen, This is looking pretty good but I have a couple comments. Regarding the condensate tank, I think you mean the reservoir? You won't know whether you will need that until you operate the system and see how slow you condensate comes back from the system and whether it causes a drop in your boiler water to the level that more water must be added, that eventually causes the boiler to be flooded when all of the water finally returns.
Regarding the piping, I think you have got this very close, and if you did the drawing.... I am impressed indeed! The problem that I see is that when looking at this drawing, and you are view the boilers from the back, each boiler has 2 risers, a header and an equalizer. This is all good. Then, each boiler has a steam supply the goes up and then drops into a pipe that I'll call the building header. This head drips down and connects to the return of the boiler on the left. This will cause the left boiler to over fill over time. I don't seen any piping that will allow the water level of the boilers to equalize. It seems to me that the return piping of the left boiler should continue on over to the right boiler, so as to tie them both together.
I'm sure one of the pros, especially Dave Bunnell will jump in and comment on this if I am wrong.
On a few other notes, I owe you a few emails and hope to catch up soon when I am back home at my own computer.
@ May 17, 2013 8:10 AM in Rusty bolts on the tankless water heating blankBack in 1985, I purchased a fine old home that had an H series Weil-McLain hot water boiler that had been installed in 1965. I had the system drained for the summer to replace numerous leaking radiator valves and to install some zone valves. A few months later when I went to fill the system, I found water leaking out of the boiler. Upon removing the cabinet, I found that the indirect heater blank plate was leaking around the gasket. I suppose it dried out while I had the system empty and then when I refilled it, it started leaking.
Anyway, being unafraid to tack the problem, I started to remove the bolts. To my horror, over half of them broke off, just about flush with the boiler casting. I tried drilling and using easy outs, all to no avail! I was beginning to think that I might be buying a new boiler. But.... the solution came from a very competent welder. The old trick of their trade is to weld a nut onto the end of the broken bold. And yes, they do that through the hole in the center of the nut and there does not have to be much, if any, of that bold protruding from the casting. The heating and cooling of the broken bolt loosens it from the cast iron. Then, as I recall, he used an impact wrench set on very low to remove the nut and broken bolts. All in all, it took him less than an hour, including cleaning out the threads with a tap.
He also made me a new blank plate out of plate steel. I got a sheet of red rubber gasket material and cut the gasket myself. I got the thick stuff because of the somewhat damaged face on the boiler casting. I put the thing all back together and it worked perfectly. The boiler continued to run well until a subsequent owner replaced the boiler sometime around 2004 because it "looked" old.
Good luck on your project.
@ April 26, 2013 4:14 PM in General Electric Air ConditionerDo you perhaps have the blueprints? Usually, if the heating system was part of the design, the radiation would all be noted in sq ft EDR. If they did that for the radiation, they would also have done that for the air handler. Just a thought worth looking into.
@ April 22, 2013 4:30 PM in A Steam Odyssey (Part 2): Midco Low-NOx BurnerMark, I am somewhat at a loss for words. This is an excellent groundbreaking project! The first application of the new Midco that we have seen! It seems to be everything that everyone has been anticipating. And, your AMAZING modulating, weather based control panel.
@ April 22, 2013 4:25 PM in A Steam Odyssey (Part 2): Midco Low-NOx BurnerBoiler Pro, aka The Steam Whisperer also did another article on 2 pipe system. Same ideas as the first paper, but he was proposing the use of orifices to provide even distribution instead of the "slow" vents proposed for 1-pipe.
I can attest that it has worked for me on my 2 pipe system. I fire at 75% of the normal recommended rate for the connected EDR. It works very smooth.
@ April 19, 2013 7:53 AM in A Steam Odyssey: Midco Low-NOx Burner Oil to Gas Conversion ProjectExcellent job on correcting the piping! How about some pictures of that new mysterious burner? I'd be very interested to know how you set it up and how you're controlling it.
@ April 16, 2013 10:12 AM in Venting risers after the supply valve?I think you will likely see great improvement when you at venting to your mains.
However, in direct answer to your question, I do believe that I have seen a few threads where folks have done exactly what you're proposing and that it was successful.
@ April 16, 2013 9:28 AM in Venting risers after the supply valve?I'm in complete agreement with NBC. Address your main venting first. Keep your main vents on the mains, not the radiators. If you remove old insulation make sure you replace it with new. If you do not have connections for vent, you can have a welder come out an install a "thread-o-let" on your main. It is probably the easiest and cheapest option.
Remember, vent your mains fast and your radiators slow, very slow. Once you have completed all of the above you can see if you still have any balance problems. If you do, then you could proceed to venting that riser and/or increasing the venting on the slow radiator.
@ April 16, 2013 9:16 AM in CondensateTank...Why?Colleen, I just wanted to reiterate what has been said before. Your new system with its two separate boilers, set up in a staged configuration is by definition, a 2-stage system. Lo = 1 boiler, Hi = 2 boilers. This will give you a LOT of control. In fact, more control than probably 98% of residential systems.
I can certainly relate that you want the system to be the best that it can be. Infinitely variable firing would be a great thing, but also a challenge to regulate with off the shelf components. Someday, somebody other than yourself will be called to service your system. You want to keep in mind that making a system that is unnecessarily complicated may not a good idea. I worked for a CEO a long time ago who often repeated a mantra "KISS!" or, "keep it simple, stupid." HA!
Pressure is one way to control your two, staged boilers. However, keep in mind that upon EVERY call for heat from your thermostat, they will both fire until a "set" pressure is established, at which point one boiler will drop out. During a long firing cycle, the lag boiler may start and stop several times to maintain that pressure. Keep in mind that maintaining that pressure probably has little to do with a varying heat load. A varying heat load results from changing outdoor temperature. Following that thought, one possibility, but not necessarily the best or the most simple, you could install an outdoor stat that would lock out one boiler when the out door temperature is above a certain point. Another option, and I think it is the best, because of its simplicity and the fact that it will allow the 2-stage system to respond directly to the heat demand in the space, is a 2-stage thermostat. This is exactly how TSW set up a pair of Slant-fins he installed in a large old home. I am trying to recall what he said, but I am thinking it might have also been a Trane system. It was not an orificed system and at first was a little prone to imbalance when firing on one boiler. But, this was easily remedied by partially closing all of the inlet valves, thus simulating to a small degree, the operating of an orificed system.
Two-stage thermostats are not a complicated thing. I think that the highly favored Honeywell Vision Pro is available with 2-stage heat control. The way I look at it, TSW has probably considered every possible control combination that could exist and he opted for simplicity with a 2-stage thermostat. There must be a reason.
@ April 14, 2013 10:02 PM in CondensateTank...Why?Colleen, Weil-McLain offers a design for a condensate reserve tank, for exactly the same reasons that you may need one. That is the water volume in the boiler is small compared to the time that it may take for the condensate to return on a big old cast iron heating system. It shows how it is connected and the location relative to the water line. That is a critical point.
Some boiler feed tanks are set up with feed pumps for the boilers and also offer the capability to drive off volatile gasses such as O2 and CO2, thus helping to protect the boiler. The plant that I managed many years ago had a large deareator tank as the feed tank. I performed an important function on a process steam application, but also consumed a fair amount of energy in doing so. Such systems are generally not used on heating systems and pretty much never used on a residential system.
Click on this link and go to page 19, figure 20.
@ April 14, 2013 9:51 PM in Drop Header:Which way to Go?Thanks for the details. I was beginning to worry about the water line, but your new water line will be fine, especially when you have the boilers setting on a concrete pad that will probably be about 4" thick. The new water line will be about the same as the old and well above those horizontal return pipes.
I am surprised at how tiny those Slantfin boilers are! They will run efficiently!
@ April 14, 2013 11:00 AM in Drop Header:Which way to Go?Great to see the pictures of the boiler room. Can you take more?
Also, I am wondering about 2 things. What is the elevation above the floor, of the horizontal return piping located in the area below your return trap? And, what are the return pipes that we see that drop and connect to that pipe? Are they condensate returns on your 2-pipe? Or, are they end of steam main drips?
I was just thinking about the earlier questions about wet/dry returns and the new boiler water line.
@ April 13, 2013 3:06 PM in Drop Header:Which way to Go?Follow the advice of the Steam Whisperer.
@ April 13, 2013 2:55 PM in A Steam Odyssey: Midco Low-NOx Burner Oil to Gas Conversion ProjectI offered the possibility of modulating the effective total EDR by using orifices and then varying the main pressure in answer to your inquiry on how that might be done. But, I do not operate my system in that manner. On mine, the orifices are sized for 8 oz main pressure and the boiler controls are setup to maintain that. Actually, the firing rate has also been fine tuned to maintain 8 oz in the mains.
My reason for installing orifices was because of a distribution and balance issue. During partial steaming cycles, which are the norm about 80% of the time in our building, some radiators fully heated and others stayed cold. Yes, this could have been resolved by installing TRVs on all of the radiators. But, orifice plates were another way to skin that cat, and at a fraction of the cost. It has taken a bit of time and the readjustments would have become quite costly if I was hiring a contractor to do all of the work. But as a retired fellow who in my early working days used to get his hands dirty working as a maintenance mechanic in a hospital, it was well within my abilities to tackle. The building is now fine tuned and has an incredibly even temperature throughout.
Yes, in regard to efficiency, operating at a modulating output to match the load does yeild improvements in overall efficiency. Studies of the savings of high turndown burners tend to account for those savings mostly because the pre and post fire purge cycles are reduced or eliminated and those are inherently wasteful.
Overall system efficiency is also greatly affected by the systems performance in putting the heat where it is needed and not putting where it is not needed. So, things like pipe insulation in basement areas and in-wall risers become very important. Also, minimizing overheating of spaces greatly improves efficiency. Reducing the occurance of overheating is affected by providing a comfortable space at the lowest possible temperature. Local code requires 70F in apartments and I find that I get no complaints from tenants at that temperature. However, if the space fluctuates from 68-71, I will get complaints that is is cold some of the time. If my system was operating with a 3 degree swing, I would have to turn up the heat to the point that the swing would be 70-73 F. And, for every degree above 70F that the space is heated to, it represents a loss in efficiency and an increase in cost. Thus, in this case, added comfort as a result of maintaining constant even temperatures translates to added efficiency and reduced cost.
@ April 13, 2013 1:57 PM in A Steam Odyssey: Midco Low-NOx Burner Oil to Gas Conversion ProjectIt is possible to vary the effective EDR or a radiator by throttling the amount of steam that it receives. In a 2-pipe system, this can be done by using TRV valves of course. The total EDR of a system may also be affected if some of the radiators are turned off. Thus, the firing rate of the boiler would have to vary if you were trying to maintain a constant pressure in the mains and boiler.
Another way in which you can effectively modulate the entire system is through the use of inlet orifices on a 2-pipe system. For example, if you have an orifice that is approximately 0.25", it will pass enough steam at 2 psi to nearly heat a radiator of approximately 92 EDR. At a pressure of 1 psi, the same orifice will pass enough steam sufficient to heat about 65 EDR, or about a 1/3 reduction. At 8 oz of pressure it will pass enough steam to heat 45 EDR, or 50% of the steam flow that existed when running at 2 psi.
Thus, if you are desiring to run a boiler in a continuous firing condition, but want to vary the capacity or effective EDR of the system, you could accomplish that with an orificed system and modulate the pressure in the mains.
In all practicality, I would have to say from the observations of my orificed system, set up for 8 oz. and controlled by a Tekmar 279, that in mild weather some of the radiators only get mildly warm on the first radiator section. From the time steam reaches the end of the main and pressure in the main begins to build, the cycle may end before the main even reaches 8 oz. I think it would be very difficult to establish a continuous low pressure that would not overheat the building at moderate outdoor temperatures. I also have to report that when set up for 1 cycle per hour, with cast iron radiators, inlet orifices, and Tekmar control, the space maintains a very even temperature. Most of the time, the sensors do not indicate that there is any fluctuation in the room temperature at all, reading a constant 70F. That causes me to wonder how much tighter the control could get.
@ April 12, 2013 11:21 AM in Radiators as ArtDan, you really do watch this thing!
Well, a very rough estimate with the assumption that the cube of radiator is solid and with no hollow space in the middle. And, assuming that the stacked manner would not reduce the effective EDR, which it would. My very rough visual measurement is about 4000 EDR or 960,000 BTU output.
What's your guess Dan?
@ April 12, 2013 11:07 AM in Diagnosing leaking pipe - condensate vs supplyOk my theory was all wrong. Aparently the leak is slow enough that it may not leak enough air to get the steam up to the pipe and/or the condensate issue that you have suggested.
My old system was also a very early Dunham type system and as in their early drawings, they showed both the supply and the return connections at the bottom of the radiator. The supplies are a bit on the large size, although not as large as on a 1-pipe system. The returns, (most of them) are connected through an eccentric bushing. The eccentric bushing is abosolutly necessary to drain the condensate when the supply is also at the bottom. If you have a regular bushing, then ALL of the condensate will exit back out the supply pipe. Of course, even if you have an eccentric bushing and the pitch is not correct, as you have pointed out, the condensate will flow back out the supply pipe.
@ April 12, 2013 10:11 AM in Radiators as ArtOk, most of us who tend to old steam systems come to appreciate the heating system and all of its components, especially the radiators, as objects of beauty and amazement.
Here is another take on the beauty of old steam radiators! I can't help but try to imagine the total weight of the collection..... of the salvage value....... and even the total EDR! WOW!
Click on link and scroll down.
@ April 12, 2013 10:03 AM in A Steam Odyssey: Midco Low-NOx Burner Oil to Gas Conversion ProjectIf you want to install a TRV on the supply to a radiator, it must be altered so that it operates as a two pipe system. There are two options for the piping.
One, connect a new outlet on the radiator with a steam trap connected to a vented return line and remove the vent from the radiator. This would be the modern trapped 2-pipe system.
Second option is to leave the vent in place and run a new return on the radiator and run it down to a wet return line with the connection below the NWL of the boiler. This would be the very old vented 2-pipe system.
@ April 12, 2013 9:56 AM in A Steam Odyssey: Midco Low-NOx Burner Oil to Gas Conversion ProjectIf you installed a steam trap in the location you have shown a water seal trap, the flow would be backward through the trap. That is, first air in the steam piping would flow into the radiator from the steam riser. The, when steam arrived, the trap would close, although not real effectively because the pressure would be trying to push the trap open and the element that makes it close would be above where the steam is. At any rate, any time the trap opened, the differential pressure would cause the flow to be moving from the steam main into the radiator, at least until there was enough condensate pooled in the bottom of the radiator to cool the trap, then it would open. steam would bubble and bang through the trap while condensate was also trying to flow out.
In short, to work properly a steam trap must be connected to a pipe which is connected to atmosphere.
@ April 12, 2013 9:49 AM in Old videoThanks for the videos! What a great indicator that your boiler is perfectly sized for your system! It could not be much better.