Dave in QCA
Joined on May 6, 2010
Last Post on May 17, 2013
@ February 5, 2013 5:34 PM in Another Look at Vapor VacuumThe Dunham Air Eliminiator, The Dunham Air Check, and any other device that does not have the capability to close on steam are all only for return pipe venting on a 2-Pipe system.
@ February 5, 2013 3:10 PM in Another Look at Vapor VacuumThere is a vent through a 1/2 pipe and a swing check valve, but no typical vent device such as a Hoffman 75 or Gorton 2.
The original Dunham system would have used and air eliminator and an air check or a swing check on their larger systems. The air eliminator had a float guarded against rising water in the returns due to pressure in the boiler. There was not protection against steam because unless a trap in the system fail, there is no steam in the return. If a trap fails, the system should not mask the condition, you want to see the steam.
This installation is guarded against rising water in the returns with a Vapor Stat to limit the boiler pressure.
@ February 5, 2013 12:21 PM in to convert cast iron to steamview in prewar condo NYCHere are a few images of radiators that are cleaned up and painted. Didn't sandblast them, just scraped and wire brushed, the painted with rustoleum metalic paint.
You need to be forwarned that the steel radiators that you are thinking about using will behave very differently than cast iron. The BTU will be less and once the steam has shut off the steel radiators will cool down VERY quickly. An advantage of cast iron is the way they continue to emit heat for an extended period of time. This will most likely result in your boiler being missmatched to your system and will cost a lot in fuel economy.
@ February 5, 2013 12:12 PM in marble tops on radsI knew that enclosures and shelves caused a reduction in the thermal efficiency of a radiator, but I do find this report VERY interesting. I am cutting and pasting the section of the conclusions that deal directly with the radiator and shield or enclosure. Surprisingly, the overall economy is actually improved by a properly designed sheilf or enclosure because of its effect in lowering the temperature at the ceiling and raising the temperature at or below the breathing level. That is to say, less steam condensed and less heat produced, but more heat and improved temperatures where they matter for the occupant's comfort. I am surprised!
Attaching a couple photos of an original heat shield at the Best Mansion.
Conclusions.-As a result of the investigation the following conclusions may be drawn:
(1) A reduction in steam condensing capacity of an enclosed radiator represents a sensible gain in steam economy if the reduction is accompanied by equally or more satisfactory air temperature conditions within the room.
(2) A reduction in steam condensing capacity of an enclosed radiator represents a sensible loss in steam economy if the reduction is accompanied by less satisfactory air temperature conditions within the room.
(3) More satisfactory air temperature conditions in the room are represented in general by higher temperatures of the air near the floor, higher mean temperatures of the air in the living zone, or below the breathing level, and lower temperatures of the air near the ceiling.
(4) The use of a properly designed radiator enclosure, or shield, results in a gain in steam economy, and equally or more satisfactory air temperature conditions in the room as compared with those obtained by the use of an unenclosed radiator.
(5) The use of an improperly designed radiator enclosure, or shield, results in unsatisfactory air temperature conditions in the room unless an amount of radiation in excess of that required for an unenclosed radiator is installed.
(6) A properly designed enclosure or shield should offer a minimum of resistance to the flow of air over the radiator under gravity head, and should protect the wall back of the radiator against the effect of direct radiation from the radiator. It should have the topof the opening in the face of the enclosure as high as possible, and permit free access of air over the lower half of the radiator, especially near the floor.
@ February 5, 2013 11:21 AM in Another Look at Vapor VacuumMy new boiler and venting system as been in operation for close to 2 months now. Here are my observations.
The system will pull a vacuum of 4-5" Hg on a 20 minutes steaming cycle and 5-6" Hg on a 30 minute steaming cycle.
Steaming seems to begin faster, steam travels down the main faster, and while there is a little bit of air venting each time, it is a VERY SMALL amount compared to a start when the system is completely filled with air.
I do not appear to be able to produce subatmospheric vapor in these conditions. I am guessing that I would need to put a vacuum pump on the return system and draw it down to a deeper vacuum... Experiments will follow!
While I thought that my system was very tight, I discovered a pinhole leak in one of the 2" end of mains that loops back to the boiler room. Repair will be soon. All of the radiator valves have been tightened up and do not appear to be leaking. I do have one radiator that has a crack in it. It is about 4" from the top and I'm sure it's leaking a bit. There may be leaks in other pipes, but hopefully not. All of the system risers are inside the calls. Given that they are inside the walls, they are also insulated, which helps the overall system.
Even If I get no additional benefit from vacuum, the fact that they system venting is through a check valve that does not allow the reentry of air when the burner shuts down does appear to reduce the burn time that is required to get the air out of the system. Since the flow of air in and out of the system is reduced, on could assume that oxygen corrosion and the formation of carbonic acid would also be reduced.
@ February 5, 2013 10:40 AM in Oversized Boiler?Congratulations on being able to resolve this correctly. The proof in the end is that your properly sized boiler is functioning the way it should.
@ February 2, 2013 5:48 PM in marble tops on radsThe effect that a slab of marble has on a radiator depends a lot on the design of the radiator. In the home that I live in, we have quite a few of those short 17" tall x 5 column "window" radiators. The castings come very close together, in fact so close that you can't get anything through from the front face to clean the dust bunnies out. If we were to put a slab of marble on these, it would pretty much close off all of the interior flue passages and would greatly restrict the radiator.
However, the one that I showed from over at the Best mansion, it is a simple 3 column radiator and there is ample spacing between the castings. When the radiator is hot, you can feel a huge draft, the same as what you'd expect to feel, above the front edge of the shelf slab. It seems that what normally would flow out of the top of the radiator is flowing out of the front top area of the radiator. Given that this little 52 sq ft radiator heats the room just fine, and its 17' x 30', I would say that the effect of a top shelf on this particular radiator is negligable.
Physically, I know that it would still have some effect. If the radiator was fully steamed and stayed that way continuously, and you measured the total heat output with the slab and without the slab, there would be some difference. However, in the real world, the radiators in this system usually only partially steam. The boiler cycles once per hour. By the time the boiler starts to run its next cycle, this radiator has cooled about the same as all of the rest of the radiators in the house. So... I would conclude the effect of the shelf on this radiator, given the way it operates in this house, has no impact at all. And so in answer to the question, how much difference does it make? It all depends.
@ February 2, 2013 5:17 PM in boiler lockout cover - OK to keep locked?The switch is there, painted red, so that the boiler can be turned off whether for servicing or in an emergency. Even though there is another switch, a person might encounter an emergency situation, see this switch, and then become flustered.
So, you have a switch that is supposed to be able to function, except if it needs to be locked out.
The lockout is to be used to lock the boiler in the off position, not in the on position.
Isn't the answer obvious?
@ February 2, 2013 5:08 PM in cleaning my burnersI hope it checks out OK. But, You GOTTA CHECK IT OUT!!!
@ February 2, 2013 5:06 PM in cleaning my burnersThis picture looks better. But, perhaps still a little bit yellow to the left side of the picture. Better be safe than sorry. Check out the flue passages. Its not that hard to open it up.
@ February 2, 2013 5:04 PM in cleaning my burnersZach, Everyone is alarmed when they see in your pictures, and I am too. I will add my two cents on this subject.
First, the picture of your dirty burner, with the red rusty crud all at the back half of the burner is not the way burners get dirty from normal use in a boiler that is good condition. Usually, the crud that will collect is darker in color and it will a fine grit that will collect uniformly along the length of the burner. Now, I cannot say that your boiler has a leak in it from only looking at this picture or your burner. But, a boiler that has a leak above the water line will produce a lot of red rusty colored crud in the immediate area of the hole. It will fall down through the flue passage and land on the burner. Were all of the burners like that? I would guess that they weren't, rather 2-4 burners is more likely.
Also, if your boiler has a leak, the crud will collect in the flue passages in the immediate area of the hole and will start to close up the flue. This will cause the flames to burn yellow because there is not enough draft to provide proper gas air mixtures. Even though you have cleaned the burner and the venturi areas are clean, etc., etc., if the flue passage is partially blocked, it will cause yellow flames and partial combustion, and a high CO mix in the combustion byproducts. If this is what is going on in your boiler... the next thing that will happen is this. The flue will get so blocked that the flames will begin to roll out of the combustion chamber and up in the cabinet area above the burners. I would guess there is wiring in there. It can catch on fire or melt. Melted wiring can short out and sometimes bypass your safety controls causing the boiler to fire continuously until someone discovers a disaster about to happen and shuts of the power.
So... DON'T WAIT UNTIL SPRING! Take the top off of your boiler now. Then unscrew and remove the flue collector cover and thorough examine the top of your block and the flue passages. You will probably find a bunch of red and white crusty build up in a few areas that are indicative of a hole in the block, just above the water line. Are you seeing an unusual amount of vapor coming out of the chimney when the boiler is firing????
I sympathise with your frustration with service people that do not know what their doing in regard to your steam system. But you gotta take this seriously. You may, (probably do) have a very serious situation and you seem to be blowing it off.
@ February 1, 2013 5:02 PM in Actual savings over steam heatingYou have the same basic Missunderstanding as I did, of the meaning of the Net I=B=R ratings for steam and water systems, how they are calculated, and what they mean. For many years I too was thought that the difference between the net ratings for steam and water represented a difference in efficiency. Of course, the net ratings do not mean that at all.
You need to do some homework.
@ February 1, 2013 4:30 PM in New Boiler at the Best MansionMark, I have taken some time both yesterday and today to make observations and notes through the course of several cycles.
Yesterday, arrived during off time. 26% cycle, 15F OD, Sensor 1, 72; 2, 70; 3, 72. End of main=192 4" vacuum at boiler
New cycle began, 26%, Low Fire Hold. OD and room temps unchanged. 3 minutes, boiler steams. 5 minutes, steam at end of main "steam established" sensor (located at last lateral takeoff from main) 8 minutes, crossover venting traps closed, boiler pressurre = 2 oz. 9 minutes = 4 oz. 11 min=6oz. 22:15 off
Today. 8:32AM boiler in off mode, cycle=49%. OD=2F, sensor 1=71, 2=70, 3=72.
8:45, boiler on. Low Fire Hold. 48% cycle, OD=2, sensor 1=71, 2=70, 3=72 vacuum=5 1/2"
2 mins, boiler begins to steam, vac=3". 3 mins, vac=2, 4 mins, vac=1 and steam arrives at steam established sensor. 4:20, steam sensor reaches 190F, heat cycle begins. 5 mins, pressure =0, begins to vent very slowly. 6 mins, crossover traps close, boiler press=0. 7 mins, slight venting. 8 mins, 4 oz press at boiler. 9 mins, 5oz. 10mins, 6 oz. 11 mins 6.25 oz. 12 mins, 6.75 oz. Pressure remains same until 34 minutes, boiler shuts off Rads have heated 62% of the way across.
9:51 Boiler Start, Burner control in AUTO mode, firing on HI. 47% cycle space sensors unchanged from previous cycle. 2:45 steam arrives at steam established sensor. 3:15, crossover traps close. 4, 6oz pressure. 5, 10.5 oz pressure, burner switches to LO fire. 7, pressure at 7oz, boiler switches to hi fire. 7:15, 10.5oz, switches back to LO fire. hi and lo repeats. 31:30, OFF
15 minutes after cycle, space temps up to 73, 71, and 72. Vac=6" Next cycle 25% to compensate for overshoot.
Put Burner control back at LO FIRE HOLD>
Sorry for this being so cryptic. Hope it makes sense.
@ February 1, 2013 3:14 PM in Actual savings over steam heatingI do not have a years worth of data on the new system, and I don't have utility bills for the year before I purchased the property. However, I was able to download the heating history, which tabulates the the main information from the bills.
The highest usage billing period in the year before I bought the property was for a period ending 01/25/2008. The number of days in the period was 37. The avg temperature was 24. Therms used was 1699. Most current billing period, ending 01/24/2013, total days were 36, average temperature was 24, Therms used was 1190. That's a 30% reduction. Also, consider that about 1200 sq ft of unheated attic space was added to the conditioned space, an increase of 17%. In doing so, 161 EDR was added to the heating system.
What did I do? I converted from Steam to Steam. The very well engineered vapor system was de-knuckleheaded. Traps and valves were serviced, Tekmar 790 was added, mains insulated, inlet orifices added, and finally, a good wet base boiler was installed in December 2012. Combustion efficiency was greatly improved, standby losses were greatly reduced. At the same time, comfort was increased. Even today, with a temperature of 3F outdoors, the building is a comfortable 71 + or - 1 degree F, throughtout. And, with the radiant effect of cast iron radiators, it feels warm. I have many tenants that have never lived with radiant steam heat, and they love it, saying that they've never lived in a building that is so comfortable.
Would a modcon heating system be more efficient? yes. How much? Probably 3-10%, tops. Does this make steam the least efficient way to heat my building? Don't hardly think so. Would there be a reasonable payback by converting the system to a modcon hot water? No.
Back when I was working as facilities manager in a health care facility, the CEO would approve about any energy improvement that had a payback of 3 years or less. If it was over 5 years, he'd never approve it because the money could make a better return somewhere else.
People in my neck of the woods who are looking for the best efficiency are installing ground source heat pumps, aka geothermal systems. Are they more efficient than a modcon system? Yes! Does that then make a modcon the least efficient way to heat a building? No! of course not! To say that because it's not the best, it must be the worst, would be sorta silly.
I do think that there are cases where a modcon conversion would be the way to go. But, there are many cases where it would be a very expensive proposition with a VERY long payback. In my own personal experience, most of the conversions that I've seen were poorly designed, poorly executed, cost a lot, and didn't save much money. Does that mean they all are like that? No. But, it affects my opinion on the matter. They don't always turn out the way they're supposed to. However, Henry, I have not seen even one of your projects so I can't and won't argue their merits. I will assume that the facts on your jobs are as you say.
Likewise, you don't know the details of my building and it might not be real accurate for you to proclaim that I can cut my costs to 1/2 or 1/3 by switching to a modcon.
Additionally, I'll make you a promise, I won't go into the ModCon room and say that all ModCon systems suck. That would do nothing but close minds and ears to information that might actually be helpful.
@ January 31, 2013 11:19 PM in Efficiency of Steam SystemOur friends at Tunstall have cage units that can slip back inside the old trap bodies. Makes repairs much easier than installing new traps.
@ January 31, 2013 4:06 PM in marble tops on radsProbably best to take the conversation off the wall. Click on my name and send me an email.
@ January 31, 2013 12:35 PM in marble tops on radsActually, I would say it's soapstone or slate. It has been on top of the radiator since the house was completed in 1910. This end of the living room was designed specifically for plants and this would have been a great place for them to set. Note the tile floor. The patch tiles are where piping came up for a fountain that also sat here.
I know that technically the slab reduced the amount of convection. But, when I stand in front of the radiator, there is a LOT of convection going on. More than anything, the slab seems to deflect the current into the room a bit instead for having the warm draft running straight up the front of the window.
Second and third shot are just to show the surrounding area.
@ January 31, 2013 8:14 AM in Restoration of my Dunham Air Eliminator!Ban, Nice job! It should work great!
@ January 30, 2013 9:33 PM in Need help buying TRVChris, glad to hear your TRVs are working out.
@ January 30, 2013 9:16 PM in New Boiler at the Best MansionI tried to run setbacks back in 2008, but had so many compaints that I gave it up. Too many different personal schedules in the building. Also, the huge amount of masonry and reinforced concrete in the structure tends to act as a huge heat sink, slowing the cool down, and the warm as well.
I will be at the building tomorrow and will time some cycles and make some notes. Today, I noted that while it was bout 26F outside, the cycles were ranging in the 28-30% area. As I recall, from the point the boiler started to fire until steam to to the end of the main took about 8 minutes. It is running one hour cycles, so at 28%, the heat on time was 17 minutes and the heat off time was 43 minutes. The radiators heated about 1/3 of the way, then began to cool over the remainder of the hour.
Tekmar also has an adjustment called "Boiler Design Percent". I believe that I have this set at 50 or 55%. This was necessary to prevent overheating.
@ January 30, 2013 5:26 PM in New Boiler at the Best MansionI think the distance would have been way to far for an atmospheric with a large flue size, but on this, the 8" forced draft works fine. Yes, the pipe is single wall. The chimney is about 45' tall and produces plenty of draft. The barametric damper is kept a little open in still weather and a LOT open when it's windy.
The original boiler sat in the same location, in fact it was much longer from firebox to back end. It must have been a fire tube boiler, probably brick set and two pass, which would have put the smoke pipe about where the steel support post is that is now supporting the original building header. Anyway, in that spot on the floor, instead of concrete it appears to be fireclay cement and I figure it is under the ash collection area.