Most efficient steam system on the planet?

[Deleted User]

I've been trying to tune up my steam system with ancient 1918 boiler. I spent $400 on gas last month and that is a record, and it hasn't been that cold. It generally runs about 5 minutes on, 10 minutes off under normal winter conditions.



I replaced the vents with Gorton #2, the old vents seemed to be sealed closed. Then, not knowing what was going on with pressure, I just added a low pressure gauge. Well that took me about two hours because I had to unwire the pressuretrol and rewiring it was a PITA. So the house got kind of cold. When I fired back up, the boiler ran for about 45 minutes. Never saw that before.



Guess what the pressure got up to? Zero. 0.0. If low pressure is the holy grail, as everyone says on this forum, I must have the best system on Earth! But that extremely low pressure is consistent with the test I did with the vents off; the air and steam seemed to be very lazy at the vent locations, and the rad vents just have an extremely gently air flow.



Then it shut off. Some of the radiators had gotten much hotter than usual, which was nice to see. I discovered that with the pressuretrol cover off I can keep an eye on that big nasty mercury switch to see if it is shutting off on pressure (it has always been set at 2 psi for cut-in and +4 differential for cut-off). No, it never cuts off I think.



Then I checked the combination auto-water feed and low-water-cutoff. Flushing it while the boiler was running, it clearly starts adding water before it cuts the boiler off. So no issues there.



That leaves only the thermostat as a cause for the frequent cycles it normally goes through. I took the cover off and saw something weird there. What is that adjustment? It is set at about 0.6, whatever that is.



If I need a new thermostat, what kind should I get? I suspect my boiler is operating on extremely low voltage, as I just get erratic readings with a voltmeter at the transformer terminals (see picture), 0.1 V, 50 mV or something. Do digital thermostats operate with that kind of voltage?

ChrisJ

Anticipator

That is the anticipator. It's essentially a heater that heats the thermostat to make it shut off early. The more you turn that adjustment counter- clockwise, the longer the cycles will be. See the word "longer" and the arrow? That is what it's talking about.



Normally on steam you want that as far counter-clockwise as possible but you can try other settings. Where it is now is certainly not right and is likely for the typical forced hot air system.



Carefully move the little wire out of the way and move the adjustment counter-clockwise until it stops and observe. I think you will be amazed at the change.





Personally, so far my favorite thermostats are the Honeywell Visionpro 8000 series. But, I also like the one found in the link below a lot especially for the price. If you want to buy it, buy it from pexsupply as a home improvement store will have a cheaper version with a tiny display likely for more money. Make sure you set it to 1 CPH.



http://www.pexsupply.com/Honeywell-TH5110D1022-The-FocusPRO-Large-Screen-Non-Programmable-Digital-Thermostat-Premier-White-4088000-p





Your erratic voltage readings, did you have the meter set to AC? The supply is likely 24V AC +- a few volts.

[Deleted User]

Thanks very much!

That makes sense. Right now it is around 0.6, and it looks like it only goes to 0.8, so I should turn it to 0.8 (counter clockwise)?



Thanks also for the links. So those thermostats will work with a very low-voltage system?



Man, I'm low voltage, low pressure, now if I could just get it lower fuel use.



Edit - Doh! Yes I did have it on DC Volts, and I get a steady 25-26 Volts on the AC setting. I sure appreciate the help.

ChrisJ

Anticipator

I would turn it as far counter clockwise as it will go, not sure if that is 0.8 or not?. Once you see how it behaves start creeping back towards where it is now but very very little at a time, like not even a full line. Just remember those wires are old and fragile! For steam its typically recommended to leave it full counter clockwise but if you get a lot of overshooting you can reduce the cycle length.



The thermostat I pasted a link to will work on a 24V AC system yes.

[Deleted User]

What a difference!

The burner is on for a lot longer now, and I'm getting heat in places I'm not used to seeing it. But I still have 0 pressure. The airflow from rad vents is barely detectable, and none of the radiators heat to the vent end. I can only imagine what it would be like if I had a few ounces of pressure.



Big progress though - now I know it is the thermostat turning it off, not pressure or anything else.



Two questions now:



I'm guessing this is a symptom of an undersized boiler? (actually probably the right size but no longer working well 95 years later). It can't produce steam faster than it condenses, so it just has to go and go. Does that sound right, or maybe I need more insulation? The mains are probably 85% insulated, none of the fittings).



Second question is about the VisionPro 5110D thermostat compared to this one. It seems this one is continually adjustable. But the VisionPro would just be set at 1 cycle per hour. As far as tweaking the anticipator setting, should I be just aiming for 1 cycle per hour, or what?



Thanks again for the very useful help.

EBEBRATT-Ed

pressure

You have been wasting fuel because someone at some time changed the thermostat without adjusting the anticipator setting. Now that you have that somewhat under control and the boiler is running a longer cycle your getting better heat.

Don't worry about the steam pressure if the house is heating reasonably well and the radiators furthest from the boiler are getting heat your probably ok. Make sure all the vents are working.

next, Insulation, windows etc, new heat loss, new boiler

Jamie Hall

Many systems

don't show any significant pressure until all the radiation is fully satisfied -- the only pressure being what is needed to push the steam to the farthest radiators, and the way these things were piped, that's an ounce or two.  Max.



And yes, it sounds to me as though what you are seeing is a symptom of a boiler very closely matched to its load when it was new, and possibly not performing as well as it might now.



Which immediately brings to mind: what can you do to help that boiler out?  And the answer is -- have someone come (unless you are a really good burner tech yourself) and thoroughly clean the boiler fireside.  Then make sure that the burner assembly is in top notch condition, and that it is really getting the correct gas pressure, and that the air controls are set properly.  Also that the draught is set correctly.



In other words, give that old baby a thorough cleaning and tuneup.



You might be surprised what a difference that could make!



On the thermostat -- no need to change it.  You've got the anticipator set much better now.  You can fiddle with it a little, but so long as it allows the boiler to run long enough to satisfy the radiation, but not so long as to overshoot the desired temperature too far, you should be just fine -- and it sounds as though you are pretty close right now.  The only real advantage to a new thermostat would be to program setbacks -- and setbacks are problematic.

[Deleted User]

Wow

I can't express how much you guys have helped me in this forum. Thank you so much.



That cleaning and burner tuneup sounds like a great idea. I hope I can find a real pro to do that in my little isolated town.



No, I don't need setbacks. My wife would definitely not favor that idea. I'll just stick with the old mercury switch honeywell (T822D1008 - I even found a manual online at www.manualslib.com).

Hap_Hazzard

Clock your gas meter

You can get a good idea of whether the burners are turning gas into heat at the appropriate rate by clocking your gas meter.



Turn off your water heater and other gas-fired appliances, then turn up the thermostat so it's calling for heat for long enough to get a reading, then put on your coat, grab a stopwatch and go out to the meter.



Time how long it takes the 2 ft³ dial to make a complete revolution. Divide 3600 by that number to get ft³/hr. Multiply by 1,020 to get BTU/hr. Compare this to your input rating. If it's consistent with your impression that the boiler is under-firing, mention this to the combustion tech and ask him if he can adjust it. Don't try to adjust it yourself, unless you have the tools and training, including a combustion analyzer.

[Deleted User]

Gas meter

Interesting. OK, I got 36.8 seconds to use 2 cubic feet (assuming that's what a full turn of that dial means). Dividing 3600 by that and multiplying by 1020 gives 99,783. Is the point of the 3600 to convert seconds to hours? In that case we would divide the seconds by 3600, x 1020 gives 10.43.



Either way, I don't have an input rating to compare it to, unless there is a table somewhere of input ratings for a circa 1918 American Radiator Co. Redflash No. 1.



Also, that doesn't account for the heat that is wasted heating up the boiler room or going up the chimney, does it? That's probably a lot more than modern boilers.

Jamie Hall

Comparison to input ratings

can be useful -- if you can find them.  Somehow, I doubt that either your boiler's ratings or the burner's ratings are all the easily available... !



What is more important, in my view -- particularly with older boilers -- is to make sure that the thing is firing as efficiently as it can be made to do.  (sort of goes back to my comment on finding a good burner tech.  I agree that Gunnison is a little out of the way, but there must be one somewhere... !).  There are two aspects to this: first, is the fuel to air ratio optimal?  The only way to find that out is to use a combustion test meter; there really is no substitute.  The other aspect is how well the flame can transfer heat to the boiler metal and then to the water in the boiler -- which is why I recommended that the fireside be thoroughly cleaned up.  It's amazing what a little soot will do to the heat transfer.



The end result will be that you will be getting all the heat you can out of the gas -- the most efficient mixture possible -- and as much of that heat as is possible will be transferred to the boiler, rather than going out the stack (and that heat truly is wasted -- although you don't want it to be too cool, unless the boiler is designed to condense and you have the correct flues for that to happen without damage -- which your 1918 unit surely is not!).  Stray heat going into the basement may or may not really count as waste, however.  One can also look at it as keeping the basement just a bit warmer than it might otherwise be, and if it isn't too draughty, this may not be a bad thing.

Pughie1

Redflash #1

As long as you are at this have you measureed your standing radiation yet? In other words your radiators to determin what your Sq Ft load is. This would be a good thing to know.

I have an old boiler rating handbook showing the Redflash #1. I am not smart enough to post it here but, I'll give you the rating for the #1-6

              Net steam rating ----- 305  (I assume Sq. Ft)

              Fire box size------151/2" wide  x  191/2" long

There are 7 different sizes of the Redflash #1   1-4 - 1-10 

                    John Pughe

                                                    .

[Deleted User]

Size 8?

Thanks. Sizing up the radiation is on my agenda. I haven't found a detailed guide for how to do that yet, including risers, and I still can't be sure of the difference between column and tube-type radiators, even after looking at drawings and photos, so I'm sure I'll be posting photos and asking for help when the time comes.



There's a plate on the bottom door that says "Number: I S 8" and "Series: 8".

Don't know if that Number has a one, a capital i, or lower-case L. But I guess this would be size 8?

Pughie1

Size 8

Sorry I can't scan this page for you to illustrate all the ratings. However, if it is a Redflash #1 - 8 the

                 Net steam rating is 400

                 Firebox Size  151/2" x 271/2" long

As far as measuring your radiators go the guys here can help you with this. From there you can work all the way back to your input you already measured by clocking your gas meter.

[Deleted User]

Great info

That's great info, thanks. I'll record all this and try to figure it out later after measuring the radiation.



I do have a question about the BTU/hr calculation though, just to be sure I did it right. If I recorded the time for one full turn of the 2 cu. ft. dial on the meter, is that 2 cu. ft.? So if I divide 3600 by the 36.8 seconds, that gives 97.8, but don't I still need to multiply by 2 to get cubic feet per hour?

Pughie1

formula

If my memory serves me correctly the formula is:

    #of seconds/Hr x BTU content of fuel x Test dial size divided by the # of seconds for one revolution of the dial



                         3600 X 1020 X 2  divided by # of second of the 2ft dial



1020 represents the number of BTU's/cu ft of the gas. You could get your gas companies value they use by contacting them.

[Deleted User]

That makes sense to me

Thanks!

Mike Kusiak_2

Error in original calculation

Yes, there is a factor of two error in your earlier gas calculation.



If you consume 2 cu ft in 36.8 seconds, then you use 1 cu ft in 18.4 sec. Then dividing 3600 by 18.4 gives you cu ft / hour or 195.7 cubic feet per hour.



At 1020 BTU/cu ft, you have 195.7 x 1020, or a firing rate of 199,600 BTU per hour

Pughie1

Formula

Good catch Mike!   John

Hap_Hazzard

Calculations

The 3600 is to convert 1 ft³ / n seconds to ft³/hr. I forgot to tell you to divide the number of seconds by 2 first because the dial measures 2 ft³ per revolution.



2 ft³/36.8 sec.

1 ft³/18.4 sec.

196.65 ft³/hr.

199,565 btu/hr.



Comparing this to the gross input does account for losses. That's why you use gross input instead of gross output or net output. Gross input includes everything.



If we can't find a rating for your boiler (and I wouldn't give up without a stroll through this sites incredible online library) we can arrive at a rough estimate by starting with your connected load and working backwards. It would definitely be better to have a rating though.