Steam - is this normal?

Gary Schultz

I sure would like to know if my 2 pipe steam system is operating as it should. the problems? 40 minute cycles are the shortest youll see, no pressure build at all on the in/h20 gauge in that time. Will not move steam through CI baseboard appreciably beyond first few sections. If I cut a radiator on that main,it will move the steam about another foot through the bb. Sacrifice 30 edr to gain 3 on the bb? Heaven forbid cut the thermostat back a degree or two, you'll pay dearly when you want that degree back. 66-70* 1hr 15min nonstop. After an hour you will start to build pressure. When the vaporstat kicks off at 14" (8oz), the burners are shut for about 35-45 seconds when it will kick back in at about 4". The house dates to 1929 and was originally coal fired. The rads are definitely not oversized, but maybe sized for a constantly burning coal fire? All traps have new elements. All mains are insulated. Boiler is gas fired W/M EG series, and is sized correctly for the radiation. The rads do heat up fine, except that bb. I have end of main hoffman 75 vents installed. The steam takes about 6 minutes to go the 45'. At the end of the dry return there is just an open nipple for venting. The house though not insulated for the most part, is not at all drafty.
Attatchments include a pdf file diagraming the system piping and radiation.
I have been told that steam is basically pretty effecient, but that just isnt adding up when the gas bill comes
Any thoughts and comments will be most appreciated. If there is any further information you would find useful. please ask and I will respond

Gary Fereday

Have you

taken a section of the bb out and ran water through it? I have seen cast iron BB that was full of casting sand. I think it rinsed off the inside and plugged the lower part of the BB. just an idea! bigugh

Steamhead

Sounds like

the boiler may not be firing at the proper rate. Have the firing rate checked to see if it matches the nameplate.

Also check for a restricted or badly pitched runout between the steam main and the problem baseboard, also between the dry return and the baseboard.

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Unknown

No pressure

Your boiler is sized marginally.

The connected load is 345 EDR. You need another 30% for the heat loss of the steam piping. That is about anothe 90 edr. That brings the the input to the boiler to 435 EDR.

You need about 104 cubic feet per hour of gas supplied to the boiler on the coldest day.

Run the boiler flat out for 1 hour. Take a reading at the gas meter and check what was burned for the hour. If the meter reads less than 100 cubic feet burn in the hour the burner orifice are to small.

Since the boiler was converted from coal to gas the people that did the conversion may have used the net rating of the boiler to size the burner, they should have used the input rating or converted the net rating to an input number.

Additionally, The heat input to a coal boiler may need to grater than the estimated input to supply 345 EDR.

Some coal boilers had so much and stored so much water that another 25 to 50 cubic feet of gas is needed to heat the boiler to provide you with the proper net BTUH to heat the house quicker.

The boiler in your hous should take no more than 10 to 15 minites to get up the head of steam needed to reach all the radiators.

Additionally if the piping is not insulated, insulate the piping before you change or alter thr burner.

Jake.

Gary Schultz

choked bb

If I partially plug dryreturn to restrict airventing, and add a radiator vent to the bb, she will heat from end to end. 3-4" pressure will move the steam nicely through, anything less no dice, moves like a snail, wont make the run by cycles end.

Gary Schultz

firing & piping

After reading a post a few weeks back on converting ccf to btus I did that check, and sure enough, the input was showing 120 instead of the 150,000 specd. Basically turning the EG45 into an EG40. both 4 section boilers. Adjusted the regulator on the gas control, brought it up to spec, and observed carefully. No change, except another foot of bb was heating. I know more steam was blasting through the system, considerably more, but the cycle times did not change, just add 20% to the monthly, thank you very much!
The runout from the main is a bit peculiar. These bb's were added to replace rads some time ago. They ran 3/4 handbent copper piping with screw valve? and 90 into bb. Outlet is also copper and handbent, it is removable and does not have any obstructions. I know 18' is a long run, but with a few inches of pressure she'll heat from tip to toe.
Thank you Steamhead, and love that name! I have been reading the posts on the wall for a while now and am most appreciative of your unflinching love of steam heat, and vapor systems in particular. Your complete confidence in the capabilities and effeciencies of these systems as expressed in earlier posts has done a great deal to keep me hopeful. And of course without Lost Art, I'd be Lost

Boilerpro

I bet teh problem is...

> After reading a post a few weeks back on

> converting ccf to btus I did that check, and sure

> enough, the input was showing 120 instead of the

> 150,000 specd. Basically turning the EG45 into an

> EG40. both 4 section boilers. Adjusted the

> regulator on the gas control, brought it up to

> spec, and observed carefully. No change, except

> another foot of bb was heating. I know more steam

> was blasting through the system, considerably

> more, but the cycle times did not change, just

> add 20% to the monthly, thank you very much! The

> runout from the main is a bit peculiar. These

> bb's were added to replace rads some time ago.

> They ran 3/4 handbent copper piping with screw

> valve? and 90 into bb. Outlet is also copper and

> handbent, it is removable and does not have any

> obstructions. I know 18' is a long run, but with

> a few inches of pressure she'll heat from tip to

> toe. Thank you Steamhead, and love that name! I

> have been reading the posts on the wall for a

> while now and am most appreciative of your

> unflinching love of steam heat, and vapor systems

> in particular. Your complete confidence in the

> capabilities and effeciencies of these systems as

> expressed in earlier posts has done a great deal

> to keep me hopeful. And of course without Lost

> Art, I'd be Lost

Boilerpro

I bet the problem is...

that 3/4 inch runout. I ran into the same problem at my church. They expanded the building and converted the one pipe system to two pipe. One zone combined both original radiation and newer thin tube radiation. The orignal rads retained thier large one pipe sized steam supplies (1-1/4 inch and 1-1/2 inch) and traps were added on the other end of the rads. The new rads were installed with 3/4 inch supplies and steam traps. The new rads were not heating while the old heated very quickly. Throttling the supplies to the original reds to create a little more pressure drop in this supply piping pushed the steam through the new smaller supplies on the newer rads. Also need to think like steam, It goes where ever it is easiest. I'd try reducing that firing rate again and then balance the heat output of the rads with the supply valves. What you may end up with is a system more ressembling an old orifice vapor system than a two pipe steam... getting all the benfits of lower fuel bills, more even heating, and longer boiler life due to less cycling.

Boilerpro

mike jones_2

gas usage

we have 925 sq ft of radis, and the gas meter shows 4 burnt in 1 hour, i assume thats like 400! does this tell us anything of our firing rate for curiousity?



we noted your advice of 100 minimum usage on 400 edr, but is there a maximum expected?