New steam boiler oversized?

Dan_54

Here are a couple pictures of the boiler and piping.

Dan_54

New steam boiler oversized?

Hello,

Looking for some second and third opinions on a recent residential gas-fired steam boiler installation. I live in an 1100 sq. foot condo with a 1 pipe steam radiator system. My plumber recently replaced the old oil-fired boiler with a new gas-fired model (Burnham PIN5, 140 MBH input, EDR=358 sq ft).

From the beginning, there was water-hammer in the pipes, much louder than with the old boiler. I drained and replaced all the water in the system several times, and then skimmed the boiler several times. Shimmed all the radiators, checked all the valves. Still noisy. Finally, after doing some reading on this forum, I turned the pressuretrol setting down to 2 PSI from its initial setting of 5 PSI.

This made the pipes much quieter (though not as quiet as with the old boiler), and reduced the monthly gas bill by $75. I'd love to turn the pressuretrol down further, but with the main pressuretrol setting at 2 PSI instead of 5, the burn cycles are already much shorter. 2-4 minutes on, then 6 minutes off, then 2-4 minutes on...

Suspecting that the boiler was potentially oversized, I calculated the EDR of my radiators using the worksheet on the Burnham website, and got 189 sq. feet. Every foot of steam pipe in the basement is well insulated. I asked my plumber why he didn't install a boiler the next size down (PIN4; 105 MBH input, EDR=271 sq. ft), and he told me the PIN4 is only good for about 5 radiators, and we have 7. He said the 2-4 minute cycle times shouldn't really affect burn efficiency or boiler longevity, and if the radiators are getting hot, we're good.

Are 2-4 minute burn cycles really not detrimental over the long-term? Does Burnham really overstate the capacity of their steam boilers? If the boiler is oversized, what are my options? The burner already appears to be down-fired, as it's only taking in 130 MBH instead of the rated 140 MBH. My pressuretrol differential setting (subtractive in this case) is set to 2 PSI, same as the cut-out setting.

Thanks for any thoughts on this.

-Dan

Dan_29

boiler oversized?

Go to the top of this page. Click on "Systems". Then click on "steam". Click on water hammer. It lists several causes and solutions in more complete manner than I can type here. I would be suspect of an installer who cranks your system up to 5psi gauge. The Empire State Building runs on that pressure.

Dan R.

EBEBRATT-Ed

Water hammer could mean wet steam. Check (or have checked) all air vents and pitch on piping. The boiler could be oversized. Longer run time would be better.

ED

Brad White_185

Empire State Building

actually runs on 2 PSI, reserving 3 PSI on the very coldest days according to their facilities engineer. Just to reinforce the point that a house does not need nearly so much!

Concerned Apartment Owner

Empire State Building Steam Pressure

When the steam pressure is measured, where exactly is it measured. I've read that low pressure steam systems run at between 1.5 lbs and 2.0 lbs. In the case of the Empire State Building running at 2.0 lbs, would the pressure in a radiator on the 50th floor and the pressure in a radiator on the 10th floor be 2.0 lbs. What is if you're using a vacuum system. Thanks folks...

Concerned Apartment Owner

For Brad White

When the steam pressure is measured, where exactly is it measured. I've read that low pressure steam systems run at between 1.5 lbs and 2.0 lbs. In the case of the Empire State Building running at 2.0 lbs, would the pressure in a radiator on the 50th floor and the pressure in a radiator on the 10th floor be 2.0 lbs. What is if you're using a vacuum system. Thanks folks...

Unknown

some pictures

All of the above adivices are helpful, however, some pictures of your heating unit will help us wall addicts to serve you better..

Long Beach Ed

YES

Assuming that your measurements are correct, the boiler is grossly over sized for the application. If it is piped correctly and the radiators and mains properly vented, it is short cycling because it is TOO BIG. A 2-4 minute cycle will probably double your fuel costs.

This is an improper and irresponsible installation by someone who didn't do his calculations.

Lets see some pictures of the piping above the boiler. I'm sure that will just support our opinion further.

Dan_54

boiler & piping pics

Dear Wall addicts,

Here are a couple pictures of the boiler and piping. The horizontal white pipes in the background are PVC drain pipes; the steam pipes are also white because they're insulated. Let me know if anything is unclear and I'll post some more photos.

The radiator vents seem to be working properly. There is no main vent in the system. This is the first steam-heated place I've lived in, so it's hard for me to say whether the radiator vents are hissing too much for lack of a main vent. I asked my plumber about the lack of a main vent, and he said they weren't always necessary.

Thanks very much for your responses.

-Dan N.

bob young

pvc

you better put some proper hangers on the pvc pipe or it will soon look like spagetti

Steamhead (in transit)

No main vent?

Your plumber is wrong. This is probably contributing to the short-cycling. Measure the length and diameter of your steam main (looks like there's only one, if not, measure them all) and we can tell you what you need.

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HitzKup_2

Near Boiler Piping

Dan:
Your near boiler piping lacks a swing joint and the 2 mains are supposed to come out individually from the header.

Unknown

look like the supply

Looks like the header pipings is undersized... What's the boiler model number and spec will tell the correct sizing. And as others said, take offs should coming off the header piping. Get a real boiler pro to do the job corectly. And yes. Install more hangers on the pvc pipings as codes required one every 5 ft..

Dan_54

piping specs

Some clarification: there's only 1 main. The top pipe that goes off to the left only feeds 1 radiator.

The boiler is a Burnham IN5. The manual states it should have 2" riser and header pipes, and that's indeed what it has. The main is 18 ft of 2" pipe. Is that enough to tell what size main vent would be required?

Though there's no swing joint, I'm inclined to think the near-boiler piping is in good shape. It didn't change much after the new boiler was installed, and the old oil-fired boiler had no problem with it. Similarly with the lack of a main vent--the old boiler didn't short cycle or make a racket in the pipes. The only part of the system that's changed is the boiler, which seems too large for the application.

Thanks again for the help,
Dan N.

joe lambert_2

new boiler

Yeah that boiler is over sized but the water hammer might have something to do with the fact that new boilers and the new piping has oil in it, which causes water surging and water inside it. A new boiler needs to be cleaned and skimmed for it to operate correctly. This procedure is listed in your owner’s manual. That Hartford loop should also be 2" below the water line and the water line should be in the center of the gauge glass. You should also have a minimum of 24" from where the riser coming out of the boiler starts to the bottom of the header.

To test the water condition inside the boiler try this. Close off both the valves to the gauge glass. Open the drain caulk at the bottom of the gauge glass while the boiler is steaming. Open only the top valve with the drain caulk open and the boiler steaming. If you see water pouring over the top and down the gauge glass than the boiler water is fluctuating violently and needs to be cleaned. If the boiler water is good than only steam should come out.

mike jones

boiler water quality

the steam came out the bottom, out of the drain calk, we sort of expected it to come out of the top, since the top valuve was open and only the drain open at the bottom. nothing came out the top, no water, no steam. is this bass ackwards, or good water quality?