Why no steam pressure in boiler?

mel rowe

Thanks Barbarossa. I won't be able to get the gas usage data for a few days. I will post it then. In the interim, where can I find info on expected gas consumption for various size boilers?

mel rowe

Why no steam pressure in boiler?

I was trying to help a friend with heat problems, using some of my newfound knowledge from TLASH and this site. I was stumped in 45 min. Turned on the system. Took 36 min. for the steam to get around the main to the vent. I know the vent is slow and needs to be replaced with a Gorton NO. 2. However, no pressure ever showed on the gage (0-5psi). When I popped the blowoff valve--No steam. Just to make sure the line to the gauge was clear I took off the gauge and probed. It was clear.How could there be no steam pressure whatsoever after running for so long? By the way, this is a Weil McLain EG-40 boiler, rated at 125000 btu.

Bob W._3

Could be running up the stack. Did you check for a leaking boiler?

mel rowe

Thanks Bob. No sign of a leak that I can determine. This boiler uses hardly any water at all. A thought came to mind. Since this is my friend's boiler, I don't know how well it has been kept cleaned out. Could it have possibly collected so much sludge from the old piping and rads that the boiler is unable to get hot enough to steam? Another curious thing is that the water line is so steady, it never even wiggles when operating, yet it did drop slightly over the 40 min. I was watching it.

thfurnitureguy_4

Did the radiators heat? if so it is steaming. It is just taking a long time to reach the main vent. It will shut off as soon as the stat is happy, so it may still be venting air and not building pressure. Also if insulation is missing on your mains it will most likly not build pressure during a normal cycle. Bare pipe is like a huge radiator. It will make the system act undersized.

gerry gill

does the system work?

do the radiators get hot?

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mel rowe

Out of the 9 rads, I think only 4 were showing signs of heat and only partially across the rad. In fact my friend had removed the vents from 2 rads and that is the only way they ever even get warm.

Barbarossa

Can you confirm the fireing rate by clocking the meter.

mel rowe

I'm not quite sure what you want me to check. I can easily check the gas usage on the meter. Is there anything else you would want? By the way, is it possible that sludge has accumulated so badly in the boiler that it just won't make steam?

Barbarossa

If the input of the boiler is say 145,000 BTUS then on natural gas it would be firing at about 145 Cu/Ft hour. see how much the the gasmeter turns for the time it fires and see if it is firing at the correct rate. It can also have sluge on the water side and pluging on the fire side which would make for high stack temps and low eff.With gas costs rising you might be better served to find a profesional to check the above, payback would be quick and you do not have combustion equip. to do it right.

Barbarossa

Usual rule of thumb for natural gas is input btus on boiler tag divided by the 1000 btu/cu/ft for standard natural gas. Thus if the input rating is 168,000 btus it should fire at about 168 cu/ft each running hour. This value changes for other fuels such as LP or propane which can vary between 2500 and 3000 btus a ft.