Under 2 ounces/in2?

Brian_74

Last night I hooked up a new 35 oz/in2 gauge. The first time the boiler fired up, the needle showed mostly a vacuum. Once the system had finished running and had cooled off, I adjusted the 0 on the gauge. The next time I was able to see it in action it worked better, but still never went above 2 oz/in2. Is this possible?



I have an Ideal Heating Equipment Company vapor system from 1929. The W-R Pressure Control is set at 3/4 Lb. I don't believe that the pressure control ever stops the boiler; I think it's all the thermostat.



I don't know if it's relevant, but the boiler typically runs 17-20 minutes (thermostat click on to click off). Depending on how cold it is outside, it will run once every 2 to 8 hours (as best as I can determine. I don't know what it does from midnight to 6am).



I'm wondering whether the gauge is bad, or whether there's something else wrong, or whether everything is ok. Any thoughts?

David Nadle

Check the pigtail

The pigtail may be clogged.

Gordo

Low Pressure

Just about all 2-pipe systems we come in contact with get tested with a 0-30 in H2O gauge (17 oz/in2).  On most of these systems, the gauge will not move beyond 3 in H2O (a bit less than 2oz/in2) for a long time.  Meanwhile, the radiators are all getting hot. 



Your boiler may be under-fired or under sized, if you go by the Book.  Some (Biolerpro) would say your boiler may be right-sized.  I think he may be correct.



Even one-pipe systems show this effect.  The radiators all start getting hot at ridiculously low pressures (2-3 in H2O), and, unless the boiler is grossly over-sized, only slowly start to show pressure on the gauge.



It's just amazing!

Unknown

Vapor System

Hi Brian - Did you get all your traps fixed?  If so what you should do is shut all the radiators off and if the boiler is making steam it should build pressure and trip the cut off.  Are all your radiators getting hot?

- Rod

Brian_74

Thanks for the suggestions

I appreciate the help, guys.



I know that the pigtail isn't clogged. I checked it out only a few weeks ago (and it wasn't clogged).



According to my calculations, I need a boiler with an output of 81,600 BtuH. The one I have is rated 168,000 BtuH. The radiators all get hot. At least until I get this month's gas bill, I'm happy with the system. Although, as Rod remembered, I still need to replace the traps.



If I shut off all the radiators and make some steam, what would that tell us, Rod? Is that just to determine if the gauge is good?

Unknown

Try it

Hi Brian- Yes it should. However keep an eye on things and be ready to shut it down so it doesn't go over 3 PSI. I'm wondering if you are actually making steam volume or just simmering.  

- Rod

Gordo

Boiler May Be Grossly Underfired

Or have a hole at the waterline. 

Brian_74

Don't think it's underfired

I had a heating pro inspect the boiler at the start of the season. He checked the gas pressure and increased the flow. This makes me think it's not underfired, but I'd be the first to admit I'm not certain I know exactly what underfired is.



If there were a hole, wouldn't I see water leaking or maybe steam?

Brian_74

Any risk to shut off valves?

Rod, aside from shutting off the heating in two unused rooms, I haven't messed with the shut off valves. I'm I risking making a mess of things if I try using them now?



I think I'm making steam. The water level in the gauge glass goes down and then slowly rises once the cycle is over. And then there's the hammer about a third of the way into the cycle (usually ~7 minutes into a 20 minute cycle). Would that happen if the boiler were only simmering?

Gordo

A Hole at the Water Line

Would not always leak water into the fireside of the boiler.  It would just leak steam  when the boiler was running.  How often do you have to fill it?



You could "clock" the gas meter while the boiler (and only the boiler) is running. 

How long does it take for the 2 cu ft dial to go one revolution?

Brian_74

Not often

I don't have to add water very often. I have been doing extra blow downs lately just to see if I could keep the water a bit cleaner. Even then, I think I've add some water once a month at most.



I'll try the clocking idea, and report back.

Brian_74

32.5 seconds

I timed it 3 times. The average time for the gas meter to make one full revolution with only the boiler firing is 32.5 seconds. What does that mean?

jpf321

for what it's worth ...

realizing that my system is probably quite different from yours (and mine likely very inefficient and overfired (as steamhead pointed out to me))...but I only get above 1oz-2oz after about 31-33min (from a warm boiler (my aquastat is at 170F)) .. but I get to 5oz-6oz by 41mins



if you are consistently satisfying your t-stat to your desired comfort level without exceeding 2oz, you're doing well I think. I seem to be right on the cusp of that feat...sometimes I will trip on pressure (5oz-6oz) just seconds before my t-stat clicks off.



in fact, i can almost tell you how long my boiler's been buring this cycle by counting the hot sections of my 24section rad...because I know that very soon after that last section gets hot (in my otherwised balanced system) .. i will trip on pressure and my t-stat will click off

Gordo

Was That...

...the 1/2 cu ft dial or the 2 cu ft dial?

JH_2

my guage rarely moves off zero

Another anecdotal story - I think you have no need to worry.



I put a new 0-3psi guage on my single pipe system this year.  Im slightly oversized (250ish sq ft on a boiler rated for 358).  Brand new guage, brand new clean brass pigtail.  I am well vented (1- #2 and 3- #1 gortons on the mains) and fully insulated on the dist. pipes.



Most of the time that gauge never moves off of zero before all the rads are hot and the T-stat satisfies.  The only time I see pressure is on a long cycle to recover from setback on a cold day. Then it runs for at least 45 min before the needle even moves, and takes another 10 or so to reach the 1.5psi cut out.

David Nadle

That's a nice ball valve

That ball valve looks like an antique or something. But if it ever got closed and not noticed...

 

Brian_74

The 2 cu ft. dial

Is that a new land speed record? (I hope not)

Brian_74

Thanks for the anecdotes

Thanks, guy. I appreciate knowing that this is normal.

Brian_74

Tried a different experiment

Hi Rod,



Well, I discovered that at least one of my valves won't shut. That's a story for another thread. I did try a slight variation on the experiment. I added water until the sight glass was at 3/4. That increased the pressure to 5+ oz/in2. I'm not sure that answers the simmering vs. steaming question. In fact, given that the system is open, I'm not sure I understand why increasing the water level led to a rise in pressure, but there it is.



Brian

Mike Kusiak_2

Pretty high

If you are using 2 CuFt in 32.5 sec, that comes out to 3.69 CuFt/ min or 221.5 CuFt/hour. Assuming 1 Therm = 100K BTU = 100 CuFt, your gas heat input or firing rate is about 220K BTU per hour, which seems high.



You mention that the technician raised the firing. I wonder what it was before?

Brian_74

He didn't say

The technician didn't give me any numbers. He just said it was a bit low and then raised it.

Gordo

By Raising the Water Level

You may have increased the surface area of the water/boiler interface and thereby increased your steam output per unit of heat consumed.

Unknown

Not Much Pressure

Hi Brian-   Since all the radiators are getting hot I wouldn't do much in the way of modifications at this time. Just wait till spring until after the boiler has shut down for the season. That way you aren't in a rush to fix things before your family freezes. You need to re route the returns and fix the traps. It sounds as though you'll need to rebuild some of the radiator valves as well. I "exercise" mine regularly every couple of weeks as that keeps them moving easily. I'm not quite sure why I do this as on a one pipe steam like mine the radiator inlet valves are next to useless. However on a  2 pipe steam like yours you can throttle down the steam entering the radiator without causing a problem and this gives you some control over the heating in the rooms. Re routing the returns and rebuilding the traps will increase the efficiency as this will keep the steam in the radiators where it does the most good.

As you mentioned your boiler is way oversized. I imagine that this had to have been addressed somewhere in the past and burner heat was turned down so that your boiler  now possibly slightly underfired.  You are making some steam otherwise your radiators wouldn't be getting warm. It's just that you don't have much reserve however when you fix the traps this should give you more. Building pressure is just a waste of fuel so you seem to be at the perfect balance point.

Adding more water to the boiler and raising the waterline will probably get you in the same situation as before, producing wet steam, so I'd approach raising the waterline carefully.

I might mention that Gordo is a very experienced steam pro so take his recommendations seriously. I do and I also appreciate the contribution that he and the other steam pros make to the Wall and in helping out homeowners like myself.

- Rod

Brian_74

Thanks, everyone!

Hi Rod--Thanks for pulling together all the parts of this thread. It really helps. I wasn't sure about rerouting the returns. Why do I need to do that? Or did I misunderstand you?



I am very grateful for all the help I've received from everyone here. As far as I know, there are no steam pros around here, and so I'm becoming my own and I know I couldn't do it without all of you. Thanks!

Unknown

Returns

Hi Brian-  As I remember it, didn't your returns (the one from the steam main and the one from the return main) connect together above the boiler's waterline? (Below the waterline in the Wet Return is okay as the water seals off the ends of the pipes so steam can't travel to the other pipe)  If they do, this is a "No-No" as the steam from the steam main will "short circuit" directly to the return main and neutralize  the pressure differential between the two mains. You want the steam to have to route through the radiators.

I could be thinking of another person's system as my computer crashed about a week back and I lost a lot of thread pictures so I'm going by memory.

- Rod

Brian_74

check valves

Hi Rod, I think that's someone else. My returns connect maybe 6'' off the floor. I think that the issue with mine is that there are two check valves in the wet returns that I don't need. There's one running horizontally between the two returns you're talking about. It's what connects them. And then there's another one closer to the boiler after the two returning are merged into one larger pipe.



Thanks for reminding me about this! I should keep a list. And check it twice.



Brian

Unknown

Got it Straight!

Hi Brian-  LOL! Okay.. I now have the right mental image of the returns connected with the right boiler!

Sorry for the confusion. On these ongoing threads you pickup multiple mental images from the written description and pictures provided and I guess I was experiencing brain overload! - Rod

nicholas bonham-carter

I "exercise" mine regularly every couple of weeks

one way to limber up those valves before you exercise them might be to loosen the packing nut a little bit, before turning the valve stem.--nbc

Brian_74

I think I have vapor valves

Thanks, nbc. Most of the valve handles in my house are the standard issue black bakelite, and I think that will work. The ones I'm most worried about are pictured below. On this particular one, the handle just spins. On another one, the square shaft that comes out from the center easily drops down. I was able to pull it back out by carefully threading the handle screw back into it. All of them probably need the rubber gasket replaced. These don't look as cool as the one shown on the Ideal Heating Equipment Company of Cleveland info posted elsewhere here (where I got my avatar). I'd like to keep them. Anyone know how to rebuild them?

Gordo

Oh, Yes

Those are classic vapor system valves!



Re-building those valves can be a challenge. 



Do you have radiators that heat up very quickly,  while others  on your system seem to heat up slower?

Gordo

Thank You

For the kind words, Mr. Rod.

Brian_74

I never fall for the easy stuff

Thanks, Gordo. I think that the best thing to do would be to find some extra valves to rebuild first, and then replace what I have. Any advice about finding valves and parts--or is that part of the challenge?