Joined on September 16, 2002
Last Post on September 15, 2014
@ September 15, 2014 3:51 PM in One-pipe counterflow projectThe biggest difference for the counterflow system -- once you get out into the system -- is that the pipes have to be big enough and have enough slope. If the system doesn't bang, that's probably OK just as it is. If it does, the solutions are the usual suspects -- sags in the pipes, that sort of thing.
Near boiler piping is a little more critical, but if you are generous and pipe the boiler properly (a drop header goes a long way here!) that shouldn't be a problem, either.
And no, you don't need higher pressure. 1 1/2 pounds should be ample.
Venting venting venting -- I'll bet you a coffee that you'll find that you could use more main venting...
@ September 15, 2014 11:03 AM in Ideal (Subtractive) Pressuretrol Settings?can't do much better than what you have with a pressuretrol. The cutout pressure -- that 1.8 psi -- is a bit higher than I would like to see (1.5 psi would be better) but pressuretrols can get a little flaky down in that pressure range, so that is probably as good as it's going to get. Myself I might set the differential a little smaller -- 1 psi rather than 1.3 -- again simply because pressuretrols are a little flaky at very low pressures.
The way these things work is that the main setting determines the pressure at which the pressuretrol turns off the power to the burner. When the pressure rises, eventually the sensing switch will turn off. Then, as the pressure falls, eventually the pressure will drop to the point where the switch turns back on. The differential setting determines the difference between that off pressure and the on pressure. It is called subtractive, because the difference is applied between the off pressure and the on pressure -- so the on pressure is found by subtracting the differential from the main off pressure.
@ September 9, 2014 4:33 PM in Steam boiler loses water when off.no, probably not -- so long as your low water cutoff is working properly. If, for some reason, it wasn't and you had only one (a lot or residential boilers do have only one) then there is the possibility that you could unknowingly dry fire the boiler -- and that is very dangerous.
So is adding water to a really hot boiler (not normal small additions, but coming down, finding the boiler off, and adding a lot of cold is not recommended...).
On the other hand, I've yet to know of a leak which got better with time, so it would be well to find the leak and fix it. Which may mean, sadly, a new boiler.
@ September 8, 2014 8:49 PM in two remote radiators not workinglike a venting problem. If the air can't get out, the steam can't get in. Check those vents.
@ September 8, 2014 8:48 PM in hotelmanit's not impossible to fix -- in fact, it may not be that hard. If... there are tension rods on the radiator, or if you can figure out what's holding it together, it may be possible to pry (very carefully!) the banks apart and see what is creating the leak. It may be, depending on how the thing is put together, that there is a machined nipple which joins the sections. They can be replaced. If all else fails, you may be able to form a gasket using the red RTV used on auto engines. Then put the whole thing back together.
Let us know a little more about this thing...
@ September 2, 2014 10:31 PM in Going around obsticalsold houses. There is always something new and different to play with... That soil pipe is nothing if not ingenious.
Honestly, if the radiator is heating and isn't hammering, I think I'd leave it alone. But -- I tend to operate on the principle of "if it ain't broke, don't fix it" which drives some of the folks I work with who like to have things just so slightly nuts.
You asked a couple of posts ago about copper. On a wet return -- which is what your drip leg would amount to, assuming you snaked it on around back to the boiler -- you can quite safely use copper below the water line of the boiler. No problem at all. Above the water line is not so good. The problem is the expansion of the copper when it gets hot, of course. Not that it absolutely cannot be used; it can, but one must make sure that somehow the copper is allowed to expand without putting stress on the soldered joints, especially stress tending to twist them. (Before someone has a heart attack, copper in a boiler header is an absolute no no, particularly if there are two or more risers -- it will tear the boiler apart). This may require considerable ingenuity. So it is better to use threaded black iron above the water line. It's easier...
@ August 31, 2014 9:27 PM in ownerbut if that's a residential boiler there is something really wrong with the controls. If it were mine I wouldn't operate it until I found out a lot more about it and fixed the problems.
@ August 31, 2014 5:41 PM in Cut In on New Steam Boiler??I think a number of us have, but I'll reply... the place I take care of is largish (about 7,000 square feet usable, on three floors). The boiler is in the middle of the basement. The longest run to any radiator is around 80 feet. The system is controlled by a vapourstat, with a cutin currently of around 3 ounces and a cutout around 9 ounces -- which it never reaches, except on recovering from a setback situation (and I don't use setbacks).
It takes around 9 minutes for heat to reach the farthest radiators from the time the thermostat calls for heat -- that includes the time it takes the boiler to raise steam, which is about 5 minutes. The pressure at that point at the boiler is on the order of 2 ounces, more or less. It will rise -- but only very very slowly (the boiler is an excellent match to the system) to perhaps as much as 5 ounces by the time all the radiators are hot across.
So, bottom line is no. No problem with getting steam to the farthest radiators on close to no pressure at all.
Now. If your venting isn't adequate, all bets are off. You can raise enough pressure to move a locomotive and, without adequate venting, you will still not get steam to the poorly vented radiators.
@ August 31, 2014 2:28 PM in Cut In on New Steam Boiler??such as yours should not operate at more than 1 1/2 to 2 psi -- which is a real stretch for a pressuretrol.
However, with a great deal of care, it can be done. There are two types of pressuretrols: subtrractive and additive. In the subtractive variety, you set the cutout pressure on the main scale and the cutin pressure is set by the differential, which is subtracted from the main scale cutout pressure. If that is the flavour you have (it will say on the control) set the main cutout pressure to 1 1/2 psi, and the differential to 1 psi. If you can... You will need to fire up the boiler and wait for the pressure to rise (which, if you don't have king valves to shut off the system from the boiler, may take a while -- it should!) and check to make sure that the boiler does cut off and cut back in. Set that low pressuretrols can be just a bit flaky.
If the pressuretrol is additive, the principle is exactly the same, except that you set the cutin pressure on the main scale and the cutout is determined by that plus the differential. In that case, set the cutin at 1/2 psi or as low as it will go, and the differential at 1 psi. Test it as above.
A better approach is to buy a vapourstat for the main control, setting it at 12 to 16 OUNCES per square inch cutout, and keeping the pressuretrol as a safety backup.
As NBC noted, getting a low pressure gauge in on the act isn't a bad idea -- then you can see what's really happening.
@ August 29, 2014 7:22 PM in Going around obsticalsI think I have to disagree with Icesailor. Much as I hate to, since he's forgotten more about this stuff than I've ever known.
But I don't think it will pound, and I do think it will work. The key to it is that the pressure differential between the two sides of the arrangement is essentially nil, and thus there will be very little reason for condensate to be pushed out of the lower loop to where it would hammer. To make doubly sure of this, though, I would make it so that the arrangement is not quite symmetrical. Specifically, I would make the lead on the radiator side come off about half an inch higher than the line coming in from the other side. This should help ensure that condensate will not be able to move out of the low loop into the radiator side.
@ August 27, 2014 9:02 PM in BTU needed on Oil to Gas convesionthat the BTU output from the burner must be within the recommended range for the boiler... you don't give the model number, so we can't help with that.
@ August 26, 2014 7:57 PM in Steam versus Hot Airis wonderful. I've never been really able to say that this piece or that is my favourite favourite, though. Seems to vary with the phase of the moon, or something. But there is that. The Widor Fifth symphony is wonderful, too -- if you have the instrument to play it. the Alain Litainies. Perhaps, though the great Ste. Anne triple fugue in E flat major, Bach, if I had to pick just one...
You'll just have to come and visit, that's all! I still have access to a nice little late 1800s tracker organ...
But it always makes me so sad to see a pipe organ neglected...
@ August 26, 2014 9:11 AM in Steam versus Hot Airbut I'm sure you did the best you could.
As to that organ, speaking as one who (oddly) have been a practising, paid organist for various churches for the past 5 decades or so -- besides other, better paying occupations -- sorry about that. But I think you can kiss it goodbye if it is already in need of work. A winter on hot air heat and it will be pretty close to junque -- and unrepairable for any reasonable price. Professional opinion.
@ August 24, 2014 4:25 PM in Adding longer baseboard steam radiatorsReally isn't enough information here to say yes or no. If there is enough capacity in the boiler to handle the extra radiation, that wouldn't be a problem -- so the first thing to do is to add up all your existing radiation in EDR, and compare it to the rating of the boiler, also in EDR. If that indicates you have the capacity to add some more radiation, at least that won't be a problem.
Then there is the question of pipe size feeding the radiators. You don't say whether this is one pipe steam or two pipe steam, but in either case you will want to be sure that the pipes feeding the radiators are big enough to handle the bigger ones. There are tables for that; it depends on what size the pipes are and the EDR of the baseboards.
But... before you do all that, it would worth finding out if the system really is performing as intended. Do you have adequate venting on your mains? Are these baseboards getting hot as fast as the rest of the system? If they are one pipe, are their vents really correct? Then too, is there some reason why these rooms need more heat than was installed? Leaky windows? Worth looking at those things, too...
@ August 24, 2014 11:21 AM in How much flex in piping?If you can move the pipe enough -- and hold it there while you are threading the interfering pipe in -- and get it tight, then from the plumbing and heating standpoint you shouldn't have a problem; that is, it shouldn't leak. However, it is almost sure to be a source of expansion noise, which can be somewhere between not a problem and a real headache.
Can you make that hold a tad bigger towards the wall? I'd rather see you do that, and figure out a way to cover the hole...
Don't you hate it when things like that happen?!
@ August 21, 2014 12:32 PM in legends of the south poleSupercooled water in clouds is a pilot's worst nightmare. The stuff is liquid -- rain, for all practical purposes -- until your wing and tail hit it. Then it turns into ice, heavy ice, practically instantly and you de-icing gear can't get rid of it. If you're really lucky and have been living right, you fly out of it into warmer air and can recover. If not you have an unplanned encounter with mother Earth, which can ruin your whole day.
@ August 19, 2014 8:15 PM in EDR and margin of errora pretty substantial margin for wiggle room in figuring EDR for a system. As NBC said, the best approach is to look for a boiler which is reasonably closely matched to what you figure your EDR to be. Within 10 percent for your EDR calculations is just fine.
@ August 16, 2014 10:04 PM in Temperature-based cut-in for a Vaporstat?I do hope that your time delay is set long enough so that the system does coast up to a high enough temperature to turn off the thermostat.
If not, and the timer times out and the thermostat is still calling for heat, you are going to take quite a hit on the efficiency because you will need to bring that teakettle back up to a boil...
@ August 16, 2014 10:02 PM in Temperature-based cut-in for a Vaporstat?I watched this thread with some interest... I'll be very interested to know if there is a significant fuel savings given identical building conditions (that is, the same amount of overshoot if any at the end of your setback cycles). Frankly, I have my doubts about whether you will be able to tell, as the signal will, I think, be buried in noise.
I did want to respond to a comment in one of the early posts in the thread on "short cycling".
That's a bad term, and I do dearly wish that we could get rid of it.
There are three completely different things involved here.
First, the "short cycling" to which you refer towards the end of a heating cycle. A far better term would be "pressure modulation". What is happening is that the radiation cannot condense the steam quite as fast (one hopes -- if the boiler is reasonably closely matched!) as the boiler can produce it. Since you don't want the pressure to rise, it is necessary to modulate the rate at which the boiler produces steam to match the rate at which the radiation condenses it. One could use a burner where the firing rate varies with pressure, in exactly the same sort of way that the power of your car's engine is varied with load to maintain a constant speed on the hifhway. There are no burner systems that I know of which do this on oil or gas, although there are multi-stage burners which can come closer. So, lacking that capability, we turn the burner on and off to maintain the pressure within a narrow range. In many systems, the minimum off time is set by the burner post purge and pre purge cycle; the on time will be what is required to bring the pressure back up. Is there a loss of efficiency here? I'm not really sure. The burner is off only a very short time, and thus the system never really comes off a boil, never mind cools below boiling. If there is a loss, it is minor -- perhaps half a percentage point, overall.
The second type of short cycling occurs when system shuts down on pressure before the radiation is filled. This almost always indicates that the main venting is inadequate, although it could also indicate that the steam main size is too small (that would be unlikely in an older system). This does have efficiency implications, as well as comfort implications -- the ends of the system get poor heat.
The third type is, in a way, a combination of the first two, and occurs when the boiler is badly oversized.
The second and third types to affect efficiency and fuel usage, no question.
One might add that an ideal system would modulate the firing rate so that the boiler would never shut off, but would fire only just hard enough to match the heat loss from the structure. This can be done with a vacuum vapour system, if you can pull enough vacuum (the heat output of the radiation being, then, a function of the vacuum level and thus condensing temperature) and, of course, can be done rather easily with an hydronic system by varying the water temperature going to the radiation (or the flow).
Back to square one -- I know of no burners with that wide a modulation rate....
@ August 16, 2014 9:21 PM in Yet another boiler sizing question from a newbie...it really is six of one and half a dozen of the other. Either way, they need to be right. Traps have some real points (one reason why they are so common!) in that they either work or they don't, and if they are working properly then you have no problems with getting the right steam flow into the radiators. Orifices, on the other hand, have no moving parts to fail, so if the pressure is right, they will always work -- once they are properly sized for the radiator.
Take your pick...
Traps, I might add, can last a very very long time if they aren't abused -- all the traps on my system are original (about 85 years old). A couple of them have failed open, which would be a nuisance except that I also have Hoffman valves, and the solution is to set the valve to meter the flow, just like an orifice would. Which works just fine. I could replace the failed traps but, honestly, I'm too lazy and too cheap!
You will want a 0 to 16 ounce vapourstat. Set it initially to cutout at 12 ounces and back in at 6. You can dial it down some if you find it works better that way. A low pressure gauge (it can be on the same pigtail) is a big help to make sure that the 'stat is working the way it should; sometimes they do need a bit of calibration. One other type: a snubber (look at http://www.omega.com/pptst/PS_SNUBBERS.html for examples -- must be steam rated) will help to stabilise the vapourstat and prevent it from turning off prematurely on brief blurps and surges.
Keep the standard pressurestat (wire them in series) as a safety backup.
@ August 14, 2014 3:07 PM in radiator steam traps vertical pattern single unionIn fact, there are a lot of systems which were built with orifices. There are a lot more systems which were built -- as nicholas noted -- using valves for the same purpose (the one in the place I take care of is in that category).
Traps on such a system are somewhat in the belt and braces category -- they serve to control things in two situations: first, someone monkeys with the valve and gets it open too far and, second, somehow the pressure gets too high.
I'm reaching a bit out on a limb here, but it is my feeling that you won't be any worse off if you reduce the pressure first, and I'd be very much inclined to bring it right down to about 12 ounces cutoff with a vapourstat. If your church just doesn't have the cash to do that, try taking the existing pressuretrol as low as you can get it to work reliably, which will probably be around a pound and a half cutoff.
This won't hurt anything at all.
Then start with one zone, and put orifices on the convectors which have failed traps first.
Then do the next zone, and so on.
Then go back and work on the ones you didn't do the first time around.
Believe me, I sympathise with the budget woes of churches...
@ August 14, 2014 2:56 PM in UPS or Surge Protection - Condensing Boilersurge protection and power conditioning are two very different things (a UPS is a form of power conditioning).
Surge protection protects against just one thing: overvoltage spikes on one of the hot wires with relation to the neutral. These spikes can be lethal to equipment; depending on the particular bit of hardware, the shape and size of the spike may or may not be a problem (a big old old electric motor, lots of copper, lots of iron) may not be affected by something which will completely fry a bit of digital electronic equipment. If spikes are the problem, the surge protection may be the answer. I would point out that there are flavours of surge protection.
Power conditioning, on the other hand, takes whatever power is coming in and hopefully manipulates it to produce -- in the best forms -- a smooth sine wave or (in three phase) sine waves with the correct nominal voltage between phases (if three phase) and the neutral. It's not that hard or expensive to do for relatively small loads. It begins to get very expensive indeed for larger loads.
One needs to define exactly what the problem is that you are dealing with before figuring out what equipment is necessary to achieve the desired result.