Joined on September 16, 2002
Last Post on August 31, 2014
@ 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.
@ August 13, 2014 7:45 PM in Oil fired flue without barometric damper?with icesailor here (and I have sailed over most of that area, too!).
I don't see how, I really don't, you can have anything like a reasonably constant draught on that boiler without two things, neither of which I see: a barometric damper, to reduce the variations in draught from variations in the wind, and a control damper. You might get away without the control damper...
The key thing to remember here is that a burner can only be properly adjusted for one draught condition (assuming, of course, that it isn't self-adjusting!). Some seem to be more tolerant of variations in draught than others, but it can only be correct at one draught. Now if your draught in the chimney is varying, and there is no control for it... at least some of the time that burner is operating out of adjustment, and maybe way out of adjustment.
@ August 13, 2014 7:35 PM in Geothermal vertical loopsYour lake water heat exchangers are 10 to 12 feet down, so in the winter time they are in water which is about 39 F -- 4 C. In order to heat your facility, you need to extract the heat from the water in your loop going through the heat exchangers and raise it's quality (that's the job of the compressor). That's going to cool the water coming from the lake -- the heat has to come from somewhere, after all; there's no free lunch. So the return water to the lake is going to cooler than 39 F. Problem: you only have, at most, a 7 F temperature difference to play with (actually, you'd want to not use all of that -- say 3 F temperature difference, max.
Now the the heat which you can extract is a function of the temperature difference and the flow rate, just exactly like hydronic heating -- same formula. And, like hydronic heating, to get more heat you either need more flow or more delta T. You don't have the option of more delta T, so you need more flow.
I haven't seen your installation -- obviously -- nor have I seen the design documents, nor the controls. From the sound of things, however -- based on what you have written -- it sounds as though you need three things: more flow in the lake loop -- probably a lot more flow -- and, most likely, bigger heat exchangers in the lake; you are working with a very small delta T on those heat exchangers, so you are going to need to move a lot of water. You also need a control logic which cycles the compressors off when the temperature of the return water to the lake drops to some low value -- I'd pick somewhere around 35 F or 2 C as the minimum. That way you won't get the freezeups you mention.
@ August 13, 2014 3:53 PM in engineerthat small radiator at the end of the main to which you refer may be important for getting proper venting of that main. There has to be a way for the air to get out of the steam main -- either into the dry return to which you refer, or into the air.
@ August 13, 2014 3:50 PM in radiator steam traps vertical pattern single unionJoe, I love it.
You are right, though -- sizing the orifices is a bit of a hit or miss proposition, although there are sizing guides which can get you close.
In answer to the pressure question, you can make an orifice controlled system work on almost any pressure, believe it or not -- but it is much much easier to make it work on a very low pressure, such as you can achieve with a vapourstat set to cutout somewhere around 12 ounces or so, and cut back in around 6. That should be all the pressure you would ever need for this system.
@ August 13, 2014 3:44 PM in Geothermal vertical loopsLake Huron -- and Georgian Bay -- does sometimes freeze over. But it does not freeze to the bottom. As has been pointed out, at some depth -- and probably not that far down -- you will have lake water at a more or less constant 39 F (4 C). From this a properly designed geothermal system should be able to extract all the heat it needs to heat your property or, conversely, reject all the heat you need to manage to cool your property.
There are two approaches: a closed system, in which you have a system of pipes in the lake (probably at or very near the bottom) with sufficient surface area to extract or reject the heat needed, or an open system, in which you simply pump lake water through your geothermal system heat exchangers directly. Unless you are in a particularly grungy area of Georgian Bay, I would think the latter would work just fine.
So the question is -- why was the system unsuccessful? What, exactly, were the lake conditions which caused problems?
I have not drilled wells in the granite in that specific area (if it is granite?) but in general wells in igneous or metamorphic rock has rather poor yields, and may be quite unsuited for open system (pump the water out of one well and back into another) geothermal.
@ August 11, 2014 8:27 PM in One riser or two?they should both be 3 inch. As has been noted, two 2 inch are actually smaller in area than one 3 inch.
There is some advantage to having two, but on the 75 it isn't really necessary, provided that the rest of the header piping and all is correct. I'd put my effort into building a drop header for it, instead of going with two 3 inch -- you'll have better steam quality.