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Jamie Hall

Jamie Hall

Joined on September 16, 2002

Last Post on August 21, 2014

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@ October 30, 2009 12:53 PM in expantion tank

200 psi?  Why I prefer steam...  But yes, somewhere in the system there has to be room for the water to expand, which means somewhere in the system there has to be air, or access to air.  I must admit that one something like that system, I would put the expansion space or tank at the top, however, not at the bottom.  In fact, I would be very much inclined to go for a big tank at the top, vented to the atmosphere.  But that's just one man's opinion...

Whoever invented

@ October 30, 2009 8:50 AM in Boiler system return flow problem - circ location?

the SawZall was a genius...

But to answer the specific question, yes that circulator is on the wrong side of the T, and yes it will kill any circulation there might have been in that far flung branch...

It's both

@ October 29, 2009 2:36 PM in main vent location

the blast of steam -- and the slug of errant condensate.  The location you describe is pretty safe, on the whole, but I'd still put in a short nipple if I had the overhead room.

Only thought I have

@ October 29, 2009 11:00 AM in one pipe steam system ,boiler replacement

is that while you are nursing the old girl along, might as well spend a little time getting to really know the rest of the system and bringing it right up to snuff!

Most thermostats

@ October 29, 2009 8:55 AM in Thermostat difference setting

at least the digital sort don't have a differential setting, as such.  The older mechanical ones didn't, either -- they used an anticpator (simply a little electric resistance heater) which had to be set for your particular installation.  Typically, though, they will look for half a degree rise or so between on and off, and also typically they will turn on when they reach the set temperature.

You do need to set the cycles per hour, though.  Steam or gravity hot water is typically one cycle per hour.  Other systems are different.

There is a differential on the vapourstat, though, usually subtractive.  If you set the cut out at, say 10 oz. per square inch and the differential at say 6 to 8, you should be fine, at least for starters...

Apples and Oranges

@ October 28, 2009 7:18 PM in Vapor system conversion to hot water condensing boiler

This is a very old debate.  Steamhead, however, is correct in one major point: you simply cannot make a valid comparison of heating systems unless all the variables are controlled -- and, preferably, the same.

That is to say, if you are to compare fuel use in a building (or efficiency comparisons between heating systems -- same thing) you simply cannot come up with any valid comments unless all the systems are in the same state of repair (and I've seen some of the old steam systems in Montreal -- they're really bad) and, if you are working a before/after, all other changes, such as insulation, storm windoes, and what have you are accounted for.  If you do that, rather straightforward engineering analysis will show that the variations in efficiency lie in the boiler, and that if you can run a condensing hot water boiler so it condenses (which you can't, all the time), you will get slightly higher efficiency and thus slightly lower fuel use.  It amounts, from my research, to a maximum of about 8% for equally high quality units with one condensing and the other not.  The heat transfer medium -- steam, water, or (shudder) air -- makes no difference at all, provided each system is equally well designed and maintained.

Then the remaining questions have to do with the equally well designed part and the maintained part -- and in my opinion most of the older steam systems were very well designed indeed, much better than some of the newer hot water systems I've seen.  It is quite true that some of them were designed for greater heat loads than are now present in the building, but by no means all of them.  And in any event that simply means that the boiler won't have to fire as long to keep the temperature up.

The other biggy is the cost of conversion.  If one finds that one can use all or most of the old piping, and all the old radiators, then the conversion isn't all that expensive -- although you will never get it back on the energy savings.  On the other hand, if one finds that parts of the old steam system won't take 30 psi, and you have to rip the whole thing out...

To me it isn't a philosophical thing, it's pure dollars and cents.  Getting a good steam system, which hasn't been completely trashed by some gorilla, back up and running is cheaper than conversion.

Steam can't

@ October 28, 2009 11:31 AM in radiant radiator with no vents?

force it's way in unless the condensate and air can find an easy way out.  Before trying to take that tap out (and possibly breaking something -- but try either 3 in 1 or WD-40 on it) see if you can figure out why it's working -- after all, if it's working, why fix it?

Yep, that's how you do it

@ October 27, 2009 7:21 PM in boiler won't reset

but, unless you are a trained oil burner tech, and know how to correctly purge the fire box and reprime the pump...


The level of disaster which WILL occur if you don't know exactly what you are doing ranges from badly singed eyebrows to pieces of house all over the neighbourhood.

Oh clearly

@ October 27, 2009 4:59 PM in Vapor system conversion to hot water condensing boiler

the old boiler will have to go -- no question about that.  That's kind of a given. 
And it is possible that some of the "upgrades" will have to be un-upgraded too, unless they were done with the VECO system in mind (unlikely).  The poor maintenance will be mostly a problem with the boiler -- which is going anyway; the rest of the system doesn't need much in the way of maintenance anyway.  As a sort of general rule of thumb, the most likiely place for a problem is in the wet returns, which do corrode with time.  Otherwise there are plenty of steam systems out there working on their second century!

Be very careful with that pressure test.  It is very hard to pressure test a steam system, as the working pressures involved are so low -- never ever more than 3 psi at the boiler, which pretty well means air, and  sensitive gauges, nand temperature compensation.  Can't do it with water.  Anything over 3 psi and you will have to replace the vents, whether you want to or not (they can't take it) and you may well break loose things elsewhere which wuld be just fine for steam.

You should be able to get at least 83% efficiency from a steam boiler.  In fact, on a new install, properly adjusted, you may well see a good bit more than that.  Steam boiler makers tend to be conservative on their specs.

I'll still hold by my original comment: get a good new boiler, properly piped and installed (that means good near boiler piping, match the water line of the new boiler with the old one, even if you have to mount it on a pedestal or something, make sure the controls are correct (use a vaporstat, not a pressurestat) and set properly -- then set about bringing the rest of the system up to snuff.  In my opinion, you'll be much better off in the long run doing that than trying to convert to hot water.

There is no good reason

@ October 27, 2009 9:41 AM in Retrofit old steam system

other than efficiency to not have a steam boiler in a different building from the one you are heating.  Think of all the central steam heat systems there are, all over the country!  However, if you are going to do either steam or hot water -- it doesn't matter which -- and run the lines underground from one building to another, you will want to take major precautions against heat loss.  You could do a cost-benefit on options, but in my humble opinion, the best approach would be to run the steam (or hot water) lines and returns inside a separate duct, rather than directly buried -- and insulate the dickens out of them.  I'd go with 2" on the feeds, and 1" on the returns.  I would place insulation over the top of the duct -- again, 2" -- and extending out at least as far to each side as the depth of burial.  Overkill?  Not in Alberta...  You have the advantage with a duct, too, that you can run the power and control lines for the boiler in the duct as well (at least I think the Canadian electrical code permits that; I'd have to check).

Got to admit I wouldn't do it -- but then, it pays to remember that the client is always right...

On the other set of topics -- it will be more satisfactory to reinstate the steam system.  There is no reason at all why the risers -- if they were in use only a few years ago -- or the radiators should give any particular problems (I have seen buildings where steam was supplied to a system which had been off and abandoned for 40 years -- and it worked fine from the get-go).  That will be much easier than trying to convert to hot water.

I is almost impossible

@ October 27, 2009 9:27 AM in vapor vacuum heating co. Philadelphia

to vent mains too rapidly.  Radiators, yes -- but that's not the case here.  The main vents really do two things: let the air out of the mains, and let the air from the radiators out of the mains.  On systems of this sort, there really is no need for there to be main vents on the ends of the mains -- provided that there is a way for air in the mains to get back to the main vent(s) at the boiler.  That means that there are dry returns, as well as wet returns.  If there are no dry returns, then there must be main vents at the ends of the steam mains (otherwise, where is the air going to go?).

It is possible that the system never did have wet returns; some don't.  If the dry returns are pitched to return to the boiler, they will carry the condensate back to the boiler quite happily -- as well as the air.  One possible problem, though, is that if the pressures are too high you may get steam in returns, which will pretty well stop any heating (as well as possibly holding condensate back, which may cause a water line or flooding problem in the boiler).

Since it is unlikely that you can raise the new boiler so that the water line is where the rest of the system wants it to be, can you pipe in a false water line arrangement at the boiler instead?  That might help a lot, and save the trouble of lowering all of the returns.


@ October 27, 2009 9:16 AM in help - hammer in radiator

If the replacement valve is either designed or installed in such a way that water can't drain completely -- really totally completely completely -- it's going to hammer.  Make sure that when the valve is open, the passages have at least the cross section area as the pipe, and that there are no obstructions to water flow (for example: is the seat design such that it can't trap any water?).  Not all valves are created equal (and it's no comment on either design or construction -- there are some very high quality angle globes available which simply aren't suited for one pipe steam).

Once that's checked, make sure the valve is fully open -- but you knew that!

And if it is still hammering, come on back and we'll all think some more!

Why oh why?

@ October 27, 2009 9:09 AM in Vapor system conversion to hot water condensing boiler

The VECO system was -- and properly maintained, is -- one of the nicest and best ways to heat a space that's been built.  And maintenance for it is very minor -- you don't even have radiator traps to worry about!

Why not save a bundle of money and just get the system running the way it was supposed to?  If you are concerned about the difference in efficiency between a top end mod-con hot water system, with all the bells and whistles, and an equally top end new steam boiler (they cost, at worst, about the same -- and then the mod-con needs pumps and expansion tanks and all that on top), don't be.  A little quick arithmetic will show that the best you can do is save (using oil as the example) 6 to 8 gallons of oil per hundred gallons at the most.  Not putting too fine a point on it, you would be better off investing the money you would have put into the conversion into a CD somewhere- even if you don't have any problems.

Then, as Nicholas pointed out, you will probably (although not certainly) have problems.  The steam system and all its parts was built to run on somewhere around 10 to 12 ounces per square inch of pressure.  A hot water system must run on somewhere around 20 pounds per square inch, or more.  You may get really fortunate, and not have any leaks.  Then again...

Next, keep in mind that the pipe sizes and layout which are suitable for steam are a kludge at best (and unworkable, most of the time) for hot water.  To achieve anything like the efficiency noted above, never mind even heat, you would be well advised to completely re-pipe the system.  Don't even try to use the old steam pipes.

On the other hand, you could move to a nice new steam boiler, make sure that your VECO system is operating the way it is intended to operate (check things like venting, water levels in the new boiler, operating pressure, etc.), save a bunch of cash, and have one of the best heating systems ever made.

Your choice, I guess...

real simple

@ October 26, 2009 8:55 PM in How does a pressuretrol control the steam pressure?

a pressuretrol is just a switch, connected to a pressure sensing element -- diaphragm or bourdon tube.  At some point, as the pressure rises, the element flexes enough to open the switch -- which turns off the power to the burner.  Then as the pressure drops, the element flexes back, the switch closes again, the burner turns on again (assuming the thermostat still wants steam) and the cycle repeats until the thermostat is happy. 

oh yes

@ October 26, 2009 8:50 PM in Mike Mulligan and his steam shovel

my parents read it to me, I read it to my kids, and... hopefully!  A lovely lovely story.

May I add a comment?

@ October 26, 2009 3:39 PM in A suggestion for contractors

for the contractors: you don't have to post on the Wall, just because you are listed in Find a Pro.  You don't even have to read it, if you don't feel you have the time.  I can understand a concern about free advice and liability and all that.  But Dan is right -- there are a lot of homeowners and building supers and other sundry individuals who use this site, and would be delighted to have a pro. in their area come up when they look for one...

Probably not

@ October 26, 2009 12:45 PM in Where Did My Water Go?

The amount of water you've apparently lost is more than I would expect the returns to hold -- by a considerable margin.

And Steamhead's probably right.  If I were a gambling man, I'd bet the floor was dirt originally, and got the concrete poured over it.  I've seen a bunch of those.  Which leak...


@ October 26, 2009 12:42 PM in Advice on Floor Indirect Radiator

where would the indirect get it's air from?

Other than that, mounting a radiator horizontally shouldn't be a problem, provided -- and it's a big provided -- that it is mounted in such a way that condensate can drain out of it.  If it can be oriented so that you have an outlet at the lowest point, it should work.  Orientation won't affect the heat output, provided, as I say, it can drain.

A good place to start

@ October 26, 2009 12:37 PM in boiler water line

if you don't have them is Dan's books, available on this site (I sound like an advertisement... but they really are worth it!).  That said...

A very common problem in the type of retrofit you did is that water line.  It is not at all unusual to have the end (or sometimes elsewhere) on the steam mains drop to a wet return, and to have the ends of the dry returns drop to the same wet return.  If the water line is too low, there is no water seal between the to and steam gets into the dry returns -- presto, no heat.  The easiest solution, as you note, may be a false water line, since it sounds as though putting the new boiler up so that the water lines would be the same would then require a ladder for servicing!

Second, there should be no need for a vent on a two pipe radiator, although it won't hurt anything.  The air and condensate should go out -- usually through a trap, but sometimes through an orifice or other seal -- into the dry return; the air then goes to a main vent, and the water back to the boiler.  If the return from the two pipe radiators is yeouch hot (not just warm) you may be getting steam into the return through the radiator, which is another way to shut down a two pipe system.  Depending on the type of system, you may need to throttle those radiators which offend, or replace the trap or whatever to bring them back to design.

A one pipe radiator which doesn't heat isn't getting steam (yeah, I know, that's one of those remarks.  Oh well...).  Either the air isn't getting out -- bad vent -- or there is something, such as a sag or a badly pitched pipe -- which is letting condensate block the flow.  Or even a bad valve!  Or one which doesn't belong.  I would trace out the riser to those radiators when the system is running, and see how far along steam is getting -- that may produce a hint as to what's wrong.  Same sort of logic applies to a two pipe radiator, except for the vent.

Do not check a one pipe radiator's vent by removing it when the system is running -- if it is the vent, you'll get steam out of the resulting hole, which can burn very badly!  Also removes wallpaper...

Check your system pressure -- no more than a pound an a half, and less (say 10 to 12 ounces) is better, if your controls will let you do that.

Just a few thoughts -- by no means exclusive!

Er... blurp

@ October 24, 2009 6:06 PM in Where Did My Water Go?

losing that much water sounds to me like a honest to gosh leak in a wet return.  Under the carpet.  Under the concrete.  Sob.  Without knowing exactly how your system is hooked up, I can't suggest the best way to find it... maybe someone else has a bright idea?


@ October 24, 2009 6:02 PM in vaporstat

L408A, break on rise

Not normal!!! TURN IT OFF!!!

@ October 24, 2009 3:34 PM in Steam heater

Be happy that your pressure relief valve is working properly, because something else most assuredly isn't.  A residential boiler should never, ever go over a few psi (most fittings, valves, etc., are rated around 3 psi, with a never exceed of 10).

TURN OFF THAT BOILER NOW, with the emergency switch, and get a pro in there, pronto, to find out what's wrong.  I do not want to sound alarmist, but if that safety valve happened to stick shut, what you have could launch your whole house into low orbit.