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Jamie Hall

Jamie Hall

Joined on September 16, 2002

Last Post on July 25, 2014

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very nearly

@ June 14, 2014 8:35 AM in Expanion rate

10 microinches per inch per degree F temperature change.  Depends a little on the alloy.  


@ June 13, 2014 7:20 AM in Union installation on 2.5"

It dawned on me -- at 3:30 AM -- that that's the way to do it.  Cut out a whole section.  Play with it.  Unions (or flange pairs) at both ends.  Just slip it back in.

Do I turn in my license now, or later?

Can you take

@ June 12, 2014 7:05 PM in Union installation on 2.5"

enough hangers off to get the pipe ends moved laterally enough to thread something on?

What a nuisance...

@ June 12, 2014 2:19 PM in Union installation on 2.5"

but, stuff happens.  Instead of making the final connection with a union, use a pair of flanges.  Cut the section out then proceed as you said at first -- nipple, T, nipple -- but on the end of that nipple screw on a flange, and thread and screw a flange on the cut end of the pipe.

Are you not able to drill and tap into the top of the pipe for the vent?  Is that why you need a T there?

The place I care for

@ June 11, 2014 10:24 PM in What are the implications of reducing radiator count on a one pipe steam system

has a long radiator made of two finned iron pipes under a big window seat -- the thing is 8 feet long, two pipes.  Approximate EDR 61.  It really works well.  The seat is at normal seating height and width.

Most likely

@ June 11, 2014 9:03 AM in Hoffman Boiler Feed, persistent trickle feed and overflow

that valve inside the tank.  The others just prevent backflow and reduce pressure, but don't turn the feed on and off.


@ June 10, 2014 8:33 PM in Hoffman Boiler Feed, persistent trickle feed and overflow

there is a shutoff valve in the mechanism -- not the pressure reducing valve, nor the backflow preventer.  It's that valve which is leaking and needs repair.  Find it and you'll be good to go.

How about...

@ June 10, 2014 3:24 PM in Radiators

"both"!  For a useless answer.  Or... "it depends".  Not surprisingly, there is a fair amount of radiation -- you can feel it if you stand near a warm radiator.  However, I believe that the major part of the heat transfer is by convection -- although I'll be the first to admit that I've not seen a really scientific study on that.  Rather, my opinion -- for that is all it is -- iss based on two things.  First is the plain geometry question: radiation operates only by line of sight to a cooler object.  Second is the observation that we rate radiation -- quite successfully -- based on the total surface area of the radiator, not on the flat plate area (which would apply to radiation).  For instance, a 10 section, 5 tube radiator of more or less typical geometry has a flat plate area of about 6 square feet -- but an EDR ("equivalent direct radiation") of 50.  Third is that it is quite possible to put a radiator in an enclosure and, provided the enclosure permits circulation, get almost as much heat out of it as if it were in the centre of the room.  Fourth is that you can put a radiator behind a couch (not touching!) and the room still is warmed -- but not that much the couch.

Now hopefully someone will come up with a genuine lab. study!

As I noted in my first reply

@ June 10, 2014 10:22 AM in Boiler replaced - Boiler trap removed

I think you are looking at a system which has had at least two stages of knuckleheads... if not more.

First off -- air vents of some kind, somewhere, are absolutely required.  In two pipe systems which have been "modified" over time, the easiest and most reliable approach to venting is good big vents at the ends of the steam mains and another set at the ends of the dry returns, just before they head down to the boiler.  The objective of the steam main vents is to allow steam to move rapidly to the ends of the mains, thus allowing all the radiation to start heating uniformly.  The objective of the vents at the ends of the dry returns is to allow the air leaving the radiators to go somewhere, and thus allow the steam into the radiators.

All this should happen at very low pressures -- a few ounces or so, maximum.

On residential systems, if is almost never necessary to have any kind of fancy gadget to get the return condensate back into the boiler -- assuming just one thing: that you have adequate (read: vaporstat) control of your pressure.  Gravity is astonishingly reliable, and all you need to do is give it a chance.  So yes; the ends of the dry returns should all drop down and join whatever wet returns you have before the wet return connects to the bottom of the Hartford Loop.

At this point it is worth wandering around in the basement and checking to see that all the wet returns are, in fact, wet -- that is, below the water level of the boiler.  Sometimes when boilers are replaced the water level is lowered, which can dry out some of the wet returns, with lamentable results.

The comment on the fancy gadget arises because in older, coal fired systems, there often was a fancy gadget at the ends of the dry returns (or sometimes elsewhere) to ensure that if and when the pressure rose to high that the condensate could get back to the boiler while at the same time still allowing air to escape.  They were needed because it was harder to control the pressure in a coal fired boiler; they don't turn off quite as neatly as oil or gas burners do.  There is no reason to take them off, however, if they are there -- but equally no reason to put them back on if they aren't.

Again, though, use a vapourstat for control!

As others have noted, the near boiler piping does leave something to be desired...

In response to direct questions: no, no check valves are needed.  Gravity will do the job.  At one time, there was some means for venting this system, which has been taken away.  The boiler return trap is not needed.  The two dry returns drop to the wet return before the Hartford Loop.

And, if you haven't already bought it, I highly recommend buying at least "The Lost Art of Steam Heating" available on this site.

That one's been around

@ June 9, 2014 9:17 PM in Two Pipe Steam System with Air Vents

for awhile.  But it's described in The Lost Art, of which I hope you have a copy.  What makes it a bit strange is the water seal in the "outlet" side of the "2 pipe" radiators (I like to think of them as 1 1/2 pipe...).

You have a really critical dimension here: the height from the steam main, where those returns tie in, in relation to the radiator.  On first thoughts (it's late at night...) you may have difficulties if that distance is less than about 28 inches for each pound of steam pressure.

I'll have to think about this one some more.  Meantime, go look it up in Lost Art...


@ June 9, 2014 9:12 PM in steam in the summer!

you are drawing hot water from your tank faster than your boiler is capable of making it.  Therefore the aquastat on the tank keeps calling for heat.  What is needed is a control on the boiler itself to shut it off when the boiler water reaches a reasonable high temperature, assuming that the thermostat isn't calling for heat.

Either that control is missing, or not set properly.

It's worth noting that you also have a capacity problem here -- you are drawing hot water faster than your system can make it.  Get the one problem fixed, and you may discover that you don't have enough hot water...

Is this thing

@ June 9, 2014 7:13 PM in steam in the summer!

set up as an indirect with circulation?  That is, is there a circulator taking hot water from the boiler, running it through a heat exchanger in the tank, and back to the boiler?  If so, something is amiss with the control on that circulator -- it should only run when the tank needs heat -- and there should also be an aquastat on that line, which turns the boiler's burner off when the circulating water is hot enough -- say 160 or so.

Or... is the tank simply storing hot water which is being created by the a domestic hot water coil in the boiler?  If so, again there should be an aquastat on the system which shuts the boiler off when the boiler water is hot enough.

Or at least that' the way I'd have it set up...

But it's basically a control problem.

You are indeed fortunate

@ June 8, 2014 7:33 PM in Steam Trap - Kelmac Jr. Retarder ?

to have that mercury vapourstat!  Those things are worth their weight in gold.  So long as they are levelled properly, they work really reliably -- for decades!

I don't think the bullhead T for the condensate returns is really going to be a problem.  Not ideal, perhaps, but not a problem -- the returns will be nowhere near full of water, after all.

I'd put two Gortons #2 on each steam main -- that will get the steam out to the end nice and fast and evenly.  Then I'd put one Gorton #2 on each of the returns if I could do it.  Otherwise, you could put one tap into the top of the T and then come off with a short 3/8" nipple, 3/8" T, and two short nipples and elbows going up to the vents -- sort of an antler.  That will work just as well.

Using the heat pump in the shoulder seasons is a good idea!

Sounds like you have

@ June 8, 2014 4:11 PM in Steam Trap - Kelmac Jr. Retarder ?

a pretty good plan there.  It will take some time to get the orifices "just right", but it's quite doable.

By abandoning traps, I presume that you will leave them -- empty or stuck open -- in place.  That will work fine with the orifices and low pressure.

You definitely want the vapourstat.  Without it it's pretty hopeless -- too much pressure.

On venting.  You will need main venting, and the more the merrier, on the steam mains.  It is possible, with care, to drill and tap 1918 black iron pipe.  It is a little chancier drilling and tapping 1918 fittings, as they are probably cast, and can shatter -- which is annoying.  However, a 3/8" nipple is fine for a Gorton #2.  You will also need to find a way to get vents -- again, the more the merrier, at the very least after the last radiator return into the dry returns.  At the boiler is better, but if not... anywhere after the last radiator return will do.  Without the steam main venting, yes you are depending on the air getting out of the mains via the orifices in the radiators, and that is going to be slow and uneven.

Not really

@ June 7, 2014 4:38 PM in Wife HATES old steam radiators. Don't care for covers. Alternatives?

Single pipe steam doesn't play well with baseboard type convectors (which don't play all that well with steam anyway), and they are close to your only real alternative.

However, it is a myth that radiator covers harm efficiency.  Some do.  But it is quite possible to have covers which impair the efficiency very little, and they can be quite handsome as well.

I, at least,

@ June 7, 2014 4:34 PM in Boiler replaced - Boiler trap removed

don't think you need a boiler return trap.  If a two pipe system is properly piped in residential sizes, the only traps needed are on the radiators.  I think you really need to think through the piping beyond the boiler -- as well as the boiler -- and see if you can figure out how it might have been piped originally.

There are several possible causes for the boiler running out of water after just a few minutes, but there are only two classes of them.  Either the pressure is much too high, and the water is backing out of the boiler and hiding in the returns, or the piping is seriously wrong with the same result or with the water being carried out into the mains.  Or some combination.  Check the pressure -- anything over two pounds is too much; quite possibly way too much.

I might add the contraption which was removed may not have been a trap of any kind.  If this was originally a vapour system -- which is quite possible -- there are any number of contraptions which fit your client's description which were not traps, but which served to make sure that condensate returned properly to the boiler.

From the sound of it...

@ June 6, 2014 4:28 PM in Boiler replaced - Boiler trap removed

this is at least a two phase, if not more, knucklehead job.  Which mean that getting back to where it should be may take some real detective work.

But fear not, it can be done.

First things first -- all that copper for the new near boiler piping is just plain wrong.  Whether the routing of the pipes is right or not is moot.  The material is wrong, and has to be replaced in threaded black iron.

Further, it has to be replaced in accordance with the diagrams and specifications from the manufacturer -- or better.  No compromises or skimping on sizes or dimensions.

Now.  That will give you a boiler, delivering steam through a riser or risers, to a header.  From that header one or more steam mains will depart, as well as an equalizer at the far end, which will go back to the Hartford Loop connection and from that down to the boiler return.  The steam main or mains will go out to the system, and a return or returns will come back and tie together before the Hartford Loop, come up to the Hartford Loop, and thence back to the boiler.

So far so good.  First question: is this one pipe or two pipe steam?  It makes a difference.  In either one pipe or most two pipe systems, there needs to be main venting at the ends of the steam mains.  In one pipe steam, there are also vents on the radiators; in two pipe there are not, but there are vents on the dry return(s).

In one pipe steam, condensate returns from the radiators to the same mains the steam came from.  In counterflow systems, all the mains slope down towards the boiler, but before they get to the boiler there has to be a drip connection from the main or mains down to a wet return.  In parallel flow systems, all the mains slope away from the boiler, and there is a drip connection down to a wet return at the far ends of the mains.  In these systems, no trap is needed anywhere on the system.

In two pipe systems, air and condensate comes out of the radiators via the return connections.  In most systems, there are traps on the radiator outlets to keep steam from getting out; in some vapour systems, there are no traps -- nor are they needed, as the pressure and sizings and fittings also keep steam from getting into the returns (provided the steam pressure is correct).  There is no steam in the dry returns, and hence there is no need for a trap on the dry returns.  Nor is there a need for a trap or check valve on the wet return.


Where are we?

I would be helpful to have some pictures of the near boiler piping -- even if it all has to go -- and a diagram of the rest of the system.  Also, of course, whether it's one pipe or two...

We look forward to that -- then we can probably help a lot more.


@ June 4, 2014 10:45 AM in piping

will keep the piping nice and clean and corrosion free.  The only place you may have to worry is on wet returns, which should be inspected from time to time.  Even there, they are much more likely to corrode from the outside in, rather than the other way.

Yes, copper is better

@ June 4, 2014 10:43 AM in Forced air

in my humble opinion -- if only because it doesn't need as much support.  That said, I use PEX in applications where it is difficult to "thread" copper into an existing chase, or where copper solder joints would be very close to old wood (fire hazard).  Both of which are problems in the building I superintend and maintain...

A true

@ June 3, 2014 8:11 PM in Power transient freezes Lochinvar Knight controller

computer/high fidelity grade UPS is the answer to this one.  True, there is an efficiency loss -- but the connected load (your Lochinvar) never sees anything except the sine wave produced by the UPS.  The UPS takes whatever is coming into it and charges a battery -- filtered DC.  The output from the battery (still DC) is inverted, crystal controlled at 60 hz, and delivered to the load.

Cheap?  No.  Sorry about that.

Effective?  Yeah...

I'd use

@ June 3, 2014 4:27 PM in Forced air

the same closed cell foam snap on stuff I'd use for any hot water pipe...

Main thing with PEX and hot water is support -- the stuff sags like crazy when it gets hot.  I might even put it in a tray.   But you probably know that...


@ June 3, 2014 4:24 PM in Gas forr a Vaccum Vapor System

There really are only two, but they are both critical -- especially on vapour systems.

First, the piping diagrams in the installation manual are minimums.  Absolute minimums.  Don't cheat.  Keep all the piping as shown or larger and/or higher.  Install a drop header if you can; they help a lot.

And be sure to use threaded black iron.  Don't use copper!

The second is the water line: you must keep the new waterline within an inch, up or down, from the old one.  Put the new boiler up on blocks if you have to, but keep that waterline where it is.  Vapour systems commonly have wet returns which must be kept wet, or they will work poorly if at all -- and changing the waterline is lethall.

Other than that... the obvious: size the boiler properly, by installed EDR.  Also, use a vapourstat for control, not a pressuretrol (or in addition to a pressuretrol).  Set it at no more than 12 ounces to begin with for the cutout.
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