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Jamie Hall

Jamie Hall

Joined on September 16, 2002

Last Post on April 24, 2014

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The simplest way

@ March 16, 2014 8:02 AM in Excessive Makeup Water Use/Proposed Elimination of Condensate Return Tank

to handle this is going to be to replace the condensate return lines as low as you can get them to go -- the whole length of them.  They can be done in copper.  As I understand it, you do not have dry returns -- just a pair of parallel flow steam mains, with drips which go to the wet returns.

It is quite likely that when the boiler was replaced, the water line of the new boiler was below that of the old one, which makes your height margin on the wet returns a bit small -- but so long as they are really truly below the boiler water line, you should be OK.  It doesn't take much -- a few inches is ample.

So long as those wet returns are, in fact, wet, they don't need traps.

And you don't need the condensate return tank and pump.

With regard to Question 5 -- all of the lines need to be below the water line.  And indeed there is some water stored in there, but that isn't a problem.

Not that I really need it...

@ March 15, 2014 7:42 PM in A challenge...

We have Cedric so closely dialed in that it really would be superfluous...

Hadn't really paid attention

@ March 15, 2014 7:35 PM in Question about two pipe system

to this thread.  Sorry...

I'd be very very interested in where the water line was on the original boiler in relation to where it is on the new one.  That particular Weil McClain has a water line which is rather low to the floor, relatively speaking, and I'd be willing to lay dollars to doughnuts that the old water line was significantly higher.  if so, part of your problem may be that some of the piping which was below the water line before isn't below it now -- and that can cause no end of problems.  it can be fixed, but it needs to be.

There is some slightly unusual piping associated with the header...

Broomell systems run on very low pressure.  Are you using a vapourstat for control?  You should be.

Yes and yes

@ March 14, 2014 6:50 PM in Natural Gas to LP gas conversion .. orifices

I am no gas expert, but I do know that anytime you change an orifice size -- or a nozzle for oil -- you have to adjust the air as well.  And that goes double for changing from natural gas to LP; they have very different air requirements.  Assuming that the rest of the system is correctly set up for LP (keep in mind that there may be other components which should have been changed, in addition to the orifice) you have to set up the system with the proper test equipment.  No shortcuts.

Ought to work

@ March 14, 2014 6:48 PM in Want opinions on thermostat location

I don't think the B vent will hurt it much -- there seems to be enough air in there.

May I add one more thing

@ March 13, 2014 8:04 PM in converting oil burner to gas

to the general question which has come up on this thread?  This is the little matter of warranty.

If you boiler is installed and set up precisely as the manufacturer suggests, it is likely that the boiler warranty will be valid.  At which point, if something goes wrong, one can hope that a) the manufacturer will make good on the warranty and b) that they have a rep in your area who is reasonably competent.

Now if you get in someone like Tim -- or one of the folks he mentions -- you have a different matter: your installer is standing behind the installation.  If he is a good honest man -- like Tim! -- and something goes amiss, it will get fixed, and fixed right.  In other words, your warranty becomes the person.

To me, at least, personal integrity coupled with competence and experience is worth at least as much as a piece of paper with fancy scroll work on the edges!

It could very well be

@ March 13, 2014 7:54 PM in Steam coil sound

operating correctly; at 50% it is likely that less steam is getting in than can be condensed, and thus all the trap will ever see is warm condensate.

The tinkling sound could be almost anything -- possibly water dripping, but it is also possible that it is an expansion sound of some kind.  Does this thing have fins?  They often ring just a little bit.  Can be very exasperating to find, never mind fix!  And I have no suggestions other than listening carefully... or ear plugs!

First step

@ March 13, 2014 7:50 PM in General steam trap question

is going to be finding out if the traps have failed.  They can fail in two ways: either stuck open or stuck closed.  If they are stuck closed, it is likely that the coil won't heat, or will heat very poorly (relatively speaking, that is).  If they are stuck open, the problem is that steam can get by them on longer heating runs, and build pressure in the returns -- which will cause other units on those returns to not heat properly.

If they are stuck closed, the only real recourse is to repair them.  As NBC suggested, is there any hope of reaching them with an extension on a socket wrench?  Bit cumbersome, but might work.

On the other hand, if they are stuck open, it might be possible to cheat.  Cheating, in this instance, means going back even earlier: if there are inlet valves on those units where they are failed open, and those valves are capable of throttling, and your pressure is low enough (that is important!) you can partially close those valves to simulate having an orifice on the inlet, restricting the steam flow to just that which can be condenses in the unit, leaving none to escape.  Might be worth a try...


@ March 12, 2014 10:13 PM in Help! Left water on filling boiler and now...

Mine is none too good -- I'm 72 -- but there are no bladders in a steam boiler, or anywhere else in a steam system for that matter.  That remark by your plumber does not inspire confidence...

However, it could very well be the pressuretrol.  It could also be the vents.  Enough water pressure to come out of a vent up in the house could very well have damaged any or all of them...

Keep us posted!

Not as you are leaving...

@ March 12, 2014 7:17 PM in water in tank

when you have just finished cleaning yourself up a bit and are getting in the truck...


@ March 12, 2014 7:10 PM in How to detect if there's oil in steam boiler water

when in the cycle does it "short cycle"?  It is, as Fred said, unusual for oil -- even a fair amount of the stuff -- to cause a problem with the pressuretrol.

You have a real problem...

@ March 12, 2014 7:07 PM in Help! Left water on filling boiler and now...

You don't know what your system is doing, and that could be quite dangerous.

However, I would ask one real fast question: what does that pressure gauge read when the system is more or less cool?  If it reads 0, or nearly so, and then scoots up to 10 when the boiler starts firing, it may be correct -- and that's not good, as the pressuretrol should shut things off long before then.

Bottom line on that: either the gauge is bad or the pressuretrol -- or, as has been suggested, the pigtail or the entrance to the pressuretrol is plugged.

I would be very hesitant to run the system at all until I could be reasonably sure that the pressuretrol was working the way it should.  The only real alternative I see for the time being is for you to assume that that gauge is correct (but check that 0!) and play pressuretrol yourself, turning the system off when the pressure rises and back on when it comes down again.  Again I say I don't recommend doing this; you'd be being a test pilot for an unknown configuration -- but it's the only thing I can think of until you can get a steam guy in there.

If you can keep the house above freezing in some other way WHICH IS SAFE, I'd do that instead.

Of course

@ March 12, 2014 11:34 AM in Boiler efficiency cycling vs continuous run

you all are quite correct -- so long as the pipes and the boiler itself are within the more or less heated envelope, the "loss" isn't actually a loss in terms of overall heating efficiency.  How much these heat transfers -- to avoid the term loss! -- contribute to the comfort of the house is another matter, and one completely dependent on the structure.  This is one of the many reasons why trying to pin down the "most efficient" way to operate a heating system is so darn difficult!

The only real total loss is the heat in the stack gas, and even then only to the extent that the stack is not part of the heated space.

Same thing is true, of course, of the water heater and the hot water pipes -- in any climate where heating is used much of the time, the "losses" from the water heater and the pipes isn't really a net loss.

As for the pumps and fans -- quite right there.  They do use a surprising amount of energy, which is conveniently overlooked by the folks (including the government boffins) pushing high efficiency hydronics, radiant, and particularly hot air.

All of which is why, although steam is sometimes given a bad rap (the best we can do without heat recovery heat exchangers on the stack gas being in the high 80s) the overall efficiency of pretty much any of the various heating systems is within a very small number of percentage points, provided they are all maintained equally well -- a rather big if.

I like to look at it this way...

@ March 11, 2014 12:42 PM in Boiler efficiency cycling vs continuous run

You need to deliver a certain number of BTUs to your heated space.  To minimize parasitic losses -- heat lost from the steam mains, lost by radiation from the boiler, etc. -- you'd like to do that in as short a time as possible.  However, the radiation can only deliver heat at a certain maximum rate -- so there is a minimum time which the radiation must be at steam temperature to do the job.  The problem arises when the boiler is delivering steam faster than the radiation can condense it.  Then you have to shut the boiler off long enough for the radiation to catch up -- but no longer.  Then run just long enough to fill all the radiation again, and so on.

The last thing you want is for the system to build pressure beyond what is needed to gett the steam to the radiators -- a pound or so at the very most in almost all cases (a few ounces for vapour systems!).  An ideal system would modulate the heat output of the burner to maintain just enough pressure to keep the steam moving; that's what the old coal burners did (but not very efficiently!) by varying the draught.  Instead, almost all residential systems modulate the heat output of the burner by turning it off and on -- and in most systems which are running well, the off time is limited by the burner itself!  Many power burners and oil burners have pre and post purge cycles, which are often plenty long for the pressure to drop to the point where the vapourstat or pressuretrol will cut back in.

It's not that intuitively obvious...

Sounds like

@ March 11, 2014 12:30 PM in Not enough heat with new boiler set at low pressure.

two unrelated problems.  First, as NBC says, your main venting needs to be checked.  If there is a big difference between when heat first appears at the first radiator and when it shows up at the last, that's a big part of your problem.  Get that fixed and then you can start adjusting the radiator venting -- but not before.

Second, you mention something about 10 minutes a cycle.  That's way too short for steam, and may indicate that your thermostat isn't set properly for steam heat.  If it's got a cycles per hour setting, make sure that that is set at 1 cycle per hour; most thermostats come from the store set at 6, which is wrong for steam.  If it's got an anticipator, try setting that so you get a longer heating cycle.  If the boiler doesn't run long enough, there's no way it can get heat to all the radiators before it quits.

I wouldn't recommend it, but...

@ March 11, 2014 12:26 PM in Converting one pipe steam to hot water!?

if the client is really interested, there are several things to consider.

First: will the radiators (particularly if it's two story, the ones on the first floor) take the pressure?  10 to 15 psi is a lot different from 10 to 15 ounces.

Second: Is there enough radiation?  This is particularly true if you are thinking of trying to run in a condensing mode.  That handout has the BTU per square foot figures for radiators; note that that temperature is the average of the inlet and outlet temperature, not the inlet temperature.

Third: you will have to run one new pipe to each radiator; you'd be well advised to run all new piping, as the odds of the steam piping being arranged for decent hydronic work are slim to none -- even if it doesn't leak.

That's for starters.

Your client will not save money.  She would be much farther ahead in that regard bringing the steam system back to operating as it should and, if necessary, installing a nice new gas fired boiler.

Exactly, Neil

@ March 11, 2014 8:59 AM in Boiler efficiency cycling vs continuous run

If the boiler is sized to exactly maintain the setpoint temperature difference -- say 70 inside, 0 outside -- and something happens to drop the inside temperature -- say someone sets the thermostat to 60 for a day -- the boiler cannot bring the temperature back to the setpoint.  Close, yes.  Give it enough time you might not see the difference.  But actually get there?  No.

Mark S has an excellent point on the efficiency loss from heating the steam pipes and radiation (not to mention the boiler and the water) after the burner has been off.  This is why I disagree with the theory of "let the latent heat do its work".  If you are dealing with the typically slightly oversize boiler, and are at the point where the thing is cycling on pressure, you want the off part of the cycle to be as short as possible, to minimize these losses.

A related question is the question of how many cycles per hour do you want to have.  That's really system dependent, but even in very cold weather most systems will have cooled enough in a half hour or so that there is no real additional loss in going out to an hour.

And yes, Mark, the thermodynamics involved is messy! 

In principle...

@ March 10, 2014 9:09 PM in Boiler efficiency cycling vs continuous run

you are basically correct.  A setback should save energy.  In practice, the amount saved is small enough to get buried in the noise, at least for reasonable setbacks on a daily basis (the actual energy used, all else being equal, should be related to the time weighted average of the upper and lower setbacks -- thus if you run 12 hours at 60, and 12 at 70, in principle you should see the same energy use as if you ran all the time at 65)(in practice, the whole thing is vastly more complicated -- if only because outdoor air temperatures aren't constant).

On the question of recovery, though... let us suppose, for the moment, that in fact the system is exactly sized to the heat loss at the design temperature, and that we are enquiring about steady state outdoor conditions (never happens, but what the heck) and recovery from a ten degree setback.  Now the rate of temperature rise will be proportional to the excess available heat, which in turn is proportional to the difference between our target indoor temperature and the current indoor temperature.

If we do a little mathematical magic with that -- which we needn't put down here, if only because I haven't any idea how to write the equations in a comment box! (hmm... come to think of it... the basic equation is dT/dt = K(Tdesign - T), where dT/dt is the rate of change of temperature with time, K is a constant depending on the structure, Tdesign is the design or target temperature and T is the actual temperature and time t) -- we find that the time required to reach the indoor design temperature is... infinite.  That is, we will never quite get there.

One of the minor beauties

@ March 10, 2014 8:53 PM in fuel cell

about fuel cells is that they don't produce much heat.  So the question might be asked, how are they proposing to supply heat to their HVAC?  Or is this in some southern clime?

There is a downside... a, those puppies don't come cheap and b, they do need fuel... and unless they are hydrogen cells, they don't do anything different environmentally than a good clean burning gas boiler or oil boiler (depending on the fuel).

If they want to go off grid, they'd be much better off (unless their heat loads are very small) to go with a natural gas (if available) or diesel co-gen system.

If their budget is anything like most churches, they'll be putting in a boiler, as Icesailor says!

But there's one in every crowd, I guess.

At the risk of sounding flip...

@ March 10, 2014 6:56 PM in Repiping options

whichever is going to result in the simplest installation with the correct pitches!

Well now...

@ March 10, 2014 5:58 PM in Boiler efficiency cycling vs continuous run

Depends a lot on what you really mean by cycling If we confine our remarks to the cycling which a steam boiler which is slightly oversize will do at the near the end of a long cycle, cycling off on pressure so that the radiation can catch up to the boiler, then the answer is yes, there is a small loss in efficiency.  Emphasis on small.  If the off period is short -- typically just long enough for the burner to shut down and restart, the loss is very small, as the boiler and the piping never really cool down at all.  If the off time gets longer, the efficiency starts to suffer, as it is  necessary to bring things back up to temperature.

At a guess,

@ March 9, 2014 6:02 PM in how to get rid of boiler solder smell?

the only way you will ever get rid of the smell is to drain and flush -- and drain and flush... rinse and repeat... until it goes away.

Which the leak won't, by the way.  It may have stopped for the moment, but it's odds on that it's going to open up again.
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