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Jamie Hall

Jamie Hall

Joined on September 16, 2002

Last Post on September 15, 2014

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It makes a certain amount of sense but...

@ July 5, 2014 8:57 PM in Mixing valve and check valves

it could also be the mixing valve trying to backflow.  It's happened.

On whether it's required.  I don't know what code you are working with, but the code which I used to work with and enforce, when I did such things, required a reduced pressure zone backflow preventer between any domestic supply and an irrigation system.  Further, if the doggy wash does not have an air gap from the fill, or if there is a hose and spray attachement, it would require an RPZ on both the hot and cold lines.

Even if it isn't code where you are, in my humble opinion it's a very very good idea.  A check valve does NOT qualify as adequate protection.

Much as I dislike regulation...

@ July 4, 2014 7:43 PM in stupidity

OSHA has some regs. on working in hot conditions.  Mostly it's common sense (which seems to be anything but, as your tale shows) -- plenty of water.  Maybe electrolytes, but I go easy on those.  And most of all limited time in hot environments; OSHA has tables for that, and the amount of rest required between.  The .pdf from this link is useful:

You did the right things!  Your boss?  Not so much so.

True RMS

@ July 3, 2014 2:20 PM in True RMS

should be a measure of the average voltage or current, over time (usually a very short time -- one cycle!), being measured -- as opposed to peak voltage, which would be the highest voltage.  It's really only of concern with alternating current or rectified alternating current without capacitors, filters, chokes and sundry other bits used to smooth out the voltage or current.  In alternating current, for example, the true average voltage or current is zero -- since half the time it's positive and half negative.  Not a very useful result...

Do you need it to troubleshoot HVAC equipment?  I doubt it, so long as you meter has some way to measure AC at all (and I've yet to see a multimeter which didn't).

It's actually not all that simple to build a circuit which will measure true RMS.


@ July 1, 2014 5:44 PM in Moving a radiator to put floor down

that you are planning to disconnect them, your best bet is a heavy duty furniture dolly.  They have casters on all four corners, and you would raise the radiator up, balance on the dolly -- they're pretty good size, so that's not hard, wheel it out of the way, then bring it back.

Rinse and repeat.

That said... that floating floor is going to raise the radiators.  Be sure and check to see that they can, in fact, be reconnected without too much trouble, and that the pipe pitches will still be OK.

The proposed solution

@ June 30, 2014 9:30 PM in Two pipe: concerned about one radiator

may -- or may not -- work.

In fact, the whole radiator may not work as well as it should -- I would expect the trap to close way too soon.

However, leaving that be, if you are getting hammer on it -- even rather mild hammer -- I would check the size and pitch of the runout from the main to that radiator.  If it is sized and pitched as though it were one pipe steam, rather than two pipe, then condensate will have a chance to get back down that feed to the main, and thence back to the boiler.  Not the ideal solution, but it should work.

MTBF figures

@ June 29, 2014 12:23 PM in need electrical help

would be interesting.  I've never seen any...

My preference for 120 volt safeties isn't based on that, though, but on a desire to kill the mains power feed to the unit if a safety trips -- as distinguished from a true control, such as a thermostat.

As to the durability of the switches.  As someone further up the thread noted, it is more difficult to make a reliable low voltage dry contact than it is to make a high voltage one, simply because for a given contact resistance the low voltage circuit if more affected.  Which is not to say it can't be done -- there are millivolt switches which can withstand a million cycles.  They will cost a little more, however (until you get up to even higher voltages -- 660 and up -- where you need auxiliary contacts and arc suppressors and things begin to get actually interesting).

Bottom line on that -- if you can't find a mercury switched thermostat, vapourstat or whatever, you're stuck with the dry contacts and you're pretty much at the mercy of the bean counters at the manufacturers!

Leave all the factory wired

@ June 29, 2014 11:33 AM in need electrical help

24 volt stuff alone.  As has been noted, warranty issues.  However, that doesn't prevent you from putting anything you want into the 120 volt feed to the unit from the switch box!  So... you have your regular cutoff switch somewhere, then in series to your new second LWCO, then in series to the second pressuretrol, power the automatic water feeder off all that if you like, then -- finally! -- to the power input to the boiler.

I'm paranoid

@ June 27, 2014 10:03 PM in need electrical help

and I don't want any chance of something turning a system on which a safety has turned off.  I want power removed from that puppy until I find out what's wrong.

In most cases

@ June 27, 2014 8:09 PM in need electrical help

(check the ratrings!) the best way to wire safeties is in series with the 120 volt feed to the boiler controls.  On the hot side of the 120 volt (never, ever, put a switch of any kind in either the ground or the neutral!).

Um... err... starting where?

@ June 25, 2014 8:03 PM in need electrical help

And what kind of boilers?  Steam?  Hot water?  What controls?

Honestly, if you are not reasonably current (sorry) on electrical work, it might be better to get a licensed electrician in to do the wiring, at least to the point of getting power, properly wired, switched and with proper circuit protection (and, if code requires, or you are so inclined, fire protection), to the boilers.

With two boilers the controls can get a little complicated, depending on exactly what you want them to do when.  Nothing impossible, but it isn't always obvious how to wire them.

As has been said in the other thread...

@ June 24, 2014 11:25 AM in New Geo System vs. Old Steam System System

(by the way -- thank you  for splitting the threads!) -- get Dave on this.  Usually in a steam system the only things that leak -- and they do leak, sometimes -- are wet returns.  Steam pipes themselves almost never leak, nor do dry returns (note:  I said "almost never").  Having pinhole leaks which blow steam suggests very strongly that you may have some failed traps, allowing steam into the returns -- and you may be running the pressure much too high.

Dave can evaluate both of these problems very quickly (and he really is one of the real top end experts), and neither should be particularly difficult or expensive to fix.

I like the idea of ice storage for the air conditioning.

Two comments...

@ June 23, 2014 9:06 PM in Need help rating these radiators.

First, as several folks have said, save yourself and your church a whole pile of money and get Dave over to refurbish the steam system for your heating needs.  Then add just enough air conditioning capacity to keep folks happy in the summertime.

Second, though, if your congregation is bent on appearing greeny (they won't be; refurbishing the steam system is actually a lot greener) and ripping out the whole existing system and getting the geothermal, you need to have someone -- might be one of the contractors, but better would be a well-qualified HVAC engineer to determine the actual required heating and cooling loads, including allowances for capacity for rapid recovery for services.  Granted, the existing system may give you a sort of a ball park figure, but that's not adequate for what you need at this point.

That's a house trap

@ June 23, 2014 8:54 PM in Trap on 4" sewer main in basement

and they weren't that uncommon at one time (the place I care for has two of them on the main building).  They are or were required by code in some jurisdictions.

The whole idea behind the thing is to prevent sewer gasses from entering the house plumbing.  They really aren't needed (unless your code says they are!) if all the rest of the traps in the house are properly vented, and if there are any floor drains or such like (including seldom used bathrooms!)  that arrangements are available to keep them wet.  On the other hand, they won't hurt anything... until they clog up.

They should be vented, however, just like any other trap.  If they are outside, there would be a vent also outside.  If they are inside, they may be vented through the rest of the plumbing (although that means that they are running traps which aren't really that great to have), but I have seen some vented with a short vent going to a grille in the foundation...

A few more thoughts...

@ June 16, 2014 3:19 PM in Calculate btus for OIl and Gas steam

First off, the size of the steam boiler required is determined by the installed radiation, not -- repeat, NOT -- by the heat loss of the structure.

Now if you change the amount of radiation, basing it on a conservative estimate of the heat loss in each room, then you can add up the installed radiation area (termed EDR) and determine the boiler size based on that.

On the other hand, if you keep the installed radiation -- which I would recommend, unless you are doing a pretty drastic remodel -- just add up the EDR of the existing radiation, and there is your boiler size.

Really simple.

But to repeat: the boiler size for steam has nothing whatsoever to do with the heat loss of the house!  The installed radiation may -- you can size that to heat loss -- but the boiler must be sized to the installed radiation.

It doesn't matter whether the fuel is oil or gas.  A BTU is a BTU, and an EDR rating is an EDR rating.  Which fuel you use is a matter of preference and cost and availability.

Now converting to hot water... we generally do not recommend doing so; there are just too many ways to get into varying amounts of trouble ranging from relatively mild pains in the pocketbook to truly catastrophic.  There is no good reason to do so; a good steam system, properly adjusted, will be within a few percentage points of an equally well adjusted high efficiency hydronic system, and it is unlikely -- at best -- if you would ever recover the additional cost (which could be very large indeed) in fuel savings..

However, if you were determined to do so, a BTU is still a BTU.  However, your installed radiation will not deliver the same BTUs on hot water as it will on steam.  On steam, the figure is 240 BTU/hr/square foot EDR rating.  On a high efficiency hot water system (trying to condense to get the efficiency), the figure will be about half that -- say 130 to 140 BTU/hr/square foot EDR rating.  Therefore you will need to evaluate the ability of your installed radiation to meet the heat load of the structure; then you could size the BTU rating of the boiler to suit.

For budgeting for the conversion, you would need to have the existing system evaluated pretty carefully, but for starters, assuming that the existing radiation is usable and doesn't leak at the higher pressures, you will need pretty much all new piping.

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!
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