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SWEI

SWEI

Joined on November 26, 2011

Last Post on July 29, 2014

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residual boil

@ February 11, 2013 8:26 PM in vapor vacuum with reverse tankless coil?

I must be missing something here - couldn't you just continue firing the main burner?

I did get one answer

@ February 11, 2013 7:37 PM in Tankless WH as booster

From A.O. Smith (Takagi) but it's not quite as simple as I thought.  I've attached an example for the GTS310 (TK-4) below.

The application is for occasional booster heating of an existing SHW storage tank.  Since Takagi includes an "H" stamp on them, I can comfortably specify them (once I add proper controls and safeties.)

low line pressure

@ February 11, 2013 7:21 PM in The white Stuff

can be caused by demand increases nearer the source.  About two years ago, a coal-fired power plant in TX (in an area where historically they don't see icing conditions) had its turbine inlets ice up.  The utility fired up a couple of NG peaking plants typically used to meet summer heat demands which sucked down line pressures across the region.  Customers located ~300 feet or more above downtown lost their service.

277V single phase

@ February 11, 2013 7:11 PM in 277 Volt Circulator pump

only exists in a 480 Wye system, so there is 480/3ø in the building someplace.  It's hard to find 480/3ø motors smaller than half a horsepower so as Ironman pointed out, it really depends on the pump.

ECMs are typically limited to 250V supplies, which is unfortunate since they could quite easily be designed to run on 90-300V, making them applicable to pretty much any AC power system on the planet.

you have to look at the bill

@ February 11, 2013 7:03 PM in NG pricing, Henry Hub vs City Gate

which includes a number of other charges.  Seasonal price trends matter, but you need to look at those in the context of wholesale prices in order to even begin to understand them.

Thanks to ever-increasing demand from the transportation sector, liquid fuels currently command a significant premium per BTU over gaseous fuels.  Everything I read indicates this premium will continue and perhaps even increase.  If you have information to the contrary, please share it.

feet of baseboard

@ February 11, 2013 6:54 PM in Heat loss, what size boiler do I need?

70k of baseboard with a 55k loss would allow you to run lower water temps, which would be a good thing, particularly with a mod/con boiler.

NG cost equivalent

@ February 11, 2013 5:47 PM in Convert only the oil burner head to gas?

$2.30 oil comes out to $1.66 a therm -- yikes.

Out here we'd have to get oil at 78 cents per gallon to match the NG prices.

http://www.eia.gov/neic/experts/heatcalc.xls is worth a few minutes of your time before you make a decision.

hydro separators

@ February 11, 2013 5:36 PM in Eatherton "flux sponge"

Are wonderful.

I'd like to see more tank-type designs with additional ports - the buffer space can really help with smaller loads.

No offense taken

@ February 11, 2013 11:24 AM in Heat loss, what size boiler do I need?

and we also upgrade conventional boilers with ECM circs and ODR controls.  I have found that the the increased first cost of a mod/con usually goes away by the time a buffer tank, additional circulator, controls, piping, and labor are added to the cost of a conventional boiler.

If the oil boiler is in good shape, then a gas gun, buffer tank, and ODR may well be the best option.

trenchless replacement or relining

@ February 11, 2013 10:44 AM in Leaking steam lines in earth under concrete in living room

is another option, depending on layout and diameter.  Someone posted a link to a company that does epoxy relining of steam lines a few months back -- don't think we've seen a post-repair report yet.

Slab on grade construction is fine for garages and industrial space but raised floors make far nicer living.  One more reason I tend to prefer older houses.

nice work

@ February 11, 2013 10:12 AM in Eatherton "flux sponge"

Is that a Caleffi 548?

uninsulated returns

@ February 10, 2013 11:31 PM in Water preheat?

are often what keeps the basement habitable.  I'd proceed carefully.

Building heat loss

@ February 10, 2013 11:07 PM in Heat loss, what size boiler do I need?

plus system losses should equal boiler output at design conditions.  The efficiency of a mod/con boiler drops a bit with higher return water temperatures, so there is some interaction with system design here.

Assuming the heat loss is accurate, I'd probably look at a Triangle Tube PTS60 or a Lochinvar WHN055 for that heating load.

Proper indirect sizing depends on your use pattern and the boiler size.  Be sure to look closely at manufacturer's performance data.  Most indirects show performance with ~190F boiler supply, but you can increase efficiency with a larger indirect (by supplying lower temperature water from the boiler.)

so would it be possible

@ February 10, 2013 10:41 PM in Gas-Fired Steam without Electricity?

to setup a series valve arrangement (like we see on commercial gas trains) using two modern millivolt valves, with two pilot TCs separately heating?

I don't think I could put my name on it

@ February 10, 2013 10:38 PM in Why does this set up "work"?

without checking at least gas pressure and CO.

another validation of the original T87

@ February 10, 2013 10:03 PM in Zone Problems

So I have to wonder - is there some country where they still allow mercury switches in which Honeywell has a presence?

pressure-dependent circulator

@ February 9, 2013 4:22 PM in Bypass valve

would be a better answer.  How big is the system?

heating it further

@ February 9, 2013 4:11 PM in Water preheat?

implies higher pressure.

So 1 PSI (215.6F) steam should be able to be produced with a flue temp somewhere around 220-225F.  Might not prove to be cost-effective, of course.

Mega-Steam burns oil

@ February 9, 2013 12:14 PM in Water preheat?

at least officially.  Enreynolds reported 344F with NG on his.

http://www.na-stordy.com/seminarCD/pdfs/hbs39.pdf covers the non-condensing territory.

Given the almost nonexistent approach mod/cons demonstrate, it should be possible to create 240F steam with a 245F flue temp.

flue temperatures

@ February 9, 2013 11:59 AM in Water preheat?

Should be quite a bit lower than that on a properly tuned three pass.

nice work

@ February 9, 2013 11:25 AM in garden hose for gas line

gas pressure

@ February 9, 2013 11:11 AM in Why does this set up "work"?

where was it on/off fire?
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