How do YOU test a 3.5 mil boiler.....

Mark Eatherton

Was approached by my good friends who are the Lochinvar Boiler reps here in Denver to assist the factory in testing a 3.5 mil boiler up at the school. THe college was OK with it, however, there was a slight eentsy teensy problem. The boiler was too big to fit down the isles necessary to get it back to the lab.



Enter plan B. The rep agency has a great location, and a mechanical room with the requisite water, and drain and gas, however, the raw water flow ability based on the water main size was inadequate to be able to satisfy the needs of the boiler being tested. Where exactly would you put the btu's that this behemoth is going to generate?



I recommended the use of a portable cooling tower and generator to take care of getting rid of the heat.



Enter Aggreko Rentals...



I'd post pictures of the actual boiler they were testing, but was warned that it would not be a good idea to do so, so I didn't... But I can tell you that it has a 25:1 turn down, and is a down fired fire tube design, built by the fine folks at Lochinvar. The reps are aware of this product, and it should be out soon, after they get done fine tuning it for altitudinal applications and clearing the necessary approval agencies.



Here's the heat rejection equipment necessary...



Enjoy!



ME

Mark Eatherton

In as much as it is on their web site already...

I guess its safe to divulge the product name. It is the Crest.



http://www.lochinvar.com/_newsfiles/NewsFile_422688_Currents%20Spring%202010.pdf



Lochinvar = Innovation...



ME

hot_rod

while we are talking changes in

altitude and attitude, how does altitude effect mod cons or any induced draft appliances. What is the proper de-rate number to use? If it depends... what does it depend on?



Is that one of the questions asked in this testing?



Must be fun playing with big stuff now and then.



hr

Mark Eatherton

They wouldn't let me play with it ;-(

I wanted to fire that puppy up and see if we could get the cooling fans on that cooling tower to kick in...



Regards how much deration, I've heard everything from ZERO deration required, all the way up to 4% per thousand feet required.



Personally, without making any adjustments to the appliance, and clocking it with a gas meter, I've found the deration factor to be around 2% per 1000' ASL. That was one of the things the they were testing, was adjusting the fan speed (biggest freaking EBM Papst blower you've ever seen) based on atmospheric density at 5,280' to compensate for a lack of air density AND a lack of btu content of the gas here in Denver (830 btu/cu ft).



Their numbers were coming back amazing clean through the whole range of burner testing.



They are headed out Saturday for even higher elevational testing (Vail) before they wrap up and leave. They don't have to drag the 5th wheel cooling assembly along, because they have some place up there capable of providing the required flows (water and gas) and a means of getting rid of the exhaust. I warned them that some gas up in that valley comes from the western slope and that it was hotter than Denver gas.



ME

Jean-David Beyer

Derating a mod|con for altitude.

I do not know about most of them, but my Ultra-3 has a setting for high altitude (defiined as an altitude above 5500 feet). I do not know for sure what this does -- partly because I am at about 40 feet above sea level.



They seem to recommend a minimum firing rate of 20% for normal altitudes (1300 rpm for the blower) and 33% for high altitudes ( 1983 rpm).



For a medium firing rate, they suggest 47% at normal altitudes (2300 rpm) and 62% (3500 rpm) at high altitudes.



For high firing rate, they like 94% (5200 rpm) at normal altitudes and they do not say about high altitudes.



I do not know if these changes occur if high altitude is selected on the first setup screen, or whether it does something else.

SpeyFitter

25 to 1 turn down?

Hey Mark,

You're the second person I've heard from who has mentioned a 25 to 1 turn down on the Lochinvar Crest, the other was an inside sales rep at the local wholesaler.

If it is indeed a 25 to 1 turn down, why would they need multiple boiler models? Right now the Crest is slated as having a 1.5, 2.0, 2.5, 3.0 and 3.5 million BTUH models.

The 3.5 million BTUH model with a 25 to 1 turn down would have a 140,000 BTUH minimum firing rate. I don't know what more you could ask for from a commercial boiler than this?  The 1.5 million would have a 60,000 BTUH minimum firing rate. You could put this sucker in a big mansion with snow melt and let it modulate down to 60,000 BTUH to heat the house radiant, indirect, and pool and when that snow melt kicks on it won't even sweat either (well, it will, but inside the heat exchanger).

Mark Eatherton

From the horses mouth to my ears...

Scott, no bull. 25:1 .



Now, maybe we CAN handle the DHW loads in those drive thru body washes, the space heating loads AND the snow melting loads with one appliance with NO need for priority :-).



I will caution those of you reading this, that this is NOT a small boiler. It is small compared to a 3.5 mil atmospheric, but this thing still has a fairly hefty girth (Think double 3-0 X 6-8 mechanical room doors). I think they are targeting the large commercial market with this appliance tho.



Good looking appliance with the same front end as the Synch. VERY flexible controls with Mod Bus interface capabilities. These guys never cease to amaze me with what they are doing with the controls on these things. They are setting the bar really high for the competition to follow...



ME

Jean-David Beyer

What a deal! Just kidding.

I live on a short street with about 20 houses on it. Let us say each house has a heat loss of about 50,000 BTU/hour. Mine is a little less, all were built by the same contractor with essentially the same layout. A few have increased the size of the second floor (all were Cape Cods originally). Would be neat if we all got together and bought  the smallest one to heat the whole block! It would probably have enough to snow melt the driveways and sidewalks. I am not sure the gas company has the capacity on my street (about 2-inch plastic pipe, might be 3-inch, at about 15 psi, if I remember correctly). I do not know where we would put it.

Tim McElwain

JDB I know you like this stuff

so here is the scoop on "Flow of Gas Through Fixed Orifices"

The tables referred to are found in NFPA 54/ANSI Z223.1 The National Fuel Gas Code. Sorry the tables are too large to post here. Have fun, Oh by the way I actually think it is easier to get high BTU input equipment to 20 to 1 and 25 to 1 firing rates.

The other issue with this is what Mark mentioned and that is different BTU per cubic foot of gas in different areas.



Flow of Gas through Fixed Orifices



This annex is not a part of the requirements of this code but is included for informational purposes only.



F,1 Use of Orifice Tables

El.I To Check Burner Input Not Using a Meter. Gauge the size of the burner orifice and determine flow rate at sea level from Table F.1, Utility Gases (cubic feet per hour), or ,from Table F.2, LP-Gases (Btu per hour). When the spe-

cific gravity of the utility gas is other than 0.60, select the multiplier from Table F.3 for the specific gravity of the utility gas served, and apply to the flow rate as determined from Table F.1 When the altitude is above 2,000 ft (600 m), first select equivalent orifice size at sea level using Table FA, then determine flow rate from Table F.1 or Table F.2 as directed. Having determined flow rate (as adjusted for spe­cific gravity and/or altitude where necessary), check the burner input at sea level with the manufacturer's rated input.



F.l.2 To Select Correct Orifice Size for Rated Burner Input. The selection of a fixed orifice size for any rated burn­er input is affected by many variables, including orifice coef­ficient, and it is recommended that the appliance manufac­turer be consulted for that purpose. When the correct orifice size cannot be readily determined, the orifice flow rates, as stated in the tables in this annex, can be used to select a fixed orifice size with a flow rate to apprqximately equal the required rated burner input.



For gases of the specific gravity and pressure conditions stipulated at elevations under 2000 ft (610 m), Table F.1 (in cubic feet per hour) or Table F.2 (in Btu per hour) can be used directly.



 

Where the specific gravity of the gas is other than 0.60, select the multiplier from Table F.3 for the utility gas served . and divide the rated burner input by the selected factor to determine equivalent input at a specific gravity of 0.60; then select orifice size as directed above.





Where the appliance is located at an altitude of 2000 ft (610 m) or above, first use the manufacturer's rated input at sea level to select orifice size as directed, then use Table FA to select the equivalent orifice size for use at the higher altitude.