Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Sucky Mod Con Efficiency.... (ME)

JohnNY
JohnNY Member Posts: 3,287
in THE MAIN WALL
How's it going with that D90?
Have you used the video mode yet? That seems to be the most significant difference between it and the D80, which is what I'm shooting with.





<A HREF="http://www.heatinghelp.com/getListed.cfm?id=290&Step=30">To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"</A>
Contact John "JohnNY" Cataneo, NYC Master Plumber, Lic 1784
Consulting & Troubleshooting
Heating in NYC or NJ.
Classes
«1

Comments

  • [Deleted User]
    [Deleted User] Posts: 0
    The need for service...

    All,

    As you might know, we have been exposed to recent weather conditions that were "design" and significantly below. Other than the occasional "cold call", I LOVE this weather. It gives me a chance to see how the systems we are designing are working under real time design conditions.

    Also, as many of you know, I have a Gionnini based mod con in my own home (final brand name really does not matter) and I have intentionaly NOT performed annual services to it to see what the net effect would be. I have yet to look under the hood, but I have enough flow meters and temperature sensors on it to know that at present, it's thermal efficiency is sitting at 61%. That SUCKS.

    The product is still working amazingly well as it pertains to modulation, etc. THe only difference being that I am sending more heat up the plastic vent pipe than in to the water. I am sure it's the crustaceans growing on the heat exchanger that are affecting the transfer rate/ability. I intend to pull it down, maybe this weekend to do a thorough examination (new D-90 digital camera) and cleaning and will re-document the increase in thermal efficiency.

    The lesson here, is to make sure that you re-inforce in the consumer the need for annual (every 2 years max depending upon the degree day exposure) combustion chamber cleaning and tune up service. Tell them to budget for it ($#00.00?) and put them into your calender so YOU don't forget to do the service. If you leave it up to them, they will forget, and their appliances will end up being 60% efficient like mine. Still able to deliver excellent comfort, just not efficiently.

    More to come.

    ME
  • Perry_6
    Perry_6 Member Posts: 1
    What fuel are you using....

    It would help is we knew which fuel you are using:

    Natural gas, LP, etc.

    I'm looking forward to the pictures too...

    Perry
  • [Deleted User]
    [Deleted User] Posts: 0
    Natural gas (NM)

    ME
  • Doug_7
    Doug_7 Member Posts: 250
    Double check - Flue temp ?

    Really good points on the need for boiler service to maintain efficiency. I look forward to the results. (Before and after service)

    But suggest you double check the flows and temperatures that go into the 61% efficiency calculation.

    Flue gas temperature correlates really well with boiler efficiency. If 39% of the heat was really going up the flue, the flue temperature would have to be much higher than any plastic flue pipe can handle.

    How does your flue temperature compare to your return water temperature ?

    Doug
  • Perry_5
    Perry_5 Member Posts: 141
    Not necessarily true...

    Flue gas temperature only correlates to efficiency if there is very little excess air.

    If you are running a lot of extra air through the boiler the flue gas temperature will drop accordingly.

    One thing to check though - is the accuracy of the temperature indicators - as they can drift (it is easy to set up an ice/water bucket at 32 F (let it sit a while to stabilize), and boiling at 212 F for reality checks on temperature indicators). Also flow should have stayed the same over the years as well - if not, that would indicate a flow meter problem.

    Perry
  • Brad White_203
    Brad White_203 Member Posts: 506
    Although at ME's altitude

    that 212 F. arrangement needs a bit o'adjustment.

    :)
  • Paul Rohrs_7
    Paul Rohrs_7 Member Posts: 173
    Fascinating thread Mark

    I would like to know a couple of things Mark.

    When was the unit last serviced?

    How did you measure Thermal Efficiency?

    Did you measure Combustion Efficiency? What was it?

    Paul
  • Doug_7
    Doug_7 Member Posts: 250
    Excess Air

    Yes - Efficiency correlates to flue gas temperature and excess air. Chart attached. You all know that.

    But - to get a 61% efficiency, even at 100% excess air, will still generate a very high flue temperature.

    I agree - check the temperatures and flows.

    Doug
  • Unknown
    Unknown
    Mark do you

    feel that your altitiude has any affect on operation?

    Also I can attest to failure to clean these condensing units can present problems. I have had five that had gone 4 years and they had a lot of problems and need to repair and replace combustion chamber material.

    I have had several others with 18 months of heavy service being used to supply hot water to an exercise gym. Those were a disaster when taken apart and cleaned with all kinds of white heavy corrosion all over the stainless steel tubing. It was very difficult to remove an clean.
  • Jed_2
    Jed_2 Member Posts: 781
    Question: Tim

    How do you think the rAy 200i would have presented under the same circumstances?

    Jed
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    Answers for Paul...

    Paul, It has NEVER been serviced, by intent. It has been in continuous operation for nearly 5 years.

    I have a flow meter on the hydronic side, a dedicated laboratory grade gas meter on the fire side, and the internal temperature sensors (confirmed accurate) on the unit itself.

    I clocked the meter under steady state conditions (extremely stable delta T).

    I clocked the gas consumption 3 times and got the same reading +/- 1%, under the same conditions.

    Output divided byInput = thermal efficiency.

    I have not, and probably will not check the fire side for CO, O2, Co2 etcetera. I see no real value to it other than making certain the unit is in compliance with the manufactures spec's. In retrospect, maybe I will swing by the shop and grab an analyzer, just to show the difference in theoretical versus actual efficiency.

    To the others watching this thread and commenting on excess air, this is true thermal efficiency, not theoretical combustion efficiency.

    Thanks for asking.

    ME

    There was an error rendering this rich post.

  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    Tim...

    I don't believe altitude has anything to do with it. I clocked the appliance when it was brand new, and it was up around 95% THERMAL efficiency.

    AT our altitude, with the less dense air, these negative pressure gas vavles help compensate. We use a deration factor for altitude that is 1/2 what an atmospheric appliance would have (2%/1000 feet ASL vs 4%/thou).

    I have tried forcing it to a sea level burn, and the CO got too high. ALso, I think you are aware of this, but our gas is not as hot as manufacturers think. Our local utility dilutes it with air so it is automatically derated for people dragging appliances up here from sea level.

    I am currently up at my high altitude testing laboratory (Hydronicahhh) in Heeney Colorado. (8,000' above sea level) but am using radiant windows to heat my little cabin, which don't require ANY deration :-)

    ME

    There was an error rendering this rich post.

  • Unknown
    Unknown
    Jed, I think it is too early

    to know how the condensing cast iron systems will hold up, time will tell.

    I do feel that the post purge circulator they have will eliminate high temperatures left over in the combustion chamber after shut down which may help keep clean.
  • Perry_5
    Perry_5 Member Posts: 141
    Mark

    I always assumed you were talking about actual thermal efficiency.

    Just want to check one thing. I presume you have asked the gas company for a readout on the BTU value per CF of gas. They actually test that - usually once a day - and can provide you some very accurate numbers on it. It rarely changes more than a couple of a percent though. But, they should be able to find the records on what it was when you installed the boiler as well (at least a monthly or weekly average).

    Perry
  • Unknown
    Unknown
    Mark I have been meaning to

    ask you to send me some info on those windows.My son owns a construction company here in New England and he is interested in them.

    One of my theorys on some of the junk that is showing up inside these condensing units is high residual temperatures left on shut down causing reaction with left over combustion aldehydes, alcohols etc.
  • Unknown
    Unknown
    Perry the average

    utility send out BTU content per cubic foot for a month is on most gas bills. You are correct it does not vary much unless they mix LNG and then you have to watch it as the LNG sometime has a higher BTU content. This is related to what is called the Wobbe Index.
  • TimS
    TimS Member Posts: 82
    output/input=mpg

    Forgive me i'm young and ignorant very interested mostly cornfused. It sounds like your idling in park I dont understand how you get efficeincy from that???

    I have different/same boiler in my house I clean, service, tune, check, tweek, upgrade, often, it keeps mama happy. Gas costs $$ per month, so I run constant flow turn temps down lower, shut off supply to family&kicthen area and dress warmer, hope fuel cost less $$ next month then mama complains oops I gone too far she is cold even running out of hot water in the shower so turn temp up to compromise oh yeah I am in control here but no where else.

    Now I have seen many a boiler that never been serviced some not too bad, some I can bring back to life, then others... oh I hate being the one to tell the family they have a dead boiler it happens , its much better to service often.

    Put heating in perspective. Are you comfortable or very comfortably warm at an affordable cost? How about your heat loss does that come in to the equation of efficeincy?

    I ramlbed some just ignore me I'll sit back and watch.I wonder if along with those crustaceans there is scale and maybe your HX has tiny pinhole disease causing the crustaceans?
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    Valid questions....

    Each and every one.

    It's good to be young and ignorant. What is more important is that you learn something new every day. My dad used to say, "If you don't learn something new every day, you were either A) Gone Fishing, or B) Not paying attention. If you WERE A) out fishing, and you didn't learn something new, you B) weren't paying attention. Pay attention.

    I like different same boilers, you've ALWAYS got at least half the tools you need to work on it. Clean is good. Efficient is good, I can afford the gas cost. They're going down. SHould I ignore it and see if it goes away (the inefficiency) I could stall it until I can't afford it.

    NEVER let your woman run out of hot water... And in the off chance that you do, buy her dinner t make up for it and keep picking up the toilet lid for her. She loves that. :-)

    I'VE SEEN A lot of boilers too, mostly metal (EXCEPT this ONE, Carbon composite jacket) mostly ugly. I've slept with a few, but nothing happened.

    I've put heating into perspective. I blended it in to the human comfort profile I stole form Robert Bean (www.healthyheating.com) and I call the end product comfort. My definition of comfort is not being aware of your surroundings. You're not hot, and your not cold, and you don't hear anything in the back ground. You're simply comfortable...

    I hate being the bearer of bad tidings too, bt that's what they pay me to do. ANd when I'm done delivering comfort, they forget about me. The same way I forget about my doctor who relieved me of pain... But I always try and remember to thank my doctor, every time I see them, which seem more often then not. Me, I'd be glad if I see them when little Billy is graduating from high school. But truth is, they need to see me every year...

    Heat loss? W e don't need no stinkin' heat loss! These things modulate around the real time load!

    Like my friend Dave Yates sez, "Door size, tag size, What's the difference?" or something like that :-)


    Me, ramble, NO WAY ;-)

    Are you paying attention??? You're here. I suspect you are...

    Welcome.

    ME

    There was an error rendering this rich post.

  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    Web site information...

    www.rgiglass.com

    I personally think the accumulation of gunk is directly proportional to the operating temperature. The higher the temps, the harder the clean. Baked on as opposed to washed away.

    Post purge on my Knight boilers is field adjustable. With a 30 second purge, my flue gas temps match my fluid outlet temps. Drops like a rock once the burner shuts down.

    AM going to capture and save all clinkers from the cleaning process so I can send it back to the manufacturer for evaluation.

    Thanks for the input.

    ME

    There was an error rendering this rich post.

  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    Hiccup (NM)

    Scuse me...

    ME

    There was an error rendering this rich post.

  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    Caloric content confirmed...

    I have an old friend in the gas lab...

    ME

    There was an error rendering this rich post.

  • TimS
    TimS Member Posts: 82
    AH Learned some , I better treat my BRIDE to dinner! then some.

    OH THANKYOU for the WELCOME Mark HeatingHelp It helps me wind down at night/wind up in da morn. MY hobby is my job (too busy to go fish ) I'm pathetic. Mark your entertaining and hilarious....

    EDIT: mama should be "BRIDE"

    Customers they want "efficeint" I dont sell efficeincy. Too many variables with existing conditions out of my control. I just do service, I try to sell comfort and reliability efficeincy is a side effect or bonus you hope, depends on the entire system, home, installation, emitters, its bound by something. I see you are focused on 1 factor the boiler.

    61% sucks NO WAY! (pessimist)cheer up! What is your base line? How do you compare that ? What was it new 62.76354%? edit: duh Im slow I see you say 95% recorded new.(pay attention you say! OK I Will DO and learn thank you mark I am humbled)This 61% may be good MPG you should be celebrating wahoo!!

    Cant tell you what my efficeincy is but I will say less than comfortable bit chilly (by choice) bought my bride two nice hooded sweaters and camo light coat for early Christmas gift so she be warm/comfortable HOT in camo. My system is handicapped (suspended staple up, unfinished basement, no insulation under basement slab, a/c supply in ceiling condensation freezes/thaws rains have to turn fan only on to keep the ducts dry in winter must be big heat loss YUP = poor plumbers radiant. IT WORKS. No one to blame but myself I can live with that. IF I could check what my mod/con efficeincy is: its likely singing near the same tune as yurs sucky nah, WAHOO this is normal.
  • Dave Yates (GrandPAH)_2
    Dave Yates (GrandPAH)_2 Member Posts: 377
    Secrets - giving away the store!

    ME,

    Been following this thread with great interest! My own modcon looks like a bowl of spaghetti exploded right now: wires sticking out with aligator clips attached as if some depraved surgeon was wielding a scalpel(G). Been logging watts consumed throughout my mechanical system in prep for the energy diet being staged. Have let my modcon go too - third year without a cleaning.

    Doorway & curb sizing methods! Now everyone will know how I handle heat loss/gain calcs(G). Came across an even better method this past week, but it's just for GSHP systems - size by the size of the existing ductwork. No need for Manwel Jay.

    Keep up the great diagnostic work. Always a pleasure to see what Doc ME is up to in his lab!
  • TimS
    TimS Member Posts: 82
    apologies

    Sorrry I was B not paying attention, very disrespectfull

  • GW
    GW Member Posts: 4,817
    me

    I missed something, you mentioned you're not checking gpm? then how are you checking thermal eff?

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    gary@wilsonph.com
  • Plumdog_2
    Plumdog_2 Member Posts: 873
    Excel gas

    Is it still about 880 btu/cu. ft? And I hear over the hill in Vail it is 1050 like normal?
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    829 to 831

    That western slope stuff is HOT, and if you're not prepared for it, it will create a lot of carbon monoxide. Gotta down size the orifi on that gas.

    ME

    There was an error rendering this rich post.

  • J.C.A._3
    J.C.A._3 Member Posts: 2,980
    Thanks MOM and Dad!

    They have taught me to live at "sea level"...and I've been there ever since.

    Where I used to live...you could tell when the gas company was being taxed for use, by the smoke coming from the gas sections of town. They pumped up the pressure with air,,,and the chimney's reflected it....in copious amounts.

    I'm watching this thread and anxiously awaiting the results from Mark. The teacher will lead the flock...Chris
  • bob_46
    bob_46 Member Posts: 813
    O.K Mark

    I'll bite where is Heeney CO....bob

    There was an error rendering this rich post.

  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    North of Silverthorne bob...

    Green Mountain Reservoir.

    Half way between Silverthorne and Kremmling on CO 9.

    I'v been going up there for 50 years :-)

    There was an error rendering this rich post.

  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    John...

    Just breaking it in. I will be using it to document radiant window testing and installation methodology.

    ME

    There was an error rendering this rich post.

  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    Tear down temporarily delayed....

    Confucious say best time to fix leaking roof is when sun is shining...

    He also said best time to service boiler is NOT during design conditions, like we're headed for.

    Next week.

    ME

    There was an error rendering this rich post.

  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    Gary...

    see My "Answers to Paul" further down. I am monitoring water and gas flow.

    ME

    There was an error rendering this rich post.

  • Perry_5
    Perry_5 Member Posts: 141
    What no snow...

    Gee I would have thought that it would be a winter wonderland this time of year. Instead only the mountain caps are snow-covered.

    I knew parts of Colorado were warm.... but not this warm (or perhaps global warming has hit out there harder than here).

    Perry
  • Perry_5
    Perry_5 Member Posts: 141
    But, ...

    The roof doesn't leak when the sun is shinning. No need to fix it then.

    How do you know if the boiler works when you are done servicing it if it's not going to run for weeks or months?


    Figured I should ask... ;)

    Perry
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    Sorry Perry...

    THat view was from a couple of summers ago.

    There is PLENTY of snow up there right now. So much in fact that I am looking at snowblowers.

    I have 18" on flat ground and drifts to 3 feet in areas.

    There was an error rendering this rich post.

  • GW
    GW Member Posts: 4,817
    OK, what kind?

    I was looking at doing some metering at my plcae too, I have a Vito 200 and a flaming blue beast stiing on the foor.

    What do you think about Hedland HA series ?





    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    gary@wilsonph.com
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,858
    Blue WHite

    http://www.bluwhite.com/

    Yours looks better, but probably costs more :-)

    ME

    There was an error rendering this rich post.

  • Doug_7
    Doug_7 Member Posts: 250
    Flue temperature

    Mark – As you know a fouled boiler heat exchanger will cause a higher flue temperature and lower fuel-to-water boiler efficiency. Flue temperature is important because it shows the energy that did not transfer from the fuel into the water.

    Overall boiler efficiency using the Input-Output method depends on the accuracy of the measurements of output - water flow and temperature, and input - fuel flow and energy content. I have used this method in industry and it depends on accurate measurements.

    Overall boiler efficiency using the Heat Balance method, which subtracts the flue and jacket heat losses from 100%, should agree closely with the Input-Output method. The heat always goes somewhere.

    Comparing the efficiency of a boiler that has run 5 years without cleaning or tuning, to the same boiler after cleaning and tuning, would be very valuable information. Flue temperature is an important part of the comparison.

    It is -23 here right now and going to -40 tonight. My Modcon is already flat out.

    Doug
  • Perry_5
    Perry_5 Member Posts: 141
    Much better...

    I am not sure how much snow we have if it were flat... Perhaps 14" (and a lot more on its way). I understand the 3 Ft drifts.... Same here (and I suspect higher in places - but I'm not going anywhere today).

    I'm glad that you are enjoying looking at snowblowers. Great dream they are - aren't they.

    Around here almost everyone has one - and if you don't have one you have a deal with the neighbor for major snows (or just clearing the drifting snow on windy days).

    Perry

This discussion has been closed.

Categories