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Excessive gas Use ?!

jim_180 Member Posts: 8
i Have a Munchinkin Contender mc120 wall hung. i have had it in  operation since November2010 and the average consumption is about 7 gallons of LPG per day. my home is 1900 sq ft living space with an additional 200 sq ft bonus room and garage. (the garage temp I keep at 40 degrees) I have a front wall facing northwest that is mostly glass windows and door with a vaulted celling with an open balcony over the family room. The home is on a 6' slab with 5/8 OD pex tubing in concrete with 5/16 hardwood floors. the 1/2 story above uses the same tubing mounted on Viega snap panels covered with the same hardwood. The unit was converted from natural gas to LPG. Combustion analyst shows o2 readings of 6.6 on high fire and 6.1 on low fire. co2 readings are 9.6 and 9.9 respectively.eff reading was 98.2. I run water temp at 130 degrees with a 30 degree differential. i have 7 zones coming from 3 different manifolds. Each manifold is supplied with a taco 007 ifc pump and the primary loop is using a taco 0014 ifc pump. I have checked for gas leaks and unless I have a configuration problem I am at a loss unless this is normal for this unit. i do not have a DWH attached to the boiler. Any suggestions would be appreciated. 


  • meplumber
    meplumber Member Posts: 678
    What did your heat loss for the structure come up to?

    You can expect 94,000 btu's per gallon of Propane.  So at 7 gal per day, that is 658,000 btu's per 24 hr period or 27,417 btu's per hour.

    Running some vague numbers, I have your available radiation output at somewhere around 50,000 - 60,000 btu's per hour. 

    Sounds pretty close to me. 

    What is the design temp in your area?  How cold has it been there lately?   Is the house making temp?  Is it comfortable?
  • jim_180
    jim_180 Member Posts: 8
    Excessive gas Use ?!

    Here is a summary of the heat los prepared by pex Supply. I have the full report available if you need it.

    Temperature here has been around 0 to 5 above at night and average around 15 degrees during the day.

    Most of the first floor zones are being satisfied. I have a upstairs bathroom on a northeast side that has gone to 60 degrees when we have a north east wind. The bonus room over the garage also has trouble reaching temp, I spaced the pex 12" apart I didn't think I would use this room as much as I am. I could put in some wall radiation to compensate for this. Overall temp is around 68 to 70 in most of the main living areas.

    Design Data Location: (User-Specified Location)

    Outdoor Temperature: F -10 °

    Wind Speed: 21 mph

    Total Area: 2,547 ft²

    Construction Quality: Average

    RFH Glycol Level: 100% Water

    Design Temp. Drop: 10 °F

    Radiant Tubing Volume: 47.3 gallons(US)

    Volume Water: 47.3 gallons(US)

    Volume Glycol: 0 gallons(US)

    Total-Components Load: 26,174 Btu/hr

    Total Infiltration Load: 21,117 Btu/hr

    Total Floor Downward Load: 12,760 Btu/hr

    Total-Radiant Load: 50,032 Btu/hr

    Total-Supplemental Load: 0 Btu/hr

    Total-Project Heat Loss: 62,792 Btu/hr

    I have yet to side the house. I have r21 in the walls and 1/4 inch foam sheething over the outside walls to help with the wind.


  • CMadatMe
    CMadatMe Member Posts: 3,086
    edited January 2011
    You Oversized the Boiler

    Yes you are using excessive gas. Your boiler is oversized. You are using a 120,000 btu boiler for a 60K load. You have twice the boiler you need. The Contender also does not utilize outdoor reset unless you purchased the optional Vision 1 Package. There is a way to minimize that load on the boiler though you need a combustion analyzer and reduce the rate of modulation if possible.

    How are you controlling the water temp for the radiant? Also the design temp drop at 10 is a little lite. Generally a 10 degree delta-t is great for concrete but for joist should be a 20 with no plates and a 15 with good extruded plates. What about water temps and loop lengths for the particular rooms. Can you provide that info?

    May I ask why you went throught an internet company to provide you with a heat loss and radiant design? I'm curious as to why you haven't gone to them with your problem since they designed it and provided the product to you.

    I just find it weird that someone goes to an internet company and I'm going to assume because you wanted to save a few bucks over the local contractor and then you come here to find a contractor to help you out FREE OF CHARGE..... 

    My suggestion is to call PEX Supply and have them come out and troubleshoot the job. Would be no different then your local contractor calling his supply house and doing the same if he couldn't solve your issue or needed another opinion. But that's why he charges more. He's there to help you when you need it.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Tim McElwain
    Tim McElwain Member Posts: 4,588
    It would probably be

    a good idea to get in touch with the tech services at Heat Transfer Products. The excessive BTU input versus your heat loss will present problems unless the factory can recommend a solution.
  • icesailor
    icesailor Member Posts: 7,265
    edited January 2011
    Loosing Heat/Gas


    You blew it on this one.

    Did you miss the fact that he has no siding on the house? Other than some foam boards? I don't care how much radiation he put in, the boiler can't over come the heat loss through infiltration and exfiltration. How much else is unfinished on this house?

    I once did a house for someone and learned a lot. I knew I had the correct radiation in the house. The house wouldn't get to 60 and it was 34 degrees outside. I had designed it for 0 F. The wind was gusting over 30 MPH. I pointed out that none of his knee walls were covered with sheetrock let alone insulated. That all his recessed ceiling lights in his cathedral ceiling  were sucking air from the room and to the outside. Through soffit vents and ridge vents.

    Be right back,,,,,
  • CMadatMe
    CMadatMe Member Posts: 3,086
    Boiler is Still Oversized

    I hear what you saying Ice but the boiler no matter is still oversized based on the heat loss.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • icesailor
    icesailor Member Posts: 7,265
    Excessive Gas Use

    I had to go. I came back and finished. I lost it. So,

    The boiler is ALWAYS too big until it hits design temperature. The guy is trying to heat an unfinished house. Or a house with poor construction and has very high heat loss through infiltration. The fact that some room/zones don't come up and others do are the tip off. If the boiler was smaller, it probably wouldn't get to temperature on high limit. I'd like to know what his return water temperatures are.

    I always understood LP/Propane to be 91,000 BTU's per gallon.

    I was once asked to DX a high gas use on a new house. Beautifully done, archetect designed. All boxes connected. Finished with rough sawn tongue and groove pine. The house would heat right up on a cold windless day. On a cool windy day,it wouldn't heat up and the boiler wouldn't shut off. LP Gas. An "Expert" came and declared that the boiler was too small or wrong. They changed the boiler to a different and bigger size. Same problem.

    I foind that the T&G pine boards were nailed to the studs and rafters with no poly vapor barrier or sheet rock. The wind and heat flowed through like an open window. There was enough installed baseboard to heat it at 150 design temp. and running it at 200 wouldn't heat the house. Just burned a lot of gas. Don't ever underestimate the effect of wind induced infiltration and exfiltration.
  • jim_180
    jim_180 Member Posts: 8
    Thanks anyway

    I had already called Pex supply with the problem. They said they had no one in the area to do trouble shooting. I called HTP where i had purchased the product they suggested Everson swan who i also called. they did not want to drive the hour and a half to come check it. The hvac guys in my area I've called say they don't have the knowledge to service this type boiler they are use to servicing fuel oil boilers.

     I am not looking for a free ride I just needed some help. Obviously your to ignorant or arrogant to know the difference, and I was wrong to try this site to get help.  oh but thanks any way! 
  • icesailor
    icesailor Member Posts: 7,265
    Ignorant and Arrogant:

    Jim. You get what you pay for. We give you free advice that is correct and you paid for advice and a designed system that isn't working. Don't blame us/me.

    I've spent over 40 years looking at things that someone screwed up. Or things that needed help. I have seen your problem more than once. I give you examples of what I have seen that seem to match your problem.

    Wherever you live, I don't think you have reached design day. The coldest day your system is expected to see. You said that some zones heated to inside design and some or one was 10 degrees off(60 degrees). If the boiler/burner was cycling on and off during one of these coldest times, the boiler is big enough. If it isn't doing the above, your boiler is too small and running constantly. It's not OUR fault you have the wrong boiler. It costs money to heat a structure.

    Good luck being a non-professional and getting someone to figure out your problem. With an attitude like yours, I wouldn't go near it. You know way, far more than I do. 36 years in the plumbing, heating and water well and pump business counts for nothing. But some person on a computer with a computer and a CAD program can tell you just what you want to read/hear. You shouldn't have asked us, you should have asked the person who designed it for you. If you had someone install it for labor, don't turn blue holding your breath.

    Good Luck.
  • Mike Kusiak_2
    Mike Kusiak_2 Member Posts: 604
    Unrealistic expectations?

    Is the fuel useage really excessive? As posted by someone earlier, propane useage is 7 gal/day or about 27K BTU/Hr with average temperatures between 0 and 15F. Heat loss calculated at 62K BTU/Hr at design temp of -10F. So actual BTU input is less the half design heat loss. Even if the boiler is oversized, how bad could efficiency be if the total heat input averages only 27K BTU/Hr?
  • CMadatMe
    CMadatMe Member Posts: 3,086
    As Ice Has Said

    It's not our fault. You basically got what you paid for. I travel the hrs Pex Supply won't for our customers. But again that's why hiring a contractor cost more. They have the support that is there when they need it. The few bucks you saved purchasing from PEX Supply is being eaten up and that's not our fault.

    The problem you are running into is that PEX Supply doesn't purchase from manufactures. They find a wholesaler that is willing to sell to them but the mfgs will not and don't service and trouble shoot for them not do they warranty the product purchased from them. Your on an island with no way off. I
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • icesailor
    icesailor Member Posts: 7,265

    I totally agree. And if the house was finished and tight, it would go down even more.
  • meplumber
    meplumber Member Posts: 678
    I caught that ice after my original post.

    I was just running vague numbers from what he gave us.  I also missed the size of the boiler in his original post.

    I ran into a similar thing a few years ago.  HO bought a boiler online.  Installed himself and then got mad at me because I couldn't "fix" it and make it run like a cadillac.

    He got what he paid for.
  • jim_180
    jim_180 Member Posts: 8
    thanks to all

    Thank you to everyone who has commented on this thread. You gave me some insight on what to do and how to proceed, not only with the boiler but understanding you are really here to give good advice. I made some remarks out of frustration That were nobodys fault but my own. Online busness can be used for research and info but can never replace the human interaction needed to slove problems. I had a excellent heating person, and also a very good friend. He was also a gattling gun enthusiest. He was killed in a car accident a few years ago and I think some of you might recall him he had recomended this site if I needed questions answered. Any way thanks to all and if I offended anyone I am truly sorry. I have learned from this experience.
  • Tim McElwain
    Tim McElwain Member Posts: 4,588
    We all need to be a little more

    civil when folks come here asking questions. These are trying times and money is tight so folks look for the easy way to get something done, I am certainly against people buying equipment from questionable sources. That being said we do not need to put them down because it hits a sore spot we have about that type of thing.
  • CMadatMe
    CMadatMe Member Posts: 3,086

    Tim I totally get what your saying. If someone purchases off the internet and gets themselves in trouble and cannot get any support then our best advice to them is to contact a local pro. The last thing you want to see is someone taking some advice but not apply it correctly and end up in more trouble.

    The best any of us can do is to provide insight as to what a problem may be and strongly stress that they need a pro. The shame of internet sites is they leave someone hanging such as this gentlemen and get away with it. It's a crime in my book. In this case they provided a heat loss and product but are not willing to support their customer. They are a multi million dollar company and can afford an overnight stay at the local Motel 8 and some gas money.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • meplumber
    meplumber Member Posts: 678
    Good point Tim.

    Like many of you, for me, sleep is a rare commodity this time of year.  The phone sometimes rings faster than we can drive.

    I have caught myself a couple of times recently about to fly off the handle in a situation that normally wouldn't even register with me.  Civility wouldn't hurt.
  • bklynfrank
    bklynfrank Member Posts: 15
    edited January 2011
    Beating a dead horse.

    I just read this thread and got kinda mad.

    Heating pro's get mad at homeowners that want to take food off their table with diy, lowest bidding, and internet shopping.

    Here is my story.

    I'm a landlord who gets mad at plumbers who pretend to be heating pros and have made mistakes on each of my 4 steam/2 Hotwater boilers.

    Now with Dan's books and reading the posts here every day, I get more angry at these installs.

    Each boiler is oversized. 

    Each one has venting issues that were there at install time.

    Each one has some kind of nearpiping issues.

    Each was installed by a different plumber and I don't hire randoms from the yellow book.

    I ripped out an old steam/oil one and put in twin hotwater boilers to get away from steam. I wont do that again.

    The latest steam install (2008) had 3 leaks @ nearpiping the first time it went to pressure.  The plumber already left. do you think he skimmed it?  Doubt it.

    Each job was a no bid.  They came, told me what they will do, when and how much.  I said it will work better, and save me fuel? Ofcourse they said. They were right about that, moved from oil to gas was my savings than from anything else. 

    As I read the posts, I see more and more problems that I have or had.

    At this point, I think I can screw up an install with the best of them.  Looking to buy 4" threader.

    I definately understand the pounding the pro's get from being undercut by plumbers and homeowners that only care about the cost.


    By the time I/we get to Heating Help, we are getting religion, and looking to fix the damn things ourselves.

    Now for my sorry clause.


    I'm sorry if I reflamed a closed topic

    I'm sorry I got people mad

    I'm sorry I picked a side


    Hopefully, I will never be sorry to participate.
  • CMadatMe
    CMadatMe Member Posts: 3,086
    Giving and Getting Advice

    I see and can here what BrklynFrank is talking about. Homeowners come here looking for us to fix their problem because by the time they find us there fed up and lost trust in their local trademans. Some brought in on themselves others did not.

    My only concern is that a homeowner takes advice and attempts to fix a problem themselves when the information we give is really in some cases vague or things to check. I love to educate and provide all help but I hope they use it to find the Pro in their market instead of the non Pro because he's less expensive.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • jim_180
    jim_180 Member Posts: 8
    bottom line

    I am a cook by trade, I have experience in computers and electronics. I love a challenge and being able to learn things i haven't done before. The bottom line now to me is that these types of mistakes are very costly an well better off leaving it to the people who are trained and have the knowledge to dothe job right the first time. It may seem costly at the get go, but believe me the end result is far less costly.

     As far as getting reputable help, we as homeowners have to do the homework, ask for references and referrals and give these guys a chance to do what they are trained to do.
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,253
    Jim what you get here is usually

    basic information to get you in the right direction. I travel up to 4 hours to trouble shoot and repair what others do not do right the first time. I get paid to fix systems where the repair sometimes is more than the original installation cost. When I am done it works as it should. In my state home owners can not legally buy heating equipment and maintain the manufacturers warranty. Why you may ask? The answer is not to protect the installation companies profits. It is to protect consumers from dangerous installations and to make sure the job is sized as it should be. This is great if the job is inspected by an honest and knowledgeable inspector. Sometimes jobs go in bad even with these safety nets in place.

    Get the outdoor reset up grade for your boiler and If you can install the upgraded control yourself that is fine. If you can not than come back and ask for some input. If it is beyond your comfort level than check above for a pro to do it. The guys who say they can not work on your boiler as they are not familiar did you a favor as they could have made things worse. Where is your area?

    Good luck with getting the rest of your home done.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
This discussion has been closed.