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Tractor_RV

Tractor_RV

Joined on March 26, 2013

Last Post on March 26, 2013

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Outdoor_Propane_NO-NO's & Axia 29E

@ March 26, 2013 3:07 PM in Combi Boiler Recommendation

Axia 29E specs are: Input Rating: 160,000 btu/hr.
I stumbled across this website BLOG looking for some Axia 29E parts, or knowledgeable techs.
I will attempt to provide sufficient answers and relevant resources to address all of the issues that I am reading about the Axia 29E.
I live near Saranac Lake, NY where it gets -40 degrees to -60 degrees many winters, even if only for a few days each year.
My nephew is a licensed HVAC tech, commercial and residential. The old part of my business has baseboard heat, and the 2000 year
addition has in-floor PEX in the cement with 8 zones. Three propane boilers, and a digital controller. My nephew and I put an Axia 29E
in my home in 2007, and now I need some igniter parts, and will be good to go again.
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My answers for many of the issues on this web page.
The current problem is that the low water cut-off valve gets stuck causing the unit to shut down -- at least that's what I'm inferring since a (more or less) gentle tap with a wrench results in the unit firing up again. Another recurring problem is that the safety relief valve gets stuck on open. Typically, I don't catch this right away, leading to a bit of a mess in the crawl space where the unit is installed. Also the circulator pump is seeping water at the joints. Perhaps this unit will last a long time, but we just don't trust it anymore. Paul Disclaimer: I know next to nothing about boilers, so take what I say with a grain of salt.
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Problems -01)
(HARD WATER & CORROSION PROBLEMS)
Low water cut-off valve stuck; safety release valve stuck open;
circulator pump seeping water; (all equal signs of hard water & corrosion).
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(COLD Outside where the Propane tank is.)
Propane bills are HUGE-out of sight!!! 500+ gallons/month and it won't raise temp over 62 degrees when outdoor temp goes below 20.
Cuts off constantly for no reason -
have to have one person man the unit to reset the boiler when it goes off while someone is showering.
Often wake up to cold house with boiler cycling endlessly as it tries to reignite.
Too cold at the tank = Low volume flow, or no flow = out of gas.
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Problems -02)
(COLD Outside where the Propane tank is.)
It won't raise temp over 62 degrees when outdoor temp goes below 20.
Boiler cycling endlessly as it tries to reignite.
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we bought a house in Santa Fe and it has a Cosmogas Axia unit that heats the floor (radiated floor heating) and supplies hot water for the kitchen/baths.
Our propane bills were outrageous ($700 per mo) in the winter (and it was a "warm" winter). The thing just quit with a red "low pressure" light and the manual is completely vague about what to do. The unit cycles on and off (when set to 140 degrees) every few minutes, working itself to death.
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Problems -03)
Axia unit that heats the floor (radiated floor heating).
The unit cycles on and off (when set to 140 degrees) every few minutes, working itself to death.
Our propane bills were outrageous ($700 per mo) in the winter (and it was a "warm" winter).
The Axia 29E recovers very quickly, and 140 degrees may be too much heat for the {PEX, I am presuming} to last very many years.
An HVAC engineer could design a crossover radiator and storage tank with its own circulator to keep the floor heat even.
The unit cycles on and off is called "Short cycling" caused by the furnace catching up to the "Load" very quickly and turning itself off.
This is a POOR Installation design; nothing to do with the Axia. You will have the same problem with every furnace, until the issue is fixed.
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Problems -04)
We live in the upper peninsula of michigan (COLD) and efficient it is not. (COLD Outside where the Propane tank is.)
My 4800 sq.ft home costs $800.00 a month to heat when it is running!
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ANY AREA OF THE U.S. that gets colder than Freezing more than a day or so; needs an underground Propane Tank Install.
(In my opinion) Reasons why. Look at the Axia 29E Input Specs: they call for 160,000 btu/hr of propane (FLOW).
Axia 29E specs are: Input Rating: 160,000 btu/hr.
Look at my Resources List of web pages; especially the (3) Propane Vaporization Rate Charts.
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A 500 Gallon tank has to be (20 degrees above 0) and over 10% Full - to supply 182,000 btu/hr.
A 1000 Gallon tank has to be (above 0 degrees) and over 10% Full - to supply 200,200 btu/hr.
My solution is to install (Underground Propane Tanks) of the appropriate size and cover them with 2-Inch
Blue Dow, or Pink Dow 2-ft -x- 8-ft underground foam. The ground temperature hovers around 50 to 55 degrees
below the Frost Line, and the dow foam keeps the frost from touching the tank.
Therefore I never have a propane fuel supply issue.
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ALL of the issues on this website page can be explained by a LACK of HVAC training and understanding.
The following resources are provided which will explain all of the above issues; plus supply line sizing;
manifold and regulator sizing. Instead of a 2 stage regulator, I prefer to place the tank farther from the home,
put a high pressure regulator at the tank; and a low pressure regulator on a house manifold for (EACH)
propane appliance. Plus, size the correct supply line to the home!
Best wishes.
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Resources: INFO
500-1000 Gallon Propane Tank Vaporization Rate Charts
http://www.hytopz.com/sales/products.asp?cid=1334
500 Gallon Tank - 41" x 8'8" overall, using percent in tank at various temperatures
Figures in B.T.U. on this chart are approximate as there will be many variations due to tank location,
wind velocity, humidity, altitude, type of demand or draw (such as periodic or continuous loads).
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REMEMBER, unless all gas-consuming appliances receive the required flow of gas at the correct pressure,
trouble can be expected and will NEVER be corrected until the required volume is delivered.
Therefore, selecting the CORRECT size storage tank is VERY IMPORTANT.
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Calculations are based upon continuous withdrawal, minimum liquid temperature at -20 degrees
with a tank pressure of 10.7 pounds in still air conditions in open area.
Propane 2,500 BTU per cubic feet - 91,000 BTU per gallon of liquid at 60 degrees F.
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Propane Vaporization Rate Information
http://www.nbmc.com/heaters/lpchart.html
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Boiler closed Loop (need for treatment)
http://www.facilitiesnet.com/energyefficiency/article/Boilers-Saving-Energy-Contributing-to-Green--7760#
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http://www.rhomarwater.com/products/residential-hydronic-radiant/
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DIY _ Cleaning & protecting (Older boiler systems)
http://www.doityourself.com/forum/boilers-home-heating-steam-hot-water-systems/477023-water-chemsitry-new-high-efficiency-boiler.html#b
http://www.sentinel-solutions.net/product/listing/central-heating/rapid-dose/
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Propane Technical Pocket Guide = Free Download
http://www.buildersshow.com/assets/images/showpage/PropaneTechnicalPocketGuidepdf.pdf
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