Oil Tanks in Your Home

  For a technician or auditor that works outside of the Oil Heating Industry, seeing a tank leaking in a basement can send you into a moment of shock.  Then of course, the dreaded conversation with the Homeowner will cast a cloud.  The key is to have a plan, and know what to do.  The smallest amount of knowledge in this subject could make you the hero.  Simply stating, "Call your Oil Company!" can leave them feeling helpless.  Of course, that oil delivery company must know about a leaking anything, before chance of another delivery.  They likely have a magnetic patch kit that can be used to slow a leak while a permanent fix can be planned.

  The majority of oil tank leaks are caused by corrosion from water and sludge that has sat in the bottom of the tank for years.  Massachusetts Department of Environmental Protection (DEP) recommends homeowners have their oil tanks cleaned out at least every 10 years.  I firmly believe this is because regular maintenance is not always performed, so a qualified technician may not be able to identify a compromised tank.  Based on the picture I took, you can see that soil cleanup will be needed, but possibly groundwater as well.  This type of cleanup, based on MA DEP, averages $90K!  If this leak was identified quickly, and the sump pump does not turn on, soil cleanups can be less than $20K.  This is a significant difference, particularly for a homeowner and company's insurance premium come next year!

  Even with the high price of oil, averaging about $3.70 per gallon in Central MA, it appears oil heating in residential applications will be around for quite some time.  Thousands of homes are converted to alternative fuels every year, including but not limited to Natural and Propane Gas, Heat-Pumps and even electric baseboard.  All are viewed as more efficient and "cleaner" options.  With the many financing and fuel switching programs available, maybe a leaking oil tank is the time to call it quits with your long time oil provider?  Believe me, most oil companies thinking about the future of their business are expanding into alternative fuel options themselves! 

Clocking a Gas Meter

  After writing last week's post: "High CO Reading, Now What?" it occurred to me that not as many people out there: technicians, raters, or auditors; are up to speed on the age old firing rate calculation.  I hope this simple procedure is easily understood as you may find it useful if you are working with negative pressure gas valves, with Energy Star Homes, or just simply forgot your manometer at the shop.  I know most inspectors and raters avoid attaching a manometer to measure gas pressure, particularly since some states even require a license to service gas appliances.  By clocking the gas meter, one can tell if the British Thermal Units (Btu's) being consumed matches the input of the furnace, boiler, or even a water heater.

1. Turn off all Gas Appliances in the home.
2. Turn on the appliance being tested, to the highest firing rate (be careful of two-stage furnaces and variable capacity boilers, etc.)
3. Once at steady-state, use a stopwatch (last check there are about 219 Apps for that) to time how long it takes the smallest unit of measure (typically the 1/2 Cubic Foot) dial to make a full revolution on the gas meter.
4. Cubic Feet per Hour (CFH) = (3600 x Dial Sze) / Time (seconds)
5. CFH x 1000 Btu's = Input Btu/hr
6. Remember to relight any standing pilots that are burning up to $20/year!

  Based on the ACCA Quality Installation Specification, the basis for Energy Star Homes V3 Checklist, the calculated input btu/hr must be within 5% of the data plate.  If a technician properly adjusted the manifold gas pressure and adjusted the airflow to ensure the temperature rise is within Manufacturer Specification, at worst the input will be within a couple of percent of the data plate.

A couple of tips if this is new for you:

• When turning appliances off, I mean off!  A couple of standing pilots can throw off your calculations when you have a 40K btu/hr furnace.
• Know how to override any outdoor reset control on a condensing boiler.  The starting and stopping of these burners are the least efficient operation and will consume high CFH if short cycling, never mind the inflated Carbon Monoxide (CO) and Carbon Dioxide (CO2).
• For a more accurate calculation, replace the 1,000 Btu in the formula with the actual amount of Btu's per Cubic Foot.  This can be obtained by contacting your gas supplier.  Otherwise, it would be very tough to account for altitude.  For instance, I heard Denver operates about 860 Btu's per cubic foot or so.
• Also, I would recommend you clock (3) revolutions of the meter, then divide the time by three for an average reading in seconds.
• When working with propane, it helps to temporarily pipe in a meter to accurately clock as most tanks only have regulators.  Also, propane has approximately 2,500 Btu's per cubic foot.

  Has anyone ran across a digital gas meter yet?  I have not had the privilege of clocking one of these and would love to hear how you are doing so!

High CO Reading, Now What?

      Things used to be so easy when working in this business back in the day.  When carrying tools for some old timers, I remember some replacing an air filter and kicking the furnace while saying "Yup, still here!"  Maintenance these days, for great reason, has taken a more efficient operation mentality, mainly because energy prices have started to affect our wallets.  These days, 68% steady state efficiency oil boilers and gas furnaces with high carbon monoxide readings mean something.  But, does it necessarily mean we must replace the furnace, boiler, hot water heater, etc.?

     I heard a situation a couple weeks ago where a representative of a local gas company, whether or not he was a subcontractor I cannot be sure, completed some maintenance on a gas boiler that he ended up shutting down due to a high CO reading.  Most building analysts know that 26-100 ppm CO (in the flue, at steady state) means repair is necessary (see Combustion Safety Test Procedure, BPI.org), and to call a heating professional.  So why did this tech shut down and tag this boiler for replacement?  Was it actually a sales tactic?  

     High Carbon monoxide readings tend to point to what I like to call "unbalanced combustion".  You see, it could be due to lack of combustion air, too much gas, or too much excess air (not my blog, please keep clicking!). No matter how you slice it, the combustion process is out of balance.  I have seen high CO readings for draft inducers failing, secondary heat exchanger condensate drains clogging, improper manifold gas pressure, incorrectly adjusted draft dampers, you get the idea!  None of these reasons mean the equipment has to be replaced, but the recommendation could be made. 

  The boiler I started talking about earlier had a manifold gas pressure twice the recommended value.  There was too much combustion air due to a lack of understanding and/or measurement.  Since he took the readings, I doubt it was the latter.  Looking at the flame on a 90%+ AFUE appliance will never be a justified reason to crank up the manifold gas pressure.  If you cannot measure with a combustion analyzer, or even a manometer, at least clock the gas meter before you start creating high CO2 and CO outputs.  You are the professional and the homeowner is paying you for the expertise.  Please, don't recommend replacing a boiler your company may have installed just a a couple years ago!