Christopher Morin's Blog (35)

On-Call for the Holidays?

   This seems to be one of the unluckiest weeks to draw in the on-call pool for a technician.  You see, over the Winter you have to respond to no-heat calls much faster than a residence without cooling on Memorial or Independence Day.  I remember visiting homes many Festivus evenings and getting the old clunker of a boiler running, without the swears from "A Christmas Story".  But, even over the last fifteen years, being on-call has changed.  If you were not able to  barter your way out of…

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Added by Christopher Morin on December 22, 2012 at 10:07am — 1 Comment

A Successful Technician

I am sure I am not the first to write about this, but it doesn't change expectations of homeowners or trade employers.  Why is it that millionaire ball players can be successful batting .300?  A pitcher can have thirty starts, win 20 games and could be named for the Cy Young?  Or that a successful quarterback can throw 20 touchdowns and 10 interceptions?  The reason: they are much better than their peers.

     Imagine, as an HVAC Tech, you got the diagnosis correct  one-third of the…

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Added by Christopher Morin on December 4, 2012 at 7:00pm — No Comments

Return Air Locations

     When using ACCA's Manual T for register selection, there are several basic rules that are followed regarding location. Most guidelines revolve around room air circulation and stagnant air, as well as the equipment application (heating only, cooling only, or combination). Application is the largest determining factor when it comes to return air locations.

      For heating only applications, a low return duct is ideal to bring back the coldest air otherwise stagnant in the room.…

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Added by Christopher Morin on November 17, 2012 at 10:39am — 3 Comments

Building Code: ACCA Manual S

     A seldom practiced design procedure, equipment selection, has been part of the International Residential Code for many years, and local MA/RI code at least since 2010.  This critical step is the second part of residential system design, following a Manual J load calculation and prior to the Manual D duct design.  I think confusion around the dated manual has contributed to lack of use and enforcement.  Whether you are installing an air-conditioner, heat pump, furnace, or boiler, there…

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Added by Christopher Morin on October 24, 2012 at 10:00am — 1 Comment

Humidification: Forced-Air Systems

Months fly by, and it is closer to Fall in New England.  Soon most local Plumbing, Heating, and Cooling companies will be consumed with Fall maintenance programs.  I remember spending countless hours a week dealing with humidifiers, whether it was the old Skuttle drum style, the Aprilaire bypass version, or even the steam models that have actually been improved over the years - particularly Honeywell's Truesteam.  The one…

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Added by Christopher Morin on September 11, 2012 at 1:17pm — 4 Comments

Triple Evacuation vs. Deep Vacuum Method

Deep Vacuum Chart; Carrier…

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Added by Christopher Morin on July 12, 2012 at 11:36am — 1 Comment

Duct Gains: Why do we hate R-8?

Ever since the adoption of the 2009 International Residential Energy Conservation Code (IECC), duct sealing efforts have been tested using the total leakage or leakage to outdoors methods.  It really is amazing how much duct gains effect the operation of your equipment and the comfort of your customer.  The missing part of "duct testing" appears to be how well the ducts are insulated.  Sure, you are required to use R-8 insulation on supply ductwork when located outside the building envelope,…

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Added by Christopher Morin on June 26, 2012 at 1:13pm — 1 Comment

Site Survey: Windows & SHGC

  When completing your site survey for Manual J Load Calculations, significant time can (or should) be spent identifying window values.  Did you know that most windows these days come with an NFRC rating, a tag located in the window jam that you can reference on NFRC.org? This identification number can tell you important details like window coatings, u-value, light transmittance, air leakage, and solar heat gain coefficients (SHGC).  Not identifying the correct values can sway your load…

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Added by Christopher Morin on June 10, 2012 at 6:34pm — 2 Comments

Heat Pump Break-Even COP's

How do you know if  should upgrade your air-conditioner to a heat-pump and create a dual-source application during replacement this Summer?  I personally always prefer the option of multiple fuel sources, particularly since energy prices have been all over the place during the last decade.  Fortunately, based on average energy prices, there is some simple math to figure out if an aggressive assessment should be made for a dual-source heat pump application, based on equations from ACCA's…

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Added by Christopher Morin on June 3, 2012 at 12:23pm — 5 Comments

Diagnosing Improper Fixed Orifice Sizes

   I have found that this topic often goes unnoticed, or can be a guessing game out there in the field.  Diagnosing improper fixed orifice sizes is actually a fairly simple, cut and dry procedure.  First, I would argue for efficiency reasons, as well as ease of proper charging, you should just field install a TXV.  Of course, when you are on the job site you don't want to spend precious time attempting to adjust refrigerant charge with the incorrect orifice. You would never be able to get…

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Added by Christopher Morin on May 23, 2012 at 5:31am — 2 Comments

Correctly Sizing a Capacitor

I don't know how many times a technician has said that they installed a part based on what was on their service truck.  I have heard of technicians wasting money over-sizing contactors, cutting down air filters, and even using controlled substances to clear condensate drains!  Of course, these scenarios all get the job done, but I would argue the many reasons why not to do these.  The one thing that gets to me is when a technician doesn't verify they are installing the correct size dual run…

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Added by Christopher Morin on May 13, 2012 at 11:43am — 2 Comments

Realistic Expectations and "The Occupied Zone"

How many times as a technician have you gone out to the same customer's home because of unrealistic expectations?  Some homeowners expect air-conditioners to work like an ice box, want you to size them for their big party on Fourth of July weekend, and expect you to show up at the drop of a dime when it doesn't meet their impossible notion.  Of course, this could be avoided by establishing a standard during the sales process or a little customer education.  I liked to talk about "The…

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Added by Christopher Morin on May 5, 2012 at 8:07pm — 1 Comment

Energy Efficiency Ratio (EER)

Energy Efficiency Ratio, or EER, is a way to exhibit how well an air-conditioner is operating based on the power being used.  Most homeowners are of course familiar with SEER, the ratio across an entire season.  Since SEER is tested at a "partial load", the EER is a more realistic number to use when figuring energy savings.  AHRI tests their EER of residential air-conditioners using 400 CFM per ton of airflow at 95F Outdoors / 80F Indoors and 67F Wet Bulb.  This compared to the SEER testing…

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Added by Christopher Morin on April 28, 2012 at 6:47pm — 6 Comments

Non-Condensables? Are you sure?

  Non-condensables in a residential split air-conditioner can be, for most technicians, a pandora's box to diagnose.  Fortunately, there is a simple process that can identify this condition without spending hours and hundreds of dollars in virgin refrigerant.  I think we all are aware that R-22 has hit an all time high, so getting this right is more important than ever - if you want to retain your customer.

  There are several ways air and/or water vapor can enter a sealed system. …

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Added by Christopher Morin on April 15, 2012 at 11:30am — 2 Comments

New England; HRV or ERV?

I remember installing some early version residential Energy Recovery Ventilators (ERV) and discovering a potential freezing issue.  Also, if I used only a Heat Recovery Ventilator (HRV) than I would be drying the air during the Winter, and adding significant latent load in the summer.  So, which one do I choose?  The homes are tight enough these days to require mechanical ventilation, and I would much rather a balanced ventilation system that I can control.…

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Added by Christopher Morin on April 9, 2012 at 10:30am — 2 Comments

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