WISDOM PRINCIPLED EMPOWERMENT COMMUNICATIONS © - with Darrell Udelhoven, HVAC-Retired
Publisher of the Series - The Real Political Issues & People Empowerment 
© Edited 07/31/09

Simple Ways To Check Your Air-Conditioner's Performance <Click & Also Cut Home Energy Utility Bills in Half - with Darrell Udelhoven - Save Tons of Energy when Washing & Drying Clothes
Money for mortgage payments - Home Energy Rater Auditing Radio  Program
Cynergy Home HVAC Energy Rater Audits Iowa Public Radio Audio - Listen
Do-It-Yourself Energy Audits
A Major "Oil Furnace" Airflow Problem Fix

You can pay for HVAC service, but may not get reliable servicing of your H-VAC system. That one incompetent service call expenditure would buy all the safe to use test instruments you will ever need, to safely check your H-VAC system's performance.

To ballpark efficient performance, you must know the Cubic Foot per Minute (CFM) airflow of your central system.

To ballpark CFM, I'd use an anemometer & measure the velocity out of those ducts.
If using cheap MPH only anemometer, as you know - multiply by 88 to get FPM.


Use the formula: register face velocity in FPM *X's area in sq.f
6" rd metal duct 6*6=36*.7854=28.2744/144= 0.19635-sq.ft.
7" rd duct 7*7=49*.7854=38.4846/144= 0.2672541-sq.ft., etc.


Add together the number of branch runs to ballpark the actual CFM delivered to the rooms.
Air conditioners  & heat pumps need 400 to 450-CFM of airflow per-ton of cooling.

Get a low cost Testo Tester & anemometer - ballpark CFM & figure actual BTUH & EER - the information on Testo:
http://www.amazon.com/Testo-605-H2-H.../dp/B000774B6A

Everyone, very low cost anemometer to get airflow FPM Velocities, get it:
http://www.amazon.com/Crosse-Technol.../dp/B0002WZRKE


This should be helpful.
CFM X change in enthalpy X 4.5 = BTUH (Ballpark) Operating Performance & EER
"U Must Right Click Link & open in New Tab"
Wet Bulb Enthalpy Chart


Rules of Thumb for Duct Systems  - Hart&Cooley

Google search Hart & Cooley, also this pdf might help you select the right diffuser for the particular application, & list (Ak) free sq.ft., area of the diffusers:
http://www.rileysales.com/hottips/resizingreganddiffuser.pdf


A Major "Oil Furnace" Very Low Airflow Problem - Requires Fixing
Regal & Hallmark & nearly all Oil Furnaces - Installation manuals
http://www.boyertownfurnace.com/ProductDocuments/index.aspx
Download the installation & service manuals
To find the information below; Use within the pdf search:  at least 6” above
Or use down arrow to P-8 & scroll down a-ways...
http://www.boyertownfurnace.com/ProductDocuments/HallmarkONLYManual042909.pdf
"If the oil furnace is used in connection with summer air conditioning the evaporator coil must be installed at least 6” above the oil furnace for proper airflow. Distances less than 6” will result in decreased airflow."
Make sure outlet supply takeoffs are NOT blocked by the coil. In all cases, refer to the manufacturers’ data for static pressure losses to ensure the total system static pressure does not exceed 0
.5” WC.


In summer, Air conditioner & heat pump user's, this is a "Simple Easy Safe Way" to Check an A/C's Thermostatic Expansion Valve  (TXV) metering system's refrigerant charge & any A/C's  Performance:
Record the outdoor temperature, then "Take a thermometer & check the air temperature coming off the outdoor condenser."

A higher indoor humidity raises the condenser temp-split, lower humidity lowers the condenser temp-split.

Depending on the units SEER Rating; all data, AIRFLOW @ 450-CFM per-ton of cooling, Room temps 75 to 80-F,
at 50% indoor relative humidity, the temp-rise for a 12-SEER condenser, should be between around 18 & 20-F; much below that split could be unacceptable.
 
A 10-SEER, at above conditions, 22 to 24-F Condensing Temp-rise
(CT) above outdoor temperature.

A 14-SEER, R-22, 1.5-Ton, Indoor airflow @ 675-CFM, Rooms 75-F @ 50% relative humidity; CT  rise 14-F.
A 16-SEER, R410A, 2-Ton, @ 900-CFM,
Rooms 75-F @ 50% relative humidity; CT  rise 14-F.

Locate the small uninsulated copper line where it makes a bend, outdoors or indoors, so you can put a digital thermometer flat on it & insulate the TH with something (piece of the tubing insulation) read the temperature & subtract it from the outdoor condenser discharge air temp.

E.g., condenser temp 110, line temp 100-F that is 10-F subcooling & 10 to 12-F is a normally charge system. If it's considerably less than 10-F it could be low on refrigerant or need a Tech to check it; too far above 12-F it's overcharged, call a Tech, could also be a restriction in the lines.

A TXV coil will usually show a 9 to 12-F superheat .

The subcooling (BallPark) should be between 10 & 15-F on either a TXV or fixed orifice metered system.

You should own a low cost digital pocket thermometer:
Now the reality is that you don't need a manifold gauge, - anyone can Ballpark check the charge in respect to the indoor airflow with only a little low cost MA-Line digital thermometer using some tubing insulation on the sensor probe. An A/C supply Outlet might sell you one or inquire at hardware stores! Saves money on needless A/C Service Calls!
http://www.ma-line.com/HTML/L1_productmenu.html

Take the outdoor temperature & subtract it from the outdoor condenser's discharge air temperature.
This temperature is standard for different SEER Rated units.

A 12-SEER unit, with 50% relative humidity indoors will have ballpark, will have an 18 to 20-F temp split
A 14-SEER will be around a 14 to 16-F temp/split. if too far above or below those temps, call for an A/C Tech.

Money for mortgage payments.

Cynergy Home HVAC Energy Rater Audits Audio  Affordable Test Instruments Techs Need
Excellent Public Radio Program Above - Listen & Learn While Reading!
It is critical for Broadcast media to launch an all out PSA campaign to Cut Home Energy use in Half; that will also lead to lower energy prices. This is the low energy cost way, Not Cap&Trade way- that could lead to high energy prices  & more unemployment & stagflation!

Natural gas is used to dry clothes & heat water, Plus to generate a lot of electricity. Reducing its use, will reduce the remaining lowered heating use, per unit cost; a Win/Win Equation for everyone.

With mass media cooperation, it can become, ("IN the Public Interest"), a tremendous Mutual Win/Win on a global basis, plus it will greatly Reduce our carbon footprint pollution equation!


Buy indoor & outdoor clothes racks & pincher clothes pins, then dry clothes in a room in your home or hang in good weather on a line in your back yard; I never use my electric clothes dryer. It's easy to do & fun when you see how much money you will save!

Drying clothes indoors helps humidify your home in cold weather.

To remove wrinkles from a few fabrics, briefly use dryer's low heat wrinkle removal mode.

In warm weather if there is a code against outdoor clothes lines where you live, simple use your indoor clothes rack in a room with the windows open & a 20" Wind Machine vertical adjustment floor type fan blowing on the clothes.

Those blowers use about what a light bulb uses, compared to your dryer, that is nothing!

Wash clothes in cold water that you draw after the last washing, so it warms to room temperature.
Well prior to washing, put detergent in washer's cold water & cycle it for a very short time & agitate for a couple minutes, then shut off & leave stand for hours, then wash clothes & they will be super clean. I never use any hot water to wash clothes! Just these Two things with a family will save a ton of Energy & Money!

Heating water & using a clothes dryer are huge energy eaters; you can drop your utility bills in half or more!

=============================================================
Identifying your registers/diffusers & their (Ak) sq.ft. area, so you can multiply the FPM Velocity times the Ak to get the (CFM) Cubic Feet per Minute airflow from that register.

http://www.americanmetalproducts.com/lima/product_catalogs.html
Click on the categories to see the diffusers & Return-Air Grilles then find them on your downloaded pdf's engineering data.
Hart & Cooley: http://www.hartandcooley.com/grd/HC-100/residential/baseboard_registers/462.htm
Do a lot of Hart & Cooley engineering data searches, look at the registers & the Ak sq.ft. data to figure register's delivered CFM.
=============================================================
Home Energy Magazine Online September/October 1993 
Raising Standards and Savings
New Group Hunts Bad Ducts (A/C duct systems)


Does 40 billion kWh sound like a lot of energy? How about 4 billion therms? Researchers believe that's how much electrical and gas energy this country "could save by fixing inefficient ducts using current techniques." "Refining those techniques could reap savings of 90 billion kWh"plus 9 billion therms! Peak loads would be reduced too. To pursue these tremendous savings, national, state, and utility research laboratories, the U.S. Department of Energy, utilities, and energy service companies are collaborating. Their consortium is called "Residential Energy Efficient Distribution Systems," or REEDS.

These techniques, along with reducing air infiltration & heatgain/heatloss calcs, ought to be taught in all our schools as part of the Science & math curricula. Half the heatgain/heatloss can be due to a high Home Air Infiltration Rates!
ASHRAE standard 62-1989 is 0.35 ACH (Air changes per Hour) or 3-hours for a total interior, Air INFILTRATION Change.
Home Air Infiltration
Air Infiltration sources DTI Corp Catalog
DTI Corp Air Infiltratrion
--------------------------------------
http://www.energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11250
DOE Reducing Air Infiltration Information
May add more later.

============================
Milwaukee Energy Efficiency (Me2)
The potential is great and the model is simple: The Milwaukee Energy Efficiency (Me2) program would allow building owners and occupants to pay for the cost of improvements as a charge on their municipal services bill or utility bill, on a schedule that allows them immediate savings.

If a participating building owner or occupant leaves the property before repayment is complete, the remaining obligation can go to the next owner or occupant as he or she benefits from reduced energy costs. The program will create thousands of good jobs — ranging from entry level to highly skilled — and fill them locally.  Milw. WI
------------------------------------
If your monthly cooling bill is very high & you want to cut it in half or less; start with an entire home energy use & the HVAC Evaluation listed below.

Cut air infiltration to a minimum, a Blower-Door-Test will locate the air leak areas; a Duct Blaster to detect duct leaks & size ducts to optimize airflow.
Check for window options along with outdoor window shutters or awnings.

Half the heatgain/heatloss can be due to a high building air infiltration rate!
- Source Home Energy magazine online Sept/Oct 1993
http://www.energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11250
- DOE Reducing Air Infiltration Information
----------------------
The ductwork system & airflow must be accurately checked & optimized.
Refining those ductwork techniques could reap savings of 90 billion kWh" plus 9 billion therms!
- Source Home Energy magazine online Sept/Oct 1993
-----------------------------------------------------
*To check your A/C system you need a thermometer, wet cotton cloth, or a humidity gage.
At a hardware store, it is around $10 for humidity gage & thermometer combo.
Keep the Temp/Humidity combo gage indoors.

Then check the condenser fins, they must be clean.
*** Absolutely Disconnect all the power 230-Volt breaker power to the condenser, including the furnace power for the low voltage in the condenser!

If you use water pressure, keep the stream in-line with the fins so it does not bend them.

Let it dry for a long time before operating for ten minutes or longer, then take the temperature readings.
Let it dry out for several hours before reapplying power &/or using the A/C.

The A/C user need not know all the tech info, all they need to know are a very few basic simple ways to identify that the system is not functioning correctly so if necessary you can call for a pro-tech to properly trouble shoot the system.

Now the reality is that you don't need a manifold gauge, - anyone can Ballpark check the charge in respect to the indoor airflow with only a little low cost MA-Line digital thermometer using some tubing insulation on the sensor probe.
http://www.ma-line.com/HTML/L1_productmenu.html 
You can't order it there.


However First, you check the discharge air temp off the outdoor condenser, (that is the "Condensing Temperature (CT)," the higher the SEER Rating the lower the outdoor normal temp/split above the outdoor temperature will be.)
Then you either check the small liquid line tubing temp outdoors where there is a tubing bend, or indoors where it bends to enter the plenum. 


Indoors could be inaccurate as the tubing temp could vary higher or lower depending on temp conditions the line is conducting.

Subtract the small liquid line temp from the CT & you have the Subcooling temp which varies some from mfg'ers, but will be Ballpark 8 to 12-F Subcooled.

The condenser temp (CT) above the outdoor temp tells you how much indoor sensible & latent heat, & the 3 motor heats it is ejecting. The indoor humidity level has the biggest effect, the higher the humidity the higher the split.

Now, indoors the higher the humidity the lower the temp/split between Supply-Air & Return-Air.

At 50% indoor humidity the split should be Ballpark, around 18 - 20-F.

If blower wheel blades & all coils are relatively clean & the split is well above 20-F, you have low airflow with a low heatload through the evaporator coil.

If the indoor split is way below 18-F at 50% RH, you either have way too much airflow or some problems in the functioning refrigerant system.

To solve any of these problems you need to call a knowledgeable HVAC TECH! - Darrell U
==================
DESIGN AND INSTALLATION OF RESIDENTIAL FLEXIBLE DUCTWORK SYSTEMS
http://www.dca.state.ga.us/development/constructioncodes/publications/1ONE.pdf

Look at the ducting, if it is not to code; make hard copies of this code & give it to whoever does the ducting work.
Make sure they get redo it right!
Never have flex duct interiors commercially cleaned, I just viewed Home Inspection photos showing the interior damaged & insulation plugging the duct.
Home Inspectors warn people because the duct cleaner's tell them it won't damage the ducts. Some HI's look into the boot areas for clues of problems...

==================

On a normal temperature day & indoor temperature, check the humidity & temperature indoors & record it.

Then check the outdoor temperature, & the temperature of the condenser's discharge air.

Subtract the outdoor temperature from the discharge temperature to get the split.
Then you go by SEER Rating for the temp-split perimeters.

Try to check your A/C when conditions are 85 to 95 with indoor temps between 75 & 80-F, with around 50%RH.
Depending on indoor conditions, e.g., lighter loads; the split could be 2 to 3-F below the listed temperature.
All ARI Conditions 95-F out doors, 80-F indoors @ 50% RH (between 75 to 80-F is okay)

For 12-SEER Units=IndoorTemp-Split @400-CFM Per-Ton of Cooling 50% Relative Humidity|SA/RASplit |
18-F| CONDENSER TEMPERATURE SPLITS - Above Outdoor Temperature
1.5-Ton  18,000 Outdoor temp 95F; 80-F IDB, @ 67-F IWB or 50% RH; ARI Conditions = 21-F Condenser Air-Temp-Split.  Don's @10-F to 12-F Split - Low ID Airflow!
1.5-Ton 18,000 18-F to 21-F Temp-Split    Condenser CFM 1400
2-Ton  24,000  22-F T-Temp-Split  Condenser CFM 1400
2.5-T  30,200  20-F Temp-Split     Condenser CFM 2000
3-Ton  35,600 17-F Temp-Split     Condenser CFM 2800
3.5 T   42,000 18-F Temp-Split    Condenser CFM 2800
4-Ton  48,000 18 -F Temp-Split    Condenser CFM 3400
5-Ton  59,000 22-F Temp-Split     Condenser CFM 3400
CFM is Cubic Feet-per Minute of airflow through the condenser.


Goodman data for R-22, 14-SEER Units;
1.5-Ton 17,600-BTUH; 2.54-Ton evaporator coil, TXV; Single Stage:
Outdoor Temp 85-F; IDB 75-F; Humidity 52%; Indoor temp-split 19-F; Condenser Split 11-F; 675-CFM


Goodman data for R-410A, 16-SEER Units; 2-Ton 22,800-BTUH; 3-Ton evaporator coil, TXV; Single Stage:
OutdoorTemp 85-F;Indoor Dry Bulb 75-F;RH52%;14-F CondenserTemp-Split;IndoorTemp-split 21-F;
800-CFM
-----------------------------------------

Indoors:  Return Air Entering Temp: ____F  - Coldest Nearest A-Coil Supply Air temp: ____F  Temp-Split ______F   Relative Humidity ______
Or, Wet Bulb Temp __F Outdoors: Outdoor condenser discharge Air Temp: _______F  - Outdoor /Temp ______F   Temp-Split ______F

You can use a piece cotton cloth (etc.) soaked in room temp water. Set a hi-spd fan near the return air intake & wait until you get the lowest wet bulb temp. That's the Wet bulb temp & it's what I used to take with a sling-psychrometer. So, rig one up & just give me the wet bulb temp; wet bulb can also converted it to %RH.
Copy above&use, it's FREE; You must link to this page or Cite Source To Tweet or publish this material:



---------------------------  E-mail me the data: udarrell**@**pcii.net
This tells you the nominal amount of heat (BTUH) that is being absorbed by the indoor evaporator coil & being discharged by the outdoor condenser coil.

With outdoor & indoor coils clean with clean blower wheel blades & filter; If the outdoor condenser temp-split is low, & indoor
Return-Air temp minus Supply-Air temp is high, then there is NOT enough airflow heatload going through & being absorbed by the indoor coil.

If the condenser discharge air is within the nominal range, +/- 2-F, then the system is absorbing & transferring a nominal latent & sensible BTUH amount of heat from the interior of your home.

In this simple test procedure, the (1) Temperature-Split of Supply & Return Air, & (2) indoor humidity reading & the (3) outdoor condenser discharge air temp-split is all we need.

With the combination of the outdoor split & the indoor Supply-Air/Return-Air temperature splits & the room Relative Humidity Percentage, I can tell you if the indoor airflow is in the normal range.

Normal Supply-Air/Return-Air temp-split is 16 to 22-F. A heavy humidity load will take the split down toward 16-F. Dry air will have a high temp/split 22-F or a bit higher.

What can skew this test is a dirty indoor evaporator coil. In that event, the blower wheel blades will be dirty too, so with power off, check those blades!
Always do these temperature checks with a clean filter installed.


An airflow velocity meter is a great instrument to have; they're not very expensive.
Formula for finding CFM Airflow
Quick method: The heat gain and Btu/hr of cooling is done for each room.
At 400-CFM per/ton of cooling, 12,000-BTUH / 400-cfm = 30-BTUH for each (CFM) Cubic Foot per Minute of Airflow.
At 450-CFM per/ton cooling use 12,000 / 450-cfm = 26.66-BTUH per each CFM, etc.

Then Select Supply duct size by CFM, velocity, & optimal Supply Air *(FR) Friction Rate.

A Room requires 3000-Btu/hr divided / by 30 equals 100-CFM, or around a 6" dia. RD metal duct.
You need-> Five duct runs for 1.5-ton unit, 18,000-BTUH: (Equal room loads,ha!) 18000 / 5-runs= 3600-BTUH / 30 = 120-CFM each 6" duct velocity 611-fpm Velocity. 18' length branch runs 611-fpm velocity at a Friction Rate 0.03" per 18'.


The total airflow should be in the range of 375 to 450-CFM per ton of cooling; Unless you have high humidity I'd go for 425 to 450-CFM per ton of cooling!
One ton is *(12,000-BTUH).

*Check the Return Air filter(s) often, need optimal airflow especially during a heat wave!
==============================
An Affordable Test Instrument You Need!
All I had was the Sling Psychrometer & spinning it was a bit time consuming, but I used it religiously, it is information you need. 

The Testo 605-H2 Humidity Stick (wet bulb), displays relative humidity, air temperature and wet bulb temperature.

It is very affordable & because of its potential to help deliver tons of other data everyone should have one!

For more information on it:
http://www.amazon.com/Testo-605-H2-H.../dp/B000774B6A

The other test data you need is the system's CFM airflow through the evaporator coil, then with software I have you can peg the BTUH the operating unit is delivering under those conditions.
Add to that a low cost Magnehelic gauge to read static pressures to compare with mfg'ers blower performance charts; plus a velocity meter & you have a ballparked CFM to plug into for the BTUH.

We could easily provide a detailed psychrometric print out of exactly what the operating system is delivering including condensate lbs/hr, & actual sensible & latent cooling BTUH & Ratio, every data detail imaginable. - Darrell

----------------------------------------------------------------
DISCLAIMER:
I do NOT assume any responsibility for how anyone uses the information on my Web pages.

All HVAC/R work should always be done by a licensed Contractor! This information is only placed on these pages for your understanding & communication with contractors & techs.

This information is for the edification of contractors and techs. I am NOT liable for what you do, you are liable for what you do!  - Darrell Udelhoven

Darrell's Refrigeration Heating and Air Conditioning - Federal Refrigerant Licensed - Retired Licensed Contractor

 

Please write me if you have anything you'd like to contribute! - Darrell 

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    Empowerment Communications
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    Posted: 05/03/09; Edited 02/09/10