Ever wonder what the HVAC "guy" ISN'T telling you

, that which he could to promote #Energy efficiency as well as longevity for you equipment?

We thought this through with an actual homeowner to get her opinion.

What she said:

They don't tell you that you can do some basic maintenance yourself, they want you on their service plan. · The Basics: All HVAC equipment, especially residential is based on very basic science. The number one tenement of those principles is Heat Transfer capability. By keeping the coils clean from debris, dirt, ant beds, etc... you can really help your systems cool as efficiently as possible, especially the outdoor unit that us most likely lurking behind the Azaleas. A simple routine of turning off the power to the outdoor unit and flushing the coils, the thing that looks like a radiator, can really help keep you in much better shape. This address' the first point of:


Point # 2: They don't tell you that you can install a programmable thermostat yourself.

A higher-end programmable thermostat can be a great ally for you and your space, work or home, in saving money by reducing the operating hours if the HVAC system. These thermostats are fairly easy to install, usually a direct wire to wire installation. Hint: Make a drawing and label the existing ones as you disconnect them. There are even WiFi enabled thermostats that allow for remote connectivity, these are a great fit for a weekend home or a remote office with little traffic. You can dial in the desired set-point before arrival as well as check the settings after your weekend guest leave to ensure things are back to normal.

 Point # 3: They don't tell you the best programming for your thermostat.
Obviously this will require tweaking based upon your personal preferences, do you like it a little warmer or a little cooler than the average bear? 75*F or so should be a great starting point, you can adjust up or down to suite your needs, same for heating, try 69 as a start and go from there. 

Number 4: They don't tell you the best programming for your thermostat.

We suggest a five degree rise or lowering mark as a starting point. The goal is you do not want your equipment running any more than required while you are away, but you do not want it so far from set point that it has a hard time recovering either. Five degrees will save you a lot of power and allow for a graceful recovery. Over time you can continue to adjust up or down accordingly, remember, every minute that your equipment is off, it isn't costing you anything.



Five: they don't tell you to check your condensation pumps and drains regularly to keep from getting water damage.

Insurance companies will tell you the most expensive claims are those involving water. One way to ensure that you keep your claims and therefore your insurance costs in check are by ensuring you are doing what you can to keep the HVAC system draining well. Dehumidification is a naturally occurring benefit to air conditioning. You remove heat out of the air stream by having a cooler surface for the air to interact with that is cooler than the ambient air temperature. With the laws of physics, it so happens that in order to cooler houses, buildings, data centers, etc... That cooler surface is the evaporator coil of your HVAC system. In a normally operating unit, the coil temperature is around 40* F, plenty below the dew point temperature of the air in your house or office. As the warm air collides and moves through the coil, most of the moisture within it falls into the drain pan where it is removed from the coil area. These drain pans and the associated drain lines and condensation removal pumps can be maintained by the end-user or home owner. A simple 50/50 solution of household bleach and tap water dumped into the drain pan periodically, maybe twice during the summer months, can possibly save an overflow of the drain and stop an insurance claim from occurring.

 
Lastly at # 6: They don't tell you they'd rather convince you that you need a newer system than work on older equipment.

The HVAC industry in not all that unique from other industries in regards to craftsmanship ... Better said, the dying art if craftsmanship. The industry at large has seen a shift over the last 20 years or so and has become dependent upon "parts changers" versus the tradesmen who over the years have devolved and utilized craftsmanship to ply their trade. The down side to that can be witnessed in the industries obsession to replace versus repair broken HVAC systems.

Yes there are many times that a system could benefit from a new indoor, outdoor or both unit. Energy use, age, general conditions should dictate these decisions, not the lack of talent by the guy performing the diagnosis. So, if you are told, "you just need a new one", don't be shy about refusing that and asking for a proper repair of your existing unit.

Keeping the image of any industry in the right light can be challenging, we are only as a good of a group as we are as individuals. Not all contractors or "HVAC Guys" are described above, in fact, our industry is full of well-known and not-so-well known companies and people.

Like in any other aspect of life, do your homework, find the right person/company that suites YOU and build a relationship with them Friends always take care of friends.



Read, Learn & Share

 

Have you ever been asked or ever wonder, "Is Refrigerant, especially R-134a, heavier than air?

Is Refrigerant Heavier than Air You Ask

I was asked just this week this very question.  Thinking I knew the answer right away, I was able to contain my natural, blurt it out style of an answer, at least until now.  Now that I have indeed verified this data and not relied upon my 49 year old, filled with million of bits of USELESS Data, brain to produce a quality answer.

Yes is the correct answer, Refrigerant, and in this case, I am speaking specifically to and about R-134a, but it is a typical gas.  Always check with the or a refrigerant manufacturer, as the chemical composition of R-134a is all the same regardless of the name on the canister, it is just branded as, Freon or Aspen and a host of other "Names to Make You Think Col or Cold Thoughts".

If you are curious for the actual verbiage, see section 7.1 of the MSDS that this link will take you to.

DuPont, the Original "Freon Brand" of Refrigerants MSDS on Refrigerant 134a

Why does this matter to people?  Well if you are a building manager or the safety officer within you company, this could be an integral part of your safety SOP's and or helping people understand what to do in the case of a reported refrigerant leak into the office space.  Knowing that these refrigerants will lie close to the floor versus rising within the occupied spaces could be very helpful.

Secondly, if you have a refrigerant evacuation duct system, some instances are dictated by state and local mechanical codes to do so, it will help you understand why it is important to keep the intake grills free of obstructions and debris.

Lastly, if you operate a building of any size, you may want to consider how many other people handle and are prepared for refrigerant related issues.  Having a Refrigerant Management Process is a great idea. 

The link below will take you to an example of how California regulates stationary HVAC systems and the associated refrigerants are to be handled.  Know your local code, that is the only way to ensure that you are covered.

Refrigerant Management Process Link to Info

Remember that each local jurisdiction can and frequently does act independently of any other party.  Different refrigerants also have different characteristics insofar as Global Warming Potential, GWP as well as Flammability levels and ODP, which is Ozone Depletion Potential. We all have a responsibility to handle refrigerants in a safe way to us, others as well as the Earth herself.

Learn and understand what refrigerant or refrigerants, as many buildings contain multiple units that can utilize unique refrigerants, that you are responsible for or have the potential to be exposed to.

Like everything else, knowledge is the key to understanding, then educating others.

I truly hope this will help you structure or refine your system or process.



VAV versus PIU, have you ever had to try and figure out the difference?

 

VAV versus PIU, .... WTF (Where's the Fan)?

 

 

 

In many commercial Air Conditioning Air Distribution systems, there is a strange phenomenon.  That is, what is a VAV and what is a PIU and why do many people call all of these one or the other?

 

Great questions indeed.Unlike your home, commercial and/or industrial duct systems work at substantially higher internal duct air pressure, this is called static pressure.  Static pressure allows the air to flow (move really) from a higher pressure within the duct system to a lower pressure area within the duct system.  This creates the air flow that we all love to feel when we are hot.

 

In the common fan unit, it can be called an Air Handling Unit (AHU) in many instances, but could located within a Roof Top Packaged Unit (RTU) or a built up air handler, this is where many components are assembled in the field to make an AHU, usually on rather large equipment, there is a fan of some variety that produces static pressure.  This fan(s) could be a typical fan as you would have in your furnace (Forward curve), a backward incline a fan axial, etc... Many types, all trying to do one thing, produce static pressure within the duct to allow the Air Distribution System to deliver air flow.

 

The Air Distribution System is made up of the fan, as we discussed above, the duct system as well as incorporates all Terminal Units.  These terminal units are the VAV's and PIU's that brought us here to begin with.

 

                          VAV = Variable Air Volume     PIU - Powered Induction Unit

 

Both of the devices incorporate a damper than automatically adjust the air flow when the building controls (#Tridium as an example) ask for cool air to be delivered into the space that particular VAV is serving.  These areas being served are referred to as Zones.  In most modern layouts and engineered buildings, the VAV's serve the interior parts of the building, the areas that typically do not require heat.  The heat in these areas is provided by lights, people, solar warmth, etc...

 

The PIU is an assembly that takes the same concept as the VAV, but once the controls tell the damper to close due to the space set point being satisfied, the PIU will in fact completely close the medium pressure air from the duct system then start a small internal fan that will recirculate return and/or plenum air to begin to temper the space if the temperature still continues to fall, once the fan moving this non-cooled air cannot suffice, the PIU can start to heat, many times this is a single or multi-stage electric heating element or possibly steam or heating water.  These PIU devices are typically located within the exterior zones of a building where heat is required to keep the occupants and or goods at a comfortable temperature.

 

Knowing a bit more about what is lurking above the ceiling tile may never wind up helping you in your day to day, but at least you will have a good idea of whom to call if things were to get hot and sticky in the office.

 

For more on HVAC for Office Buildings, Data Centers and any Mission Critical Environment, please visit or The Tech Corner @ http://www.airtight.co/the-tech-corner/

 

 

DISCLAIMER:  Verbiage within our wacky Mechanical Industry can vary greatly, I have tried within the post to capture the general essence of what "most" people call "most" of the devices.  We try to get along, this is what happens when things go wrong!

 

 

 

 

 

 





Someone just said, "The SWUD Unit is down". What does that even mean & why is it making the building HOT?

SWUD:  More than just an acronym

Back in the 1990's, the Trane Company, now part of Ingersoll-Rand, introduced a line of Environmental Unit's designed to condition low & mid-rise buildings.  These units model numbers began with four letters ... You guessed it , SWUDU9042**BC360095BB101, as you can see if you do not have a Trane operations & maintenance book handy, the short cut to defining what this unit is would be simply to call it a SWUD unit.  These systems have gained in their sophistication and the markets served and now are commonly used in high-rise building applications.

The design of these systems are very compact and deliver a great punch for the limited foot-print that they consume in regards to floor space.  SWUD-style units have a complete mechanical system built within them to allow for the total conditioning of an office environment with the exception of the heat rejection component.  Either a cooling tower or a remote condenser. 

Just like in any home or office, laboratory or data center air conditioner, there a four required components to provide "cooling".  The Compressor(s), Condenser, refrigerant Metering Device, commonly refereed to as a TXV or a TEV and lastly the Evaporator, this is the section where the heat from the air stream jumps into the refrigerant in order to produce the cooling effect that we all need this time of year.

The basics of refrigeration are not all that basic, if you would like, please let me know via @gregcrumpton on Twitter and I will dive deeper into the particulars on the vapor compression cycle (refrigeration) itself.

The gist of this note is to allow you to understand that a SWUD unit, usually resides in the mechanical room of your building, is connected to a medium pressure duct (air distribution) system, works in conjunction with the buildings temperature controls and 9 times out of 10 is connected to a common cooling tower that serves as the final point of heat rejection from the building into the atmosphere.

This is a real simple explanation, but knowing the acronym may allow you to know whom to call if indeed you are hot and sticky at work.



Air Filters for Dummies: The Guide to Changing Your Air Filter

Air Filters for Dummies

Have you ever wondered when, why and if to change your air filter(s) at home or in the office?  Sometimes your thermostat tells you ... How does it know when?  Sometimes you happen to think about it when you see those ugly blue filters in the grocery store.  And then, you really think about it when the A/C stops working and the technician shows up and the culprit is ... You guessed it, Dirty Air Filters.

Back to basics:

Air filters are designed to catch fairly large, it is all relative, particulate out of the air stream.  Most filters are great at catching dust, per hair, etc...  The "ugly blue" air filters are really great for catching pigeons, children and other items of that size, not so good at removing the proper sized particulate from the air stream though.

To really help with dust control, pet dander, and pollen, we suggest using a pleated air filter, it has more surface area, due to the folded pleats designed into it and does a much better job than old blue.


Why are air filters really designed into an HVAC system?:

Air filters are designed into the total HVAC system for only one reason:  It isn't to control the dust on the end-table ... The main purpose of these filters is to prevent the dust and debris from collecting on the face of the coil (heat exchanger) of the air conditioning portion of the system.  The refrigerant (trade name Freon) in the system requires that heat be transferred from the air stream into the refrigerant circuit, it can only do this efficiently when the entire coil surface is clean and available for this exchange.  The natural by-product of air conditioning (cooling) is dehumidification, hence when dehumidifying, the evaporator (indoor coil) is wet with condensation, this would really gum-up with dust and grime if the filter was not there to PROTECT the coil surface.  That is the entire purpose for the filter, all of the other benefits we enjoy are just icing on the cake.


The BIG question ... How often to Replace the Filter(s):

As i said above, sometimes your thermostat will tell you to do it ... It is simply guessing.  It uses a hypothesis to say to do it based upon hours of operation, not "dirtiness" or pressure drop or anything scientific.  This is really a convenience feature that is there to simply serve as a reminder to do it.  We suggest changing the air filters in your home and office environment quarterly, four times per year.  Most residential systems only have one or a few filters, many office buildings have a much larger count and therefore will need to be considered in the budgeting process.  Your HVAC service contractor can help with the value to add in for that replacement program. 

The other thing to consider:

Ina commercial office building, there are systems that allow you to induce outside air into the space as the primary cooling source.  This is called an air-side economizer, there are water-side economizers as well, but that is for a different day, these will require a little more monitoring of the air filter condition due to the high percentage of ambient air that is being puled through the filters.  The economizers are a great money saving tool and even though the filter replacement cost will increase with use, your overall power consumption will be reduced so far, there will be a "No Brainer" conversation to be had.  For more on Economizer Use Read about it in a past Newsletter @:  www.airtight.co/newsletters/AirTight_Newsletter-April_2012.pdf

Wonderng where these terms came from?

 

Common Questions Regarding HVAC Terminology & Applications

 

Over the years, many people have had similar questions to common thoughts. During my 30 plus years, I have catalogued many of these. Seems to be a great time to start eking them out, summer is here and the mighty HVAC industry roars!

Ø Why is it that I hear people talking about how many “Tons” their HVAC unit is? Is it that heavy, does a 3 ton system really weigh 6,000 lbs?

ü A ton of refrigeration is approximately equal to the cooling power of one ton (2,000 lbs.) of ice melting in a 24-hour period. The value is defined as 12,000 BTU per hour, or 3517 watts.

The original design utilized a big block of ice, roughly a ton of it, then a fan, either electrically powered or otherwise driven would blow air over the ice, the air would surrender its heat to the ice, thus melting it, then the now cooler air would be delivered to the place people had gathered, typically in places of worship or community gathering sites. These values were established long ago before the mass use of centralized systems. There are many variations, designs and styles of units and complete systems. Large, small, water-based, refrigerant-based, etc… For more information and further details, visit: http://www.airtight.co/the-tech-corner/technical-glossaryand/or https://en.wikipedia.org/wiki/Air_conditioning

Ø What is the part of the A/C system that sits on the roof and/or behind my house in the shrubbery?

ü It is the Condensing Unit with the Condenser Coil within the cabinet. A condenser coil is one means of heat rejection commonly used in an air conditioning system. It is typically located on an outdoor pad or on a rooftop and looks like an automobile radiator in a cabinet. It is usually hot to the touch (120°F / 49°C) during normal use. Its function is to transfer heat energy from the refrigerant to the cooler surrounding (usually outdoor) environment. Yes, even when it is 100 degrees outside, it is still cooler than the refrigerant that is circulating with the tubing. The more commercially related Dry Cooler or Fluid Cooler serves the same purpose of heat rejection and physically appears similar, with the difference that the condenser coil uses hot refrigerant which changes from a gas to liquid as it move through the coil, whereas the Fluid Cooler uses hot liquid such as water or a water-glycol mix.

http://www.youtube.com/watch?feature=player_embedded&v=IF5WORhyXj4

These coils typically require an annual cleaning with water and/or a solution, determined by the particular manufacturer. This cleaning will keep the heat exchange rate within normal limits, thus saving energy consumption, therefore power and keep the system cooling at optimum levels. This cleaning should always a part of your Preventive Maintenance program.