Category Archives: HVAC

Keep the AC going on hot summer days.

Want to know if you air conditioning is working properly? Wait until it gets hot and then you will find out. If the AC can keep up to the load, then it is likely working properly.  If it cannot keep up or quits then you got issues. The hottest days of the year, is a bad time to call the for the AC guy, there could be 100’s calls ahead of you.

Air Conditioning systems, are sized to work on what is expected to be the hottest days of the year, which is about 97.5% of the time, for your area. This is the design temperature, that the engineer used to determined the size of the air conditioner. At this temperature, the amount of heat that is gained in a building, will be equal to the amount of  heat being absorbed by AC.  If more heat is gained, than can be absorbed, then the room temperature is going up.  The designer will allow for a little more capacity, and use a 10% safety margin and will select up,  the next available equipment size, above the design requirements.

If the compressor is running continuously without cycling off,  your AC is running at maximum capacity. This is normal on very hot and humid days. If the AC cannot keep up or if it is not the hottest days of the year, and your AC is running continuously just to keep up, then there is a problem.

There can be a lot of hidden issues with an AC system that will reduce efficiency but do not get noticed until weather gets hot. This loss of efficiency, affects your AC all year and it can cost you twice as much for electricity.  It can also damage the compressor and controls and will most likely to fail, when it is in highest demand, on the hottest days of the year.

Image of a AC system used in residential housing
Typical split AC system

AC Tip.

Two piece air conditioners have an indoor coil and outdoor coil and compressor. The two are connected with two copper pipes, a big pipe and a little pipe. The big pipe should be cool (~60°F to ~50°F) and the little pipe should be warm. (~80°F to ~90°F) If the big pipe is cold, ice forming on the pipe or the pipe is too warm then there could be a problem with the refrigerant charge.

If the little pipe is hot, then the condenser could be dirty or over charged with refrigerant. If it is too cool, where the line connects to the indoor coil, there could be a clogged filter, pinched line or  it could be under charged.

These problems can only be repaired by a qualified Refrigeration/AC Technician. Do not attempt to repair these systems yourself.

Commissioning Authority

I have been in the HVAC Industry for 30 years and the amount of nonsense that goes on in any given project, never ceases to amaze me. Projects that run ridiculously over budget, technical equipment not functioning as designed, engineers that lower the bar to account for mistakes, and numerous other deficiencies that are passed on to owners.
The Construction Industry has changed extensively over the past 10 years, building structures and its systems are more complex. Systems such as, Communication Networks, Computer Servers, Surveillance Equipment, Building Automation, Sprinklers, Fire Alarms, tighter building envelops and complicated HVAC to mention a few. Added to this mix, are many new building codes that demand higher efficiency and stricter safety requirements. All these changes necessitate a higher level of skill which is increasingly difficult to hire as the skilled labour pool continues to shrink.

During this same time period, I have seen millions spent poorly and millions, needlessly added in future operating cost. Many owners and tenants have been disappointed to put it mildly. Had there been better planning in the beginning, a little more watch over the work site, during construction and proper commissioning on completions, a large amount of this money, could have been saved or, at the very least, better invested. Many new tenants and owners, would be much happier if they got what they paid for, instead of being stuck unexpected additional costs.

dirty filter-3
Heating Loop side stream filters

For example, this image is a water filter from a hydronic system. The building was less than 3 years old and there are serious mechanical issues. The mechanical system likely cost a million+ and, a particular filter was specified but never installed. The filter housing is worth $100.00 and was installed on the heating loop, afterwards. It was in place for about 2 hours before being pried from the filter housing. The muck on the filter is mostly iron combined with other contaminates. Some of the muck has been caught in the filter, much more can be found in every bearing, pump, sensor, valve, boiler and heat exchanger in this building. It will be almost impossible, to completely remove the material, the best you can do is to reduce it. It will cause damage to this mechanical system, for years to come and should have never been allowed to occur in the first place. The missing filter was not the cause of these issues but would have reduced the damage. In this case, the developer had a reputable design team, an experienced general contractor, and basic commissioning at the end of the project. So why did this problem occur and how would you prevent it from occurring again?

Would you like to know more?