Archive for November, 2011

Sediment traps at water heaters and furnaces

Tuesday, November 22nd, 2011

A question I get asked about frequently is what is a sediment trap, and what is its purpose. I have installed a number of water heaters over the years and have found that within the last 4-5 years, all water heater manufactures recommend installing a sediment trap. If you do not install a sediment trap on your new water heater, it will void the warranty. The installation of this trap at the water heater as well as the furnace is also a requirement of the Claifornia Plumbing Code; 1212.7

 

The installation of a trap is a safety feature, and can extend the life of your water heater or furnace. What a sediment trap does is keeps moisture and small particles that may be in the natural gas or propane from clogging the small orifices that are within the gas valve assembly at the appliances, and the burners as well. The gas valve assembly for a water heater is where the temperature selection knob is located. If any of these orifices get clogged, the pilot for a water heater, and or the burners for both the water heater or furnace will not operate correctly which could lead to a hazardous condition.

 

  A sediment trap should be as close to the water heater or furnace as possible, but down stream of the shut off valve for these gas fired appliances. This is so the gas can be shut off and the trap checked if necessary. The trap is installed where the gas flow must make a 90 degree turn just before the gas valve assembley. In order to prevent clogging, moisture or particals in the natural gas, or propane gas will settle in the trap. This trap is simply a short length of pipe (or nipple) facing downward that is a minimum of 3 inches long, is threaded at the bottom that is capped.This is a very inexpensive component, and only takes a few minutes to install, but provides safety, and prolongs the life of the appliance. 

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Testing air conditioners during cold weather can damage the system

Monday, November 7th, 2011

It is often asked why home inspectors do not test air conditioning systems during the cold months. Without getting into the specific science of how an air conditioning system works, it is primarily a science of the compression of gas into a liquid, and expansion of this liquid back into a gas. These two functions occur at the condensor coil, which is large piece of equipment located at the exterior of the building, and the evaporator coil that is located at the furnace. When the outside temperature is too cold, (or sometimes even cold indoor temperatures), it is possible the gases in the air conditioning system's "suction" portion of the refrigerant line can turn to a liquid. Turning on the air conditioner when the gas is a liquid can cause the liquid to "slug the compressor" which can cause damage to valves within the compressor. The compressor is a component of the exterior condensor coil, which is the large unit on the outside of a building that also houses a large fan. Depending on the specific manufacturer, the lowest temperature where it is advised not to operate the system varies between 50 degrees and 65 degrees, in a time frame that also varies anywhere from 12 to 48 hours prior to turning on the system, it all depends on different brands. As general home inspectors, we use the lowest common denominators. It is possible that Heating and Ventilation contractors (HVAC) also may not be able to test this equipment if the weather is too cold. Some types of air conditioners have components built into the system that prevent the gas from turning into a liquid during the cold weather, however, as home inspectors we are not qualified to, or for that matter able to visually identify this particular type of feature. When purchasing a home warranty, it would be prudent to make sure this warranty includes the air conditioning system.

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