While our customers are wholesalers, Packard knows that you, the contractor, have a choice. You are often presented with many buying options, and being well-informed about your purchase can help make your job easier and more successful. Our Tech Tips are also very helpful for our wholesalers as we present product information that can help as contractors have questions.
This is why we have dedicated a section of our site for contractors and wholesalers. In this section, you will find helpful product tips, tools and some clips from our training classes. We’ve also provided a distributor locator so you can find the nearest wholesaler who can give you access to Packard products.
Static Pressure and the Heat Pump.
We’ve talked a lot about static pressure and its effect on the air conditioning system. What about static pressure impacting the heat pump?
With a heat pump, the equipment manufacturer installs a reversing valve after the compressor. The operation of the compressor remains the same in the cooling and heating modes. But because of the reversing valve, the compressed refrigerant is sent to the indoor coil, which has become the condensing coil. The refrigerant then returns to the compressor from the outdoor coil, which has become the evaporator coil.
Since the indoor coil, now the condensing coil in heating mode, still uses a blower for air distribution through the system, adding static reduces the amount of load on the blower. This results in lower amps on a PSC motor and less air through the system. An EC motor may see higher amps. This less airflow can result in lower performance of the system, that is, not warming the living space as expected. The higher static can result from dirty coils, dirty filters, kinked flex duct, and more, just like in an A/C only system.
We don’t frequently talk about the outdoor coil and static pressure. In the heating mode, and anytime the outdoor unit is operating, it is critical to keep static pressure at a proper level. With a fan blade, increased static adds load to the blade, resulting in more work for the motor. This results in higher motor amps, for both a PSC and EC. The system will not be as effective in removing heat from the ambient air. This means less heat for the living environment.
What can cause an increase in static pressure in the outdoor unit, now the evaporator coil when in the heat mode of a heat pump? The accumulation of leaves around the outside or top of the unit, as well as snow around the coil, can prevent proper airflow. Pine cones and other debris on the top guard of the unit can restrict proper airflow. Applying a blanket or cover over part or all of the heat pump will drastically reduce airflow and heat transfer.
I know it’s cold outside, but for efficient performance of your heat pump you may need to get out there periodically and brush things away from the outdoor unit. Keep the proper airflow around the coil by keeping static pressure at a proper level.
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