Regular and preventative maintenance on heating and cooling systems is an important factor that cannot be overlooked if you want a stay cool in the summer and warm in the winter. A good water treatment program for the closed loop heating and cooling systems in your building is as important as keeping pumps and fans running. Poor water chemistry in your closed loop systems can lead to fouling or plugging of the coils and heat exchangers. This fouling may increase your pumping cost and has a significant effect on the ability of your heat exchangers to deliver the temperatures and relative humidity that you and your tenants need to stay comfortable. Fouling also decreases the overall capacity of your heat exchangers and reduces your loop temperature difference, which can lead to an increase in the Thermal Inefficiency Fuel Surcharge on your DES invoice or tenant complaints.
Plate and frame and shell and tube heat exchangers need to be regularly inspected and should be back-washed at least annually. These heat exchangers should be cleaned every three to five years thoroughly or sooner if problems are noticed, so that they can operate at their best. A good water chemistry program implemented and maintained by a reputable water treatment contractor is an excellent first step in reducing the effects of fouling and corrosion in your in-building system.
Let’s not forget to clean the air-side of your air handler and fan coil units, too, and to maintain clean air filters. Air-side fouling at your coils can also decrease the capacity of the units and can contribute to lower approach temperatures, a decrease in dehumidification and an increase in fan horsepower. Dirty and contaminated coils and air ducts can become breeding grounds for molds, mildew and other organisms that can be harmful to your health.
Below are a couple of links to operating and maintenance manuals for plate and frame and shell and tube heat exchangers. They contain some useful information on cleaning your units and preventative maintenance. We recommend that you contact the manufacturer or supplier of your heat exchangers to obtain their latest manuals, but you can use these links if you do not have manuals on your own equipment.
Installation, Operation, & Maintenance Instructions for JFD Shell & Tube Heat Exchangers
PFX Plate and Frame Heat Exchanger
This last link is a white paper on water treatment that you may find useful.