Water Coil Installation Recommendations


1. Piping should be in accordance with accepted industry standards. Always use a backup wrench on the coil connections when attaching the piping to the coil if pipe thread connections are utilized.


2. When drainable coils are desired, tubes should be installed in a horizontal position. Use a spirit level.
If the tubes cannot be installed level, special drain headers are available on request.


3. Connect the water supply to the bottom connection on the air leaving side and the water return to the top connection on the air entering side.


4. When four connections are provided the extra bottom connection can be used for an auxiliary manual drain connection, and the extra top connection can be used for an automatic air vent or the extra connections can be capped. Connecting the supply and/or return in any other manner will result in very poor performance.


5. Water coils are not normally recommended for use with entering air temperatures below 40°F. Glycol solutions or brines are the only freeze-safe media for operation of water coils for low entering air conditions.


6. When fresh and return air are to be heated or cooled by a water coil, care should be used in the design of the ductwork to insure thorough mixing before the air enters the coil. The return air should always enter the bottom of the duct. Fresh air should enter the top of the duct. The greater the distance between the points of mixing and entrance to the coil, the better the application.


7. Two position control valves, modulating valves, three way valves or a combination of these controls can accomplish control of water coils. Follow the recommendations of the control manufacturer regarding types, sizing and locations. Face and bypass dampers may also be used, but do not close off tightly. Air leakage in cooling applications has no appreciable effect. In heating applications, however, the air temperature may rise several degrees and should be considered in system design. Low leakage dampers may be required.


8. Pipe sizes for the system must be selected on the basis of the head [pressure] available from the circulating pump. It is recommended that the velocity should not generally exceed 8 feet per second and that the friction loss should be approximately 3 feet per 100 feet of pipe.


9. When cooling coils are banked two or three high, an intermediate drain pan with plastic drain tubes extending into the main drain pan should be installed on the air leaving side of each coil. On high latent installations, the condensate draining from top coils may load the lower coils with condensate, resulting in reduced air flow and performance or condensate being blown downstream into the ductwork. All individually installed water cooling coils and the bottom of all cooling coil banks should be mounted in drain pans extending at least ten inches from the leaving air edge of the coil. A drain line trap must be installed to allow condensate to drain freely. The drain line trap depth must be twice the negative static pressure of the operating system for the unit to drain correctly. Incorrect trapping can cause the drain pan to overflow.


Note: Vent and Drain connections are provided on Surefin Coils water coils unless otherwise specified. This allows the coils to be drained. Keep in mind that when draining the coils, all water may not drain from the coil. In order to completely drain the coil to prevent the possibility of freezing during cold ambient temperatures, air or nitrogen pressure must be utilized to blow any remaining water from the coil.

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