/ Marley Electric Basin Heater / User Manual 92-1322C
/ Receiving and Inspection / The heater package is shipped directly from the vendor. 1. Check all parts for any damage in transit. The carrier is responsible for the condition of the heater package upon arrival. If damage is apparent, note the freight bill accordingly. This will support your claim with the freight carrier. 2. Check the nameplate on the enclosure and verify that the heaters and the control panel are rated for the correct voltage. 3.
/ Introduction / The purpose of a basin heater is to prevent water freezing in the cooling tower basin during periods of shutdown or standby operation. The heater system is sized according to tower model and location to give maximum protection against water freezing in the cold water basin. This heating system is not intended to protect the tower fill and other components from icing. Refer to Marley Technical Bulletin # H-002 "Operating Cooling Towers in Freezing Weather.
/ Installation / Note For detailed information concerning installation, refer to the heater installation drawing provided with the cooling tower. Heater Element Install the heater element(s) in the depressed area of the cold water basin near the outlet. Provide clearance of 7⁄8" or more above the floor. A single centrally located heater can protect up to 300 square feet of basin surface area from ice damage. To protect larger surface areas, position several heaters so they protect equal areas.
/ Installation / Control Panel The control panel is suitable for outdoor mounting, and may be mounted on the tower, but not inside the tower. Wire the heaters to the panel. Wire the panel to the branch circuit supplying power to the heater. The field supplied branch circuit disconnect switch and the branch circuit protective device (fusing or circuit breaker) shall be sized in accordance with the NEC/CEC rules for actual load. The total heater load can be calculated as shown below.
/ Installation / Temperature / Water Level Sensor Assembly Warning This basin heater package is equipped with a combination temperature/liquid level sensor and may have a thermal cutoff switch. Both are safety devices that must not be altered or changed in any manner. Disabling either safety feature may result in combustion and/ or fire, which could cause damage or destroy the tower and may cause damage to persons or property nearby.
/ Operation / Operating Instructions To operate the heater system, visually check that the water level is above the sensor probe before energizing the power supply. The temperature control is preset at 45°F. The system will not energize unless the water level is above the sensor probe and the temperature of the water is below the 45° set point. The solid state relay card located in the control panel has a green and a red LED—see Figure 1.
/ Operation / Testing above Freezing Temperatures Under normal operating conditions the heaters will be turned on at a water temperature between 40° and 45°F, and turned off when the water temperature exceeds 45°F. For testing the system at temperatures above 45°F there are two methods as follows: Method A 1. Disconnect power to the control panel using standard lockout procedure for safety. 2. Remove the panel cover 3. Remove the sensor wires connected to terminals T1 and T2 on the relay circuit board.
/ Operation / Method B 1. Disconnect power to the heater control panel using standard lockout procedures for safety. 2. Drain basin until the water level is below the probe allowing removal of the probe. Make sure water still covers the heater elements. 3. Place the probe in a container of ice water making sure both metal parts of the probe are submerged but not the cord. 4. Energize the heater control panel. Allow 5 min. for the probe temperature to stabilize. 5.
/ Operation / Deicing If the temperature/water level sensor assembly becomes encased in ice the heaters will not operate. Ice provides inadequate conductivity for the sensor probe to detect operational water level. To operate heaters in this situation and melt the ice follow these procedures. 1. Disconnect power to the control panel using standard lockout procedures for safety. 2. Remove the panel cover. 3. Install a jumper wire between relay terminals G1 and G2—see Figure 3.
/ Troubleshooting / Caution Please refer to the Caution statement on Page 6 and the Warning statement on Page 7 of this manual before performing the following Troubleshooting procedures. If the system fails to operate, check the following: 1. Check water temperature. Systems will turn on between 40° and 45°F and turn off above 45°F. 2. Check water level. Water must completely cover the sensor probe. 3. Make sure the sensor is not encased in ice. See Deicing procedure.
/ Troubleshooting / 2. If the contactor does not operate, check voltage across terminal N on the circuit board and NO on the relay mounted on the circuit board —21-29 volt required. If voltage is present across the coil—N to NO— the contactor coil is defective and the contactor must be replaced. If voltage is not present, the circuit board relay is defective and the circuit board must be replaced. C.
/ Parts List / 1 2 24 240 120 N CT COM NC NO 3 RED GREEN SH T1 T2 G1 G2 4 5 Replacement Parts 1 Transformer 120V/24V............................................... B52465D Transformer 208V/24V............................................... A79270D Transformer 240V/24V............................................... B91566D Transformer 480V/24V............................................... B09608D Transformer 600V/24V...............................................
7401 WEST 129 STREET | OVERLAND PARK, KANSAS 66213 UNITED STATES | 913 664 7400 | spxcooling@spx.com | spxcooling.com In the interest of technological progress, all products are subject to design and/or material change without notice. ©2008 SPX Cooling Technologies, Inc.
