Installation and operation instructions document 2100 h0210400- installation and operation instructions for natco fire-coil model 175-400 volume water heaters for your safety: this product must be installed and serviced by a professional service technician, qualified in hot water heater installation...
Table of contents section 1. General information 1a. Introduction ................................................... 1 1b. Warranty ....................................................... 1 1c. Technical assistance .................................... 1 section 2. Installation instructions 2a. Gene...
Natco fire-coil volume water heaters page 1 a 8-1/2 in. (216mm) inlet outlet top view c c optional vent cap for outdoor use drafthood drafthood must be installed in the field header location outlet 40-9/16 in. (1030mm) inlet 5-1/2 in. (140mm) 26-1/2 in. (673mm) side view v 30-3/16 in. (767mm) b sect...
Page 2 hot hot the fire-coil heater is design certified for indoor installation when equipped with a special drafthood, which must be installed without modification. The part number for the drafthood is on the heater rating plate. Follow this procedure to make the conversion: a. Remove the top fille...
Natco fire-coil volume water heaters page 3 c. Remove the vent cap or drafthood from its package. D. Disengage the flue transition ring from the stack extension and place it on top of the collector assembly as shown in figure 4. E. Slide the adapter plate over the bottom of the stack extension as sh...
Page 4 figure 11. Standard base for combustible floor. Figure 13. Typical roof mounting with standard combustible mount base. Figure 12. Typical roof mounting. Figure 10. Outdoor location installation. Figure 9. Incorrect outdoor installation. Window or grill indoor room 4 ft. (1.2m) 4 ft. (1.2m) 4 ...
Natco fire-coil volume water heaters page 5 2d-1. Outdoor air supply when combustion air comes directly through an outside wall, each opening must have a minimum free area of at least one square inch for each 4,000 btu/h input of the total input rating of all appliances in the enclosed area. (in can...
Page 6 warning in cold weather, uninsulated outside vents can chill the rising flue products, blocking the natural draft action of the venting system. This can create a health hazard by spilling flue products into the heater room. Avoid oversize vent piping or extremely long runs of the pipe which m...
Natco fire-coil volume water heaters page 7 figure 16. Sensory bulb locations. Figure 17. Retaining clip removal. Rear tile cover flow switch conduit gap closure grommet drain valve metal channel (for capillary tube) terminal strip heat exchanger assembly gap closure drain plug drain valve rear tile...
Page 8 25. Feed the two brown wires through the top hole on the left side until the conduit elbow is against the jacket. 26. Fasten the conduit by sliding the retaining nut over the two brown wires (inside the control compartment) then screwing it down finger-tight on the conduit elbow. 27. Straight...
Natco fire-coil volume water heaters page 9 if the heater-to-tank circulation loop does not contain more than 6 elbows or 30 feet (9.1 m) of pipe, the minimum pipe fitting should be 1-1/2 inches (38 mm). If the loop does contain more than 6 elbows or 30 feet (9.1 m) of pipe, the minimum size should ...
Page 10 heat flow pressure* water temp exch. Water rate drop rise model passes category gpm l/s ft. M ° f ° c 175 2 soft 22 1.4 5.8 1.8 13 7 normal 34 2.1 11.2 3.4 8 4 hard 46 2.9 19.1 5.8 6 3 4 soft 11 0.7 4.9 1.5 25 14 normal 17 1.1 9.3 2.8 16 9 hard 23 1.5 15.9 4.8 12 7 250 2 soft 22 1.4 5.8 1.8 ...
Natco fire-coil volume water heaters page 11 hot water return from building throttling valve check valve bldg. Loop circ. Pump hot water to building cold water optional cold water supply when adequate tank opening not available to drain heater service valve pump to drain conventional tank figure 21....
Page 12 8. Fill the bearing assembly to the lower level of the overflow vent. 9. Add 5 or 6 drops of oil to the front and rear of the motor. Use 20w non-detergent oil. 2f-10. Storage tank installation 1. Be sure the floor is structurally capable of supporting the tank when it is filled with water, a...
Natco fire-coil volume water heaters page 13 5. Install a sediment trap (drip leg) ahead of the gas controls (see figure 23 ). Fit the trap with a threaded cap which can be removed for cleaning. 6. Install a manual gas shutoff valve for service and safety. Check the local codes. 7. Disconnect the he...
Page 14 11. Before operating the heater, test the complete gas supply system and all connections for leaks using a soap solution. Caution since some leak test solutions (including soap and water) may cause corrosion or stress cracking, rinse the piping with water after testing. 2g-2. Special precaut...
Natco fire-coil volume water heaters page 15 section 3. Operating instructions 3a. Normal operating sequence note: safe lighting and other performance criteria were met with the gas manifold and control assembly installed on the heater during tests specified in ansi z21.13. Warnings vent pipes, draf...
Page 16 figure 25. Typical example of wiring schematic, system 1. Ignition system no. 1 - standing pilot on/off or mechanical modulation volume water heaters (325-400) version b natural or propane gas pump included on pw models, field supplied on vw models.
Natco fire-coil volume water heaters page 17 figure 26. Typical example of wiring schematic, system 12. Ignition system no. 12 - electronic ignition on/off or mechanical modulation volume water heaters (325-400) version b natural or propane gas pump included on pw models, field supplied on vw models.
Page 18 3e. Hi-limit switch checkout after running the heater for a long enough period, bring the water temperature within the range of the hi-limit switch and slowly back off the high limit setting until the heater shuts off. The main burners should reignite when the hi-limit switch is reset and tu...
Natco fire-coil volume water heaters page 19 electronic pilot standing pilot figure 28. Flame patterns. 4b. Replacement of gas controls the gas and electric controls installed on the heaters are designed for both dependable operation and long life. Safe operation of the heater depends on their prope...
Page 20 6. Remove the two screws that fastens the anti- rotation bracket on the left side of the gas valve (see figure 29). 7. Remove the pilot gas tube and copper thermocouple shield, if present, from the gas valve. Caution label all wires prior to disconnection. Wiring errors can cause improper an...
Natco fire-coil volume water heaters page 21 4c-2. Cleaning the heat exchanger an inspection and cleaning of the complete heat exchanger can only be done by removing it from the heater. 1. To remove the heat exchanger, refer to section 2f-1. Caution black carbon soot buildup on a dirty heat exchange...
Page 22 4. Remove the 1/8 inch npt (3.2 mm) test plug in the shutoff valve and replace it with the 1/8 inch npt (3.2 mm) fitting from the manometer kit. 5. Attach one end of the manometer hose to the fitting on the gas valve and the other end to the manometer. 6. Open gas supply valve to the heater ...
Natco fire-coil volume water heaters page 23 3. Make sure the gas valve is on and there is gas pressure in the line. 4. Check all electrical connections and wiring. Finding a loose connection or a charred wire can save a lot of time and money. 5. Check the fuse inside the black, twist-lock fuse hold...
Page 24 5. Check for leaks of the flue collector, vent pipe, gaskets, and all connections. 6. Check the flue pipe for blockage. 5b-7. Testing the fuse to test the fuse: 1. Clip a lead of the voltmeter to the grounding terminal. 2. Touch the other voltmeter lead to the 24vac terminal on the ignition ...
Natco fire-coil volume water heaters page 25 2. Touch the other voltmeter lead to the red 24v terminal on the ignition control. 3. If the voltmeter reads voltage, the temperature control and the manual reset hi-limit switch are not keeping the heater from firing. 4. Make sure the pilot burner is pos...
Page 26 5b-11. Testing the safety shutoff (for standing pilot) after lighting the heater, test the ignition system safety shutoff. 1. With the main burners firing, turn the gas valve control knob off. 2. Turn power to the heater off. 3. Set the temperature control to its lowest setting. 4. Wait 5 mi...
Natco fire-coil volume water heaters page 27 thermocouple thermocouple adapter gas valve millivolt meter pilot figure 40. Testing the pilot thermocouple. 5b-17. Heater will not shut off 1. If the heater stays on with the brown wire on the gas valve disconnected, replace the gas valve (see section 4b...
Page 28 section 6. Parts list for vw and pw heaters 6a. General information to order or purchase parts for the natco fire- coil volume water heaters, contact your nearest natco wholesaler. If they cannot supply you with what you need, contact customer service, natco (see back cover for address, tele...
Natco fire-coil volume water heaters page 29 item description part number 60. Tee bronze .................................................... P0075600 cast iron ................................................. P0071700 61. Bushing, brass ....................................... P0018500 62. Bracket,...
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