Water Heating Systems

Seisco Tankless Heaters

Electric Water Heaters

Inlet Water Fitting Replacement

The threaded inlet water fitting (or nipple) is located vertically on the right side of the heating chamber. It is attached to the heat sink, the inlet guide and lower inlet guide. It will be necessary to remove the control board.

Required Tools:

• Large & small Phillips screw drivers
• battery powered volt meter
• rag, bucket
• two pipe wrenches
• needle nose pliers
• heat sink compound
• Teflon tape pipe sealer.

Warning: To avoid electrical shock, make sure that all of the power is off to the heater before attempting to remove the old inlet fitting and while installing the new inlet fitting.

1. Turn off all the power to the heater. Confirm the power is off with a voltmeter, even if the status light (or LED) on the control board is off. There may be multiple breakers powering your model heater.
2. Open a hot water faucet nearby. While the water is running, turn off the water supply to the heater. This will help siphon some of the water out of the heater.
3. Using a large Phillips screw driver, remove the six screws from the right bottom clean out plate on the under side of the heating chamber to drain the remaining water from the heater into a bucket. Replace the plate after draining.
4. Remove the control board according to procedure A. Changing The Control Board.
5. Using two pipe wrenches, disconnect the incoming water line threaded onto the top of the inlet fitting. Use the rag to prevent any water dripping or spraying, which should be very little if any.
6. Rotate the heat sink by hand far enough to the right and left to allow access and loosening of the two set-screws using a small Phillips screw driver. Use the holes through the right side of the metal frame to reach the set-screws with the screw driver. It is not necessary to remove the set-screws. Only back them out approximately 3/16 of an inch.
7. Pull the inlet fitting tube straight up and out.
8. Insert the new inlet tube, with o-rings in place, down through the guide and carefully press it into the heat sink. Some rotating of the inlet tube may be necessary as it is guided down.
9. After seating the inlet tube, tighten the set-screws. The tube should be free to rotate after turning the set-screws into the grooves. Do not over tighten the set-screws.
10. Wrap the Teflon tape pipe sealer around the threads of the inlet fitting and reconnect the incoming water line. Do not use Plumber’s Putty or Pipe Dope on the threads of the inlet and outlet fitting connections. If using CPVC or PVC primer and glue, avoid contact of these substances with the heater’s inlet and outlet fittings. These substances are highly corrosive and can damage the inlet and outlet fittings. Leaks may occur as a result and cause severe damage to the heater.
11. Turn on the water and check for leaks.
12. Re-install the control board and turn on the power to the heater.

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