Water Heating Systems

Seisco Tankless Heaters

Electric Water Heaters

Inlet Guide Seal Replacement

The inlet guide seal is located on the inlet guide that fits over the upper inlet water tube. It will be necessary to remove the heater from the wall and the control board, in order to replace the seal and the inlet guide itself.

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 guide seal and while installing the new seal.

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 and outgoing water lines threaded onto the top of the inlet and outlet fittings. Use the rag to prevent any water dripping or spraying, which should be very little if any.
6. Back out the AC power wires through the right side of the metal base pan.
7. Remove the entire heater assembly from the wall by removing the 4 mounting screws.
8. Remove the four Phillips head screws in the back of the assembly that hold the heating chamber to the metal base pan.
9. Remove the 2 small screws that hold the inlet guide to the top right of the chamber assembly.
10. Slide the inlet guide up the inlet tube to expose the seal. Be careful not to pull the pipe outward as it may damage the lower inlet port.
11. Note: If it is necessary at this point to remove the inlet guide for replacement, then loosen the 2 screws in the heat sink and remove the inlet tube to separate the inlet guide.
12. Replace the seal and re-assemble in the reverse order
13. Wrap the Teflon tape pipe sealer around the threads of the inlet and outlet fittings before reconnecting the incoming outgoing water lines. 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.
14. Turn on the water and check for leaks.
15. Re-install the control board and turn on the power to the heater. Make sure that all of the circuits are on to power the heater.