Connect the wire to the connector. Makesure the wire secure tight with the screw connector. Cost this heater run at high watt when max. Otherwise the connector will heat up and kaboom.

I put an additional silicon to seal the wire intake hole. Cause the heater from the shower head is a bit near. This is to prevent the water from sipping in and kaboom the heater.

Done for the wiring. Now the plumbing side. I have place the elbow to the inlet heater valve. So I can measure the vertical pipe lenght that need to be cut.

Use sand paper to clean every fitting and pipe that need to be glue. This will clean up the oil and dirt. So the glue can melt the pvc pipe securely. Wipe with clean cloth.

Tape the screw fitting with white seal tape.

The vertical pipe is temporary insert in. Now use the elbow to mark the lenght of the pipe to be cut. Glue all together. In this step, you need to act fast. The glue will cure fast. Plan which fitting to go in first and how to fit in together. Than apply the glue.

The plumbing done. Wait for 1/2hr or longer for the glue to harden. It actually need 24hr to be harden. But since the water pressure not that high, 1/2hr should be alright.

Open back the stop cock. Check for any water leakage. Than turn the heater valve to open. Let the water flow out from the shower head. Check any leakage in the heater side joint. This is important to makesure no water leak out internal. Any water leak, disamssembly it and take the heater to claim. Close the valve and put back the heater cover.

Switch ON the heater switch. Than reset the RCD. If the RCD trip, switch OFF and check the wiring.If everything OK, the heater light will ON.

Continue........
This is acrylic sealer right? If before dry can wash away with water is acrylic. Silicon can't wash away with water.