Tankless Water Heater Install Diary. The following information was sent to us by a satisfied customer.
Here is where the old tank lived. Notice the rust on the floor, water lines and old gas line. The regular old gas tank finally leaked. Tanks can collect sediment in the bottom and rust out. There was a small pinhole leak that caused the pilot to be extinguished. The tell tale sign is cold water, where the hot water should be.
Locating the tankless water heater
These pictures show the old power vent exhaust for the tank. I needed to decide where to hang the tankless water heater. In this case the decision was easy. The gas. Water and venting were all on an outside wall, ready for the new tankless water heater. I checked the manuals for the distance to separate the exhaust and air intake. The new Exhaust could be 3 feet apart at a minimum. This allowed the old exhaust to be the new air intake, leaving only one hole to be cut.
Measuring vent clearances
Here is the outside location of the old exhaust (not to code). I will need to run the vent out to the proper distance to meet the edge of the building. All clearances were checked in the manufacturers manual.
Measuring for the wall thimble hole
Be sure to reference the same point inside and outside BEFORE cutting the new vent hole. Trace where the hole will be cut on BOTH sides. It takes some time to run outside and come back in, but it's important.
Cutting the wall thimble hole
Always wear safety equipment. Safety glasses and protective gloves are a must! A saws all works well for most homes. Take your time and be sure to test fit the wall thimble or terminator. DO NOT screw the thimble into place at this point. You will want to wait until the exhaust venting has been installed and the angle of the venting has been checked.
Placing the wall thimble/terminator
This is where a second set of hands is helpful. Test fit the thimble BEFORE placing it into the wall. Check to see how well it pulls apart and goes together. The thimble might need slight adjustment. Be careful not to destroy the thimble, as tack welds can be pulled apart by rough handling.
Insert the thimble from the inside and have your helper place the outside piece. Once in place, insert your straight venting into the thimble. In this case the thimble face needed to be cut on the bottom, with tin snips.
Fresh air intake
Here is the fresh air intake. This was run with flexible 3-inch intake pipe. The vent was placed under an overhang, where snow would not accumulate. This should be checked every time you need to shovel.
The exhaust vent was placed away from the intake to avoid cross contamination and meet the national gas code. The exhaust is well above the ground to prevent snow from covering the terminator.
Hanging the backer board
There are many ways to hang or mount a tankless water heater. I tied 2x4’s into the joists. Note the C-clamp being used here. I used the clamp in the same manner to clamp the 2x4 to the joist, while screwing it in place. This holds the work and prevents the wood from moving, while being mounted. Make sure you check the mounting locations on the tankless water heater.
Locating the height of the backer board
Once the through wall pipe is installed into the thimble, hang the 90 degree elbow and back draft preventer (if required). This will give you the approximate height where the tankless water heater needs to be.
Mounting the backer board
Measure and cut the backer board, checking the dimensions and clearances of the unit. Mount the board and make sure it is stable and able to support the tankless water heater. The backer board should also have room for mounting any additional hardware. Items to consider are shutoffs, drains, gas connections and wiring.
Prepping the tankless heater for mounting
Any accessories or wiring can be done before the tankless heater is mounted. It is much easier to do this type of work on a bench, before the unit is on the wall. Here the TK-Jr's direct vent kit (TV-09) is being installed. This requires a small faceplate to be removed from the top. A fresh air intake will be put in its place.
A view of the installed TV-09
Note the faceplate on the front of the TK-JR. This covers the open louvers, completing the direct vent kit.
An electrician should do any wiring. Only if you are comfortable and understand wiring should you do this your self. Note the screw clamp on the small electric box. This was not provided. It prevents the wire from being pulled out of the tankless heater.
Electrical wiring continued...
Here is the 120v connection complete on the TK-JR.
Hanging the tankless water heater
Once the tankless water heater is prepped, we can hang the unit. The TK-JR has easy mounting brackets attached the chassis. This is a two-person job. One person hangs the heater to meet the venting and the other screws the unit into the backer board. Follow all of the instructions for attaching the venting.
Mounting the fresh air intake pipe
Here the tankless heater has the exhaust attached and the fresh air intake is just to the left. Gear clamps are used to attach the flexible intake pipe.
The water connections are loose at this point and will be mounted to the board, with talon clamps, to stabilize the water connections. You can also see the gas line. A licensed gas technician did this.
TIP! Ask prospective gas people if they have gas test equipment. Tankless Water heaters need to have proper gas pressure set and tested to get the full performance of the unit. Tankless water heaters typically use larger gas lines than tanks. .
Plumbing the water connections
I choose to use PEX, flexible stainless steel connectors and copper for the water connections. Here is the copper portion, which will sit between the flexible connectors and the PEX. In order the Falcon stainless steel connectors attach to the water heater, then thread into the copper assembly shown, then 3/4inch PEX push fits into shark bite connections. Shark bite unions make the final connection back to the original hot and cold. Always refer to the manufacturers manual for the correct way to mount pressure relief valves, drains and shut offs.
TIP! Having drains and shut offs make draining and cleaning the tankless heater easy. If scaling is a problem in your home, this is something to consider.
Shark bite fittings make PEX to copper connections easy
Shark bite push fittings make this very easy. These fittings accept copper, PVC or PEX. They are very quick and can be disconnected easily. There is no concern about attaching to wet, pitted copper pipes. All of the soldering required for this install was done on a workbench, taking away any concerns about scorching joists, while sweating connections. This technology has been used for fuel lines in automobiles for years. They are solid and safe for all water connections, potable or heating.
Attaching the water connections
Carefully HAND-thread the falcon connections onto the tankless heater. Only use a wrench when you can no longer tighten the nuts by hand. Note the cautions over tightening on the flexible connectors labels. I had already threaded the copper shut off and pressure relief assemblies, before attaching to the heater. Now the PEX is ready to be installed, to complete the water connections.