They were eventually phased out (although thousands are still in service today) because they simply are no longer code compliant in most municipalities across Gordontheplumber.com 24 Hour Plumbing the country. Enter the modern Trip Waste Assembly a simple device which can easily be operated by a flick of a lever located in the bathtubs overflow. Flick it up and the water stops, flick it down and the water drains. Generally trouble free but as time goes by hair, soap scum and variety of mysterious childrens toys make their way into the drain and interfere with plunger causing it to hang up or not operate at all. In addition the linkage that connects the plunger to the trip lever up top gets loose or completely disconnected. When this happens some minor (or major) adjustments will be required by removing the overflow plate / trip lever assembly and exploring exactly what the issue could be. The overflow is also the access through which you would run an electric snake in the event of a complete tub blockage. Care must be taken when performing either of these procedures because not all overflows are secured to the tub thru use of a backup plate which is screwed directly  into the overflow tube. If buy chance that overflow tube becomes dislodged from the waste tee inside the wall, you’ll be placing a call into your local friendly plumber (ouch). This is especially true  when trying to clear a stoppage with an electric snake.

http://www.bobsplumbingvideos.com/in-this-bathtub-drain-stopper-trip-waste-assembly-tutorial-i-demonstrate-how-the-entire-assembly-functions-and-what-to-look-out-for-when-removing-the-overflow-trip-lever-plate/

After all, water supply companies deliver water not only from natural underground reservoirs and springs but also from lakes, rivers... All things considered, it is clear why differences appear. Water hardness usually refers to the presence of calcium and magnesium ions. You can see them easily as fine white deposits on the taps, tiles an especially inside the dark pot in which water was boiling. If you don't remove residues, deposits will build up, which is exactly what happens inside a water heater. There are different measurement units to determine calcium presence in water, but let's consider grain per gallon (gpg), defined as one grain (64.8 mg) of calcium carbonate dissolved in one US gallon of water. Here is a short table which shows different levels of hardness: The tap water in Vancouver is soft (0.3 gpg), in Toronto it is hard (7.5 gpg), but in Calgary and Regina, the water is very hard, 11.7 and 29 respectively. You can find information about water hardness in your municipality on the internet, or from the water supplier. Check out the  map  of hard water in North America.

http://www.hot-water-heaters-reviews.com/how-to-extend-the-life-of-a-water-heater.html

For these heaters to work well, there are some requirements. For example, the fuel supply line must be of an appropriate size. This way, it will provide enough energy to run the large burners needed for heating the water. Another major concern of the gas-fuelled tankless water heaters is the venting. Venting helps in removal of the excess heat emitted by the water heaters. Luckily, they come with vents that can run through the wall or the roof. The vent’s material is stainless steel that is rust resistant and durable. If you are ready to owned and operated incur a little more, go for a unit with a condensing unit. If you decide to get an outdoor tankless water heater, then you do not need to incur the extra cost for venting. This is because the heater will cool by itself.

https://tankless.best/blog/tankless-water-heaters-buying-guide/

You may also be interested to read