Why You Need A Professional For The Job

In this age of YouTube and DIY solutions, it is fairly simple to find out how to install a water tank or to do your own repairs on one. It might be something to consider if you want to save yourself some money but this one area where taking care of the pennies might backfire badly. 
Heating tanks are not appliances that you want to mess with. Having gallons of hot water cascading down from the ceiling is not something that you want to risk. This is not a case when the worst-case scenario is that the appliance doesn’t work if something goes wrong. 
And let’s not even start talking about messing with a gas-powered system or the dangers of the heating element burning out. Step away from the toolbox, and no one will get hurt. Need some more convincing? 
You Will Void the Warranty
These tanks are not cheap. Not having them installed or repaired by a professional will likely void the company’s warranty on the tank itself. Professional plumbers will also guarantee their own work so if there are any problems with the performance; you have recourse. 
Not Up to Code
Do you know what the fire or building codes are regarding these tanks? A professional plumber will and will also be able to get the right permits for plumbing going forward. 
Installation
This is not a plug and play device. Installing it means messing with the electrics and the piping and venting in your home. Do you really want to risk possibly burning the house down so that you could save a buck or two? 
It Is a Specialized Job
Have you ever tried lifting a standard hot water tank by yourself? Even the smallest ones are pretty heavy. Now imagine getting that into place in the ceiling or even up on the wall. It is a difficult job, even when you do have help.
If you are an enthusiastic DIYer, you might find that you have most of the tools that you need for connecting the wiring, etc. But if not, you are going to have to get them, and that is even more of an expense. It all adds up pretty quickly. 
Your Insurance Could Be Voided
Say that something does go wrong. What if the tank bursts or the wiring causes a fire? If the cause is narrowed down to the tank, your insurance company could request proof that it was professionally installed.
If they get wind of it being a DIY job, they would be well within their rights to refuse to pay any claims. 
It is Not Safe
We have already gone through this one. If you make a mistake when installing this, the potential for injury is high. Even something as simple as swapping two wires accidentally could lead to things going wrong really quickly. It really is not worth the risk.
If you are that keen on DIY, start with something simpler and leave this one up to the experts. No matter how many YouTube videos tell you how easy it is to replace an element, or install your own on-demand hot water heater system, this is something that is best left to a pro.