Then whatever you like. For sealing gas connection, even two, in my case, from the heater, I used the tape FUM. Gathering information on the web, found the view that the connection to spin, sealed tape FCMs can not, because they will lose their tightness. I do not know whether it was true but did not check, to wind the tape to the connection tight and tight scrolls, and so it spun through. On the other hand fastened to the pipe aligned with paranitovoy butt pads. Important not to win, but then I first gasket tightened too much, and then are surprised that the gas passes. When unscrewed were two - internal and external, tube cut. After assembling all the connections, open the gas valve and always check the tightness of all of our new compounds with something good foaming , such as a solution of liquid to wash dishes. Patiently waiting to find even the smallest gas leaks, if any. Found the leak - close the gas tap, spin and rework sealing, and so on to complete elimination.
He took off the lid of the heater:
I used a hose to the cold water that was in the set, he had to take a further clutch:
Was such a design after assembly and connect all hoses:
Water connections plumping linen with a special paste plumbing too well turned out. Turn on water and check for water leaks. Here, too, as you like, if you suddenly drop to somewhere and it will not confuse you, then let the drips, it is safe, if the water does not fall on the floor. Even the neighbors do not flood the bottom, or rather not spoil.
Gas connection beside the crane covered from the spray "paint with zinc ions, which prevents rust":
Since the new size of the previous heater, the chimney should be bit of a stretch, since he of the corrugations and easily stretches and takes the desired size. It remains to adjust the heater. In this case, you need to unscrew the screw of adjustment of maximum gas supply to at least some gas supply began.
Immediately sunk into the heater did not want to light up, I long snapped, then almost did not catch it all, but I think you just have to press and hold the button ignition for the gas to fill the interior space and went to the fuse. Remains include hot water and enjoy the burner inside the softly lit and warm water.