Are you running 110 or 220?
First - wait. The tub will heat at about three degrees an hour on 110v, and about ten degrees an hour on 220. It will start out much slower, and only hit those 'speeds' as it gets closer to the 100 degree mark.
SO OFTEN I get calls saying the new spa I dropped off an hour ago isn't hot, what's wrong - so let's get than one out of the way first.
Next - the tubing should NOT feel hot. Maybe just warm, or
slightly warmer on the outlet than the input, but not hot. Not if the water is still at tap temperatures. Later, when the tub is up to the 100 degree range, you can feel heat coming from the floor fitting, and the inlet/outlet tubes may feel different to the touch. Use an amp meter on one of the wires going to the heater. Twelve amps (wide range, but this neighborhood) for a 110 and twenty three amps for a 220. If not, then you have something wrong - the heater may have tripped the high limit. If your heater is the new PDR type, you simply have to shut if off, let it cool below 90 (may be there already if the water is still tap temperatures) and then turn the power back on.
Finally - check the voltage ACROSS the two outlets to be sure you have 220 going to the heater - if the tub is wired for 220. Crossed wiring will often show up in new installs: you only said you have 118 coming from each of the leads to the heater, you did NOT say you have 220, measured between them.
Keep us posted -
HTH