Just acquired dayton heater I know where hot leads connect where do neutral and ground connect

Sounds like it's the on/off switch.
what colour are they. . Usually one is the power supply to the switch and the other will be the return from the switch to the load.

Check these wires with with a multi meter.

Ledio, I am unable to access specific photos on Picassa
https://plus.google.com/106982528064073343888/posts

I have downloaded instruction manual for 1755 rocker switch
This is ordinary triple-rocker-switch to control 3 different loads.
It is like having 3 single pole switches and each switch controls a separate light (Load)
This is single pole switch for 120Volt, and not suited necessarily for 240Volt loads.
Switch is not for 3-way application as typically found in hallway where 2 switches control same light.

1) You have 4 wires.
Electricians don't guess, they test.
There are 4 types of wires in 120Volt and 240V household wiring: Hot wire, Neutral wire, Load wire, and ground wire.
Load wire means the wire that connects to switch and goes to Light, fan, motor (load)
Hot wire always connects to one side of switch.
Neutral never connects to switch.
Load wires connect to side of switch opposite Hot wire.
Bare copper ground wire connects to any green ground screw.

2) One-and-only-one wire in each 120Volt electrical box is Hot. (assuming you are not replacing
3-way switch or working with 240V)

3) Separate all 4 wires for testing. Tape tester leads to wood sticks. Turn power ON.
Test each wire to bare ground wire. Tester will light up on Hot wire.

4) Hot is identified. Next, find the neutral wire if it is among the 4 wires.
Test Hot wire to all other wires in box, except bare ground wire.
Tester will light up on neutral wire.
Tester will not light up on Load wires.

5) NOT EVERY switch box has a neutral. Or the neutral wires can be twisted together and covered with wire nut and pushed to back of box.
The neutral may be up in the light fixture. Neutral located in ceiling box is typical with bathroom fan-light-heater combos.
If neutral is not one of the 4 wires, then don't worry about the neutral connection because it will already be wired together.

6) Image of 1755 switch shows 1 screw terminal on the Hot side, so connect Hot wire to this single screw.
Other side of switch has 3 screws for connecting each of 3 Load wires.
Note: Neutral wire is NEVER connected to a switch.
http://www.frostelectric.com/WOE-IMAGES/00381764.jpg

7) Since I cannot see wiring project or know what loads or how the testing comes out, I suggest connect the Hot wire to single screw terminal.
And then connect 1 of the other wires to other side of switch. Not a neutral.
Turn power ON, and try switch.
Process of elimination might yield result.

8) Add a comment with more question, and it sends e-mail. I will respond.
More resources:
http://waterheatertimer.org/See-inside-main-breaker-box.html
http://waterheatertimer.org/B220C.html
http://waterheatertimer.org/How-to-wire-Cooper-277-pilot-light-switch.html
http://waterheatertimer.org/images/How-to-wire-double-rocker-s.jpg

The power cord has a green ground wire; two hot wires, which are black and red; and a white neutral wire. Attach the neutral to the middle connector and the two hot wires to either end of the terminal.
In order to safely ground the machine the green ground wire must be securely connected to the dryer frame. There may be a screw on the frame where you can attach the ground

The switch that you have works like 3 seperate switches. most of these switches will have gold screws
on one side and silver screws on the other side, lets say that the left is gold and the right is silver, and
the switch may also have a green screw for ground. your 12/2 with ground is your main hot, you may
want to mark it with a piece of tape, so you know it's the incoming hot. the ground off your hot will tie,
to the green screw on switch and continue and tie to your vent light which should also have a ground
the white coming off the hot is your neutral, it will go straight to your white or whites on your heater.
the black hot wire at your switch will go to each gold terminal on one side of the switch,there are two
ways you can do this, go to one side and just run a jumper, or put one wire on each gold screw and
tie in to your hot-black wire with a wire nut. now for the switch legs, you will need to run from your, switch
to your heater either another pair of 12/2s or a 12/3, each side of the switch that has one silver screw,
it's easier with a 12/3 normally a 12/3 will have a red,black,white,and ground.
top switch red to red on heater,black to black on light and the white blue on the vent,so from your switch
to the heater you would have to run a12/2 you would not use the black only the white and ground.
remember the white-neutral coming from the switch will be tied to all the whites at the vent,light,heater
except for the 10/3. the 10/3 is used stricktly for the switch legs. good luck!

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Look at the diagram here. It is actually called the neutral wire with a hot lead on each side. The new 4 wire dryer cords actually have a ground and a neutral. The neutral and the ground are usually hooked together or "bonded" in a breaker box. Heater draws 21 amps so you should be good to go.

Look at the name plate on the motor. If it's 'duel voltage' it will show a 'high' and 'low' voltage hook up. If it only shows one hook up config, then use the rated voltage on the name plate. If 240 volts, use L1 and L2 for incoming power @ 240volts.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/craig_3fa289bf857b1a3c

What were you wiring? Usually the white wire is a neutral which is connected to a white wire or your neutral bar in the panel.

sounds like you either "crossed-phases", connected a red and black wire together somewhere or you have a "ground fault", a hot wire is somehow contacting something connected to ground or neutral.

would you write me back and let me know what you were installing and what you did other than what you wrote here so far.

The white is the common neutral, it is probably a 3 wire unit, and you are missing the ground wire. Check inside the control panel and see if someone wired it using the white wire for the ground, it will be screwed into a terminal lug. Check the schematics to see if the unit requires a common neutral to run the controls.

I have a fahrenheat F2548 baseboard heater, there were not any wiriing diagrams or installation instructions in the box where can I find the wiring diagram,

If that is a 240V unit then you are correct wiring L1 and L2 to black and red. Unless the unit uses 120V for something like a control panel, it doesn't need the neutral.