I am replacing a thermostat and the 1 being replaced has 4 wires on it but the new thermostat only has 2... do I connect the whites together and run the 2 blacks from the thermostat to complete the circuit?

I am replacing a thermostat and the 1 being replaced has 4 wires on it but the new thermostat only has 2... do I connect the whites together and run the 2 blacks from the thermostat to complete the circuit?
Without more details on the thermostats it is difficult to say.
It seems to me that the one you want to install is a either a simple (mercury or spring) model, or a digital one.
The digital thermostate may be polarisation sensitive, so be careful.
As to the wires to be used : it depends on what type the old thermostate is, and where it is using these 4 wires for...
;)

The box which houses the thermostat has 2 lines running into it,
1 from the electrical panel and 1 to the heater.
The thermostat being removed is a spring type and has the 2 blacks on one side and the 2 whites connected to the other side of it... the thermostat being installed is a spring type and has the 2 wires out the back of it.
For previous heaters I have installed I completed the circuit by connecting the blacks to the thermostat and joined the whites together. I hope this explains it a little better

artosie, sounds like your method should work.

Great! I am going to try it in an hour... I will reply here and let you know if it worked..

Thanks again

Do you have both heat and AC in your home? I think you bought the wrong stat if your old one had 4 wires. This may help but please answermy question. https://www.askmehelpdesk.com/heating-air-conditioning/heating-cooling-maintenance-repair-troubleshooting-frequently-asked-questions-58313.html#post268211

Ballenger, I was thinking the same thing, but since he said 2 in and 2 out, Not 4 in, was thinking more Line in and load out. I'm thinking this is #12 or bigger, not Control wires.
Curious if he has Heat and Cooling, and size of the wires. Take Care