Ya u have to go to good service shop which has good technician other wise tis issue creates more issue.

Proceedure to change Thermostat :-


Old thermostats are wired at very low-voltage, so there is very little shock risk. I replaced mine without turning off the power, but I'm not necessarily recommending that to anyone. Flip the breaker to cut the power, to be on the safe side.
The first step is to remove the cover from your old thermostat. It might just pop off, or there might be screws holding it in place. Don't remove the entire unit yet, just the front plate or cover.
Inside your old thermostat, there will be a number of wires, all fastened to points inside the unit and disappearing back into the wall. Each wire will be labelled (either on the wire itself, or at the connection point) with a letter. With labels that come with your new thermostat, or pieces of masking tape, clearly mark each wire.
Disconnect each wire, taking great care not to let them fall back into the wall. The labels are likely large enough to keep them from falling through the hole, but you need to watch them. Wrap them around a pencil, or clip them together with a large binder clip. The last thing you need is to have to fish a skinny little wire back up through that hole.
Once all the wires are disconnected and labelled, then you can remove the rest of the old thermostat unit from the wall. You should now have a hole in your wall, with a number of wires sticking out.
Your new thermostat will have a hole in the back for the wires to come through. Pull the bundle of wires through, and place the unit against the wall. Use a level to make sure it's straight and attach to the wall, using the screws provided. You can also use anchors if you wish, though I have never felt the need to.
Ok, now you have your new unit in place and it's time to reconnect all those wires. Read the instruction manual carefully at this point. Depending on your existing wiring, you will likely only have to match up the wires (G goes to G, and Y goes to Y, for example). But your manual will explain how to arrange the wires if the letters are not the same. Most configurations can be adjusted for.
Put new batteries in your thermostat, and put the front cover in place. Your thermostat should be up and running at this point. You will need to follow the manufacturer's directions to learn how to program the unit.



Thnx.

U can get the required part for your machine at------- repair clinic web sites------------.just select the proper model number and company name in the parts  search column.and the list of all the parts will be displayed.order the required parts online they will provide u the best service to send you the part.

Dear Sir/madam, Auto select of main burner: Press burner button, the flame is on ?AUTO? select. Press button to set temperature. If the room temperature is two degree lower than the set temperature on the remote, the main burner will turn on until the surrounding temperature is two degree higher than the set temperature. Once it reaches temperature on the remoter, the main burner will automatically Shut Off. Thanks Good luck

Check the control selector for any damaged and if its working properly.

the thermostat selector or the heating element is not functioning properly, or a defective part was causing the unit to shut down.

Look it has the thermostat issue