How remove a pilot generator from a minimax ch 200m

Simple:

• Insecure bracket holding the pilot assembly to the burner tray
• now, remove the pilot assembly from bracketry
• unscrew old pilot generator/thermo pile or thermocouple
• new may have a clip instead of threaded nut
  • diameter of hole is same so it should just snap into place
• in reverse order resecure the pilot bracket to burner tray

bad heat exchanger or you have condensation this happens when the temperature delta is too high

You probably need to change out the pilot generator. That is what tells the gas valve that the pilot is lit. They wear out after a few years.
It's not a tough DIY but you may have to pull the burner tray which involves opening the gas line. A pool tech should be able to change it out for about $130.

ok is millivolt heater need to check all the safety circuit are getting power ,also check for clean filter ? is the water pressure switch inside the heater is closed ? did u check if the pilot generator is generating more the 600MV ? also check for any loose wire connection ,a 9 volt battery generated more voltage that u pilot generator

check the vent to the outside air for an obstruction

millivolt heaters generate their own power from the flame on the pilot max is usualy 750 millivolt, check all connections clean and secure.
Mmake sure the pilot is lit

There should be instructions on the inside of the heater access door. Make sure you are comfortable working with gas heaters. Make sure the shutoff valve supplying gas to the heater is on. Turn the gas valve to "pilot", press and hold it while attempting to light the pilot. Once the pilot is lit, continue holding the gas valve knob down for about 30 seconds. The pilot should stay lit once you release the knob. If the pilot stay lit, turn the gas valve to "on". Replace the heater access door and make sure you have proper water flow and attempt to light the heater. If it will not light, or the pilot will not stay on, you will probably have to replace the pilot generator. It provides voltage to run the heater and after time it wears out and produces less and less voltage. A millivolt heater runs on less than one volt so any power loss can be a problem. If you are able, test the pilot generator with a multimeter to see if you are getting at least 500mv when the pilot is on. If not, you should replace the pilot generator or even the entire pilot assembly. Hope this helps...