Steve,

I have not been able to find a replacement for the 261 thermostat and have used a 235 housing and thermostat on my 261.

Have you tested your thermostat? This can be easily done in hot water with a thermometer (to tell you at what temperature the thermostat starts to open). http://www.markl.f9.co.uk/howto/electrical/cooling/cooling.htm

Tim