pilot not staying on!!

[novascotia]

hello to all, im new to this and have a problem.
when i light my pilot it stays alight. then when release the button it goes out and will not stay on. while ever the button is depressed the pilot stays alight no problem at all.

 

[CH4]

The pilot light heats up a thermocouple. The thermocouple generates an electromotive force (e.m.f.). The e.m.f. passes through a small coil (within the gas valve) to form an electromagnet. The electromagnet holds the gas valve open when the button is released.

So, the thermocouple may have failed, it may not be getting sufficient heat from the pilot light (because it's not fully in the flame or the flame is too small) or the coil may have failed.

Thermocouple failure is the most likely cause of your problem. Since a replacement thermocouple is cheap, it's worth changing it first.