raypak heater wont stay lit

[szub67]

Hi all,
this is my first post here being new and all...
I have a raypak pool heater, milivolt system, model pr265b-mn, it is natural gas 265000btu.
last year i repalced the pressure switch, i just replaced the thermopyle yesterday..
my problem is this, the unit will light and run for about 5 minutes.. I followed the raypak trouble shooting flow chart that came with the manual, i have jumpered all the connections, individually and at the same time, with the same results.. i have a good piolt flame, and the burner flame is a solid blue..
Any ideas what the problem might be? I was leaning to the gas valve, but with all the jumping, the valve seems to operate as it should., also, it is a robert shaw valve if that helps...
thanks for any help!!

 

[Red Neckerson]

Is the thermocouple getting well exposed to the flame? Because it sounds like the millivolts are dropping enough to make the valve "think" the flame isn't there.

 

[szub67]

Is the thermocouple getting well exposed to the flame? Because it sounds like the millivolts are dropping enough to make the valve "think" the flame isn't there.

the thermocouple is in the pilot flame, my volt meter will not read mv, so i need to pick up a new one.. there are several adjustment screws on the robert shaw gas valve, could one be used for turning up the pilot flame?

 

[ps0303]

You shouldn't need to adjust the gas valve. If the flame isn't of the right strength then you would need to replace the pilot assembly. First thing is to get that new meter and check to see how many mili-volts you are getting. You should be reading over 400mv in order for the unit to fire. Ideally you want 500mv. Seeing as you already replaced the thermopile and still have issues, it could be the pilot assembly. The flame has to good and strong, not just blue.