Hot box

[kmjt1021]

I have a Hydrotech hot box, that will burn for a few minutes, then stop burning. If you shut it down for a few minutes it will then fire back up but only for a few minutes. I know You probably need more info, I just don't have it here now. let me know what info is needed and I will get it.
PS. I did replace the flow switch, didn't help

 

[Russ Johnson]

Check the fuel filter. If it's stopped up, it will burn for a short time, then go out. Does it have the Racor Oil / Water Seperator on it? That is an excellent filter but will stop up completely if not regularly serviced.

 

[Hotwaterwizard]

Fuel problem is correct. If the fan motor is still turning. Check the temp control knob and see if it is up all the way. Vibration will cause the knob to turn by it's self. If that is what is happening take off the knob and put some small O-rings on the shaft and put the knob back on against the O-rings this will make it hard to turn or vibrate closed.
HydroTek units have the plastic tank and you need to make sure the fuel level is higher than the suction hose barb in the tank.
Fuel filter is the first step. Fuel hoses and clamps are second. If all fails look at the fuel nozzle and fuel pump.