Pizza Oven Issue

[Ingersoll AC]

I am working on a couple of year old BLODGETT pizza ovens, first one I fixed no issue. Second one has this issue.

Gas goes from pilot valve assembly down to a safety on/off switch/valve down to a thermostat type valve. This is the one you set your temp. On the good oven if you turn valve to on and the thermostat valve is all the way down it does not light until you set temp. The broken one is at full fire all the time as soon as you turn on. Seems like no control.

My question is this valve has a temp sensing bulb and the t-stat valve. are they seperate pieces or they come as one.

Thanks guys

[Ovenguy]

One piece. It should be a Robertshaw FDTH or FDH (printed on the face of the valve behind the t-stat knob) 300-650 degree throttle body thermostat. You can still buy the gaskets (from aftermarket supply houses) so that you can take off the rear housing of the new thermostat and install it on the existing rear housing eliminating the time and hassle of unpiping the entire valve train.

[EjBreeze]

If you have a bypass screw adjustment on that thermostat check to see if it is set to wide open.

http://www.icca.invensys.com/uniline/e/e38.pdf

[Ingersoll AC]

Ok so this piece of crap is still having issues, I have 6.7"wc input on reg and 4.1" out but then only 2.9" at burner manifold. Blodgett has informed me they can not help till I get it upto 3.5" min at manifold. The stove is tempermental and you have to increase temp slowly or the pilot goes out with main burner. This is a nightmare!

[Ingersoll AC]

If you have a bypass screw adjustment on that thermostat check to see if it is set to wide open.

http://www.icca.invensys.com/uniline/e/e38.pdf

Yes it has two screws one of which has a "B" beside it, thinking this is the by-pass one. Can you explain a little more on your comment please. I think the other screw has a "P" beside it.

Thanks

[EjBreeze]

The "p" is for pilot adjustment which you are not using. "B" is for BYPASS (MINIMUM BURNER FLAME) ADJUSTMENT. Check to see on the side what type of FD valve you have. I have seen some FD valves set up with a minimum temp and no 100% closed position so if the gas was turned on to a cold oven then you would have hi flame until the minimum temp was reached.

FDO Modulating with snap bypass -550°F (288°C) max. setpoint
FDTO Modulating - 550°F (288°C) max. setpoint
FDH Modulating with snap bypass -650°F (343°C) max. setpoint
FDTH Modulating - 650°F (343°C) max. setpoint

Here is a good link for a Marsal oven that should be very similar to the Blodgett. It tells you how to adjust the bypass.

http://www.marsalsons.com/images/505...e%20Manual.pdf

[Navy06]

the tstat is bad on the unit and it only comes in one piece. you should replace it and have the other one rebuilt.