Trouble Shooting Diedrich ignition, a documentation of a support call

Below is a log of the support call to Diedrich to troubleshoot an IR12 roaster not igniting.

The Support People asked a question then we replied:

Q

Let’s test the Dungs vacuum sensor. If you remove the clear cover, you can turn the dial and change its sensitivity. Mark where it currently sits before you move the dial. It should be set at 0.3 but try moving it to 0.2 or 0.1 and seeing if your roaster will light. If it does, that will tell us that you have an airflow restriction somewhere in your roaster. If not, we may need to replace the vacuum sensor. The little plastic/rubber tube that comes off the Dungs valve and connects to the tube that hangs down in your blower housing should also be checked to make sure it’s completely clean. Let me know what happens.

A

We actually connected the 2 brown wires together in the sensor today as the fault finding guide says to do. But I have done as you asked and still nothing. I tried it at 0.1 and 0.08 still no spark

I disconnected the black tube too and I can blow or suck through it fine

Q:

You also checked the aluminum tubing that hangs down in the blower compartment? If you’re sure everything is clean, we can try replacing the vacuum sensor and seeing if that fixes the problem. I’ve attached our guide to narrowing down where the issue may be. Do you already have this guide? (see below) It says if you’re not hearing the clicking, to check to make sure your high limit unit is functioning. We should try to rule out as much as possible before we replace any parts.

A:

This is the one we used, we go through it a few times. This is the guide that says to take the vacuum sensor out of the loop by connecting the 2 brown wires, we did that and it made no difference, so surely it is on the sensor? I checked the tube, blown through it and sucked through it. The roaster is clean we are fussy about this. The automatic machine reset the high limit when you power on the roaster. I am not how else to reset it. I am not sure where the Watlow thing is positioned.( Turns out it is next to the Abbey Electrical Igniter, with jumpers labeled

Q:

With the blower on, take a continuity reading between commonly open and common to make sure we’re getting power there. If yes, then the ignition controller may need to be replaced, if no power, then the vacuum sensor needs to be replaced. Let me know what you find. Check for power at these two connections on your Abbey ignition controller.

A:

Did this and use the wiring diagram to determine the startup was stuck at the vacuum sensors. Looks like shorting out the wires did not help. When we blew into the pipe it then worked. Found a blockage in the outside chimney.