Blodgett oven pressure switch

[rclaoac]

One of my customers has a Blodgett oven that would not fire. I found the pressure differential switch was not made. I've worked on other Blodgetts, but have not seen one with a pressure switch. The rubber tubes going to the ports behind the oven were cracked and came off. I cut the tubes back a bit and pushed them onto the ports and secured them with zip ties. The customer calls 2 days later and said they cracked and came off again. What could be causing this? The convection fan works and pushes plenty of air.

[fireye03]

try replacing the whole tube.
i've seen pnuematic panels for hvac controls doing the same thing you cut them back and they crack again.haven't had a problem since replacing all the tubes in the panel.i guess the rubber gets brittle over time.

[rclaoac]

Yeah I'll try doing that. I was surprised at how quickly it cracked though. I cut it back a couple of inches so the tube slipping over the barb type fitting was in pretty good condition, pliable and not brittle at all.

try replacing the whole tube.
i've seen pnuematic panels for hvac controls doing the same thing you cut them back and they crack again.haven't had a problem since replacing all the tubes in the panel.i guess the rubber gets brittle over time.

[deejer28]

might have a hole in diaphragm in pressure switch allowing hot air to feed through constantly thereby overheating... ive never seen a pressure switch on an oven before myself... just a thought maybe could help you

[rclaoac]

I cut the rubber tubes back some more, about 12" and connected to 1/4" aluminum tubing and compression fittings to the ports. The repair has held up, I guess the rubber tubes were in worse condition than I thought. There is little or no heat going to the ports.