fixbear
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Was this oven just installed or relocated? Rational ovens have a power switch that provides power to the control transformer's. If the power taps are not checked and verified at commissioning, You may burn one out. Especially the toroidal one. They are made for the world market and all the different power grids.
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That cord is a mounted plug with 2 taps. All the years of working on True coolers I've never had to replace one. And it's been used on all 115V models for many years. Everything from 49 cu ft reach-in's to prep tables and under-counters.
Two mounting screws, two spade connectors, a ground wire, and two line hard wires. The spades are in series with the temp control for the compressor plug. The hard wires are power for the evaporator and cabinet lights.
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The Motor wiring is on the cover of the new motor. If the old one had separate mounted capacitors, You can just remove them. Check the wiring diagram attached to the oven. Tito may be able to get one from Blodgett for your conversion. But there should have been paperwork with the motor for it. I don't know enough of your oven as they used multiple control systems and single, two, and three speed motors.
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Yes, the pilot is adjustable. From the top of the valve (red button) there is a small cap screw at about 11:00 “O'clock. Remove the cap and you will find a slotted screw under it that is a needle valve for the pilot
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Several different possibilities here. Is this the original controller or a replacement? If a replacement, what positions did you place the jumpers? What did you set as a dwell/differential? Hopefully it hasn't had the wiring for the defrost heater miss-wired or cross wired with the compressor.
The PTC (thermistor) can be tested with a ohm meter. Johnson will have specs on it.
You can find the 419 page here:A419 Series Electronic Temperature Controls with Display and NEMA 1 or NEMA 4X Watertight Enclosures Technical Bulletin • Viewer • OpenBlue, Building Automation and Controls Knowledge Exchange (johnsoncontrols.com)
By the way, there is no SPT-48 model in Masterbuilt.
docs.johnsoncontrols.com
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Several different possibilities here. Is this the original controller or a replacement? If a replacement, what positions did you place the jumpers? What did you set as a dwell/differential? Hopefully it hasn't had the wiring for the defrost heater miss-wired or cross wired with the compressor.
The PTC (thermistor) can be tested with a ohm meter. Johnson will have specs on it.
You can find the 419 page here:A419 Series Electronic Temperature Controls with Display and NEMA 1 or NEMA 4X Watertight Enclosures Technical Bulletin • Viewer • OpenBlue, Building Automation and Controls Knowledge Exchange (johnsoncontrols.com)
docs.johnsoncontrols.com
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First, could you tell us the make and model?
It will come down to either the call for heat, or the burner not lighting.
The call for heat will be the temp control system. Or the blower motor safety, or the door switch.
Burner not lighting will be a ignition problem.
You can determine it with a voltmeter on the ignition control supply in conjunction with a digital thermometer probe in the box. Power but no heat it will be the burner/gas. No power when it should be calling for heat will be in temp control circuit. I would have to have more to find the schematic to tell you more. But the most common is the door switch or safety switch in the blower motor. However, it can be back farther in the temp control. Mechanical or digital thermostat? That requires a bit more info from you.
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Holding Cabinets have both a heating element and a humidification element. As well as circulating fans. So it will be in the 1500 to 1800 watt range. That means you will be over 15 amps if your power is below 115 volts. So it will need a 20 amp switch. (always rate at 80% load) But the secondary problem is resistance. This makes heat at the terminal that then transfers into the switch. That means you need to replace the spade connectors and maybe cut back the wires to bright copper. But also, use a good crimper and high current quality terminals. AMP makes good ones. Generally, if they have a Mil Spec, you'll be ok. The market is flooded with garbage crimp terminals.
Quality crimpers start at about $80 for reference.
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Two speed will need a common, high, and low wire. Also proofing switch that it is running before heat can come on.
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It's not likely a relay as they tend to just fail completely. If you're sure that the cook and hold function is not causing it. I'd be looking at the centrifugal switch in the motor. Or possibly heat saturation to the control board. Check to make sure the muffin fan is running at speed for cooling. Again a DVOM is the tool of choice here to find the actual problem. Being intermittent, it may take a bit. But just replacing parts willy nilly gets very expensive.