T30 model 242 Safety relief valve pops off at 50-60 lbs pressure. Put on a new one and still the same problem. Don't know what to look for next. Normal cut out is at 150-175. Thanks

I don't find that model in my database but if the safety valve is popping it is one of only a few issues:
1) The safety valve is weak or defective - run the compressor and watch the pressure gauge and see when it releases. Most compressors cycle on at around 90psi and off at around 120psi - the relief valve is usually set at 130-140psi. If it releases before 130psi I would replace the safety valve.
If it blows off above 130psi...
2) The pressure switch is defective if the unit doesn't shut down at it's labeled pressure (most are 120-125psi)
If it runs beyond the labeled pressure and blows off then replace the pressure switch.
3) If the unit has a pilot valve instead of a pressure switch and the unit builds up past the labeled pressure then you can follow these instructions to adjust https://www.youtube.com/watch?v=6CZ9Hznh6EI

The over-pressure relief valve may be defective if the valve is opening before the desired tank pressure is reached. If not, then the shut-off pressure adjustment (if there is one) may be set wrong. You'll need to find out from the manufacturer exactly what static tank pressure the compressor is designed to provide and then determine if it is working correctly. If so, then the relief valve might be defective. DO NOT attempt to defeat the relief valve under any circumstances - it can result in compressor damage or a dangerous tank failure.

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One of the valves is broken. need to replace valves.

Pressure relief valve is sticking. Shoot it with some PB Blaster.

You didn't give the model of your compressor so, for an electric model: Check your gages while the tanks are filling. If the pressure gets to the rated high pressure level for your model and keeps going until the relief valve pops, the problem is with the pressure switch. It isn't turning the motor off when it's supposed to. If the relief valve pops before getting to the max pressure the tanks are supposed to be at then the spring in the valve is broken or weakened to where it pops too early. Replace the relief valve.

"Protector Valve" could mean several different things. There is "pop-off" safety pressure relief valve and there is a "Thermal Relief Valve". Your pump could be protected with both, or only one of these. A pic would nail it down quickly.
Don

check and test the capacitor or power source --to long or not correct extension cord --to small a breaker for load start

With Graphite gaskets the torque is 34 lbs.

Generally, the safety/relief is set to 140 to 160psi. The pressure setting is stamped on the side of the valve. Replace the valve if it will not hold stamped pressure(cost about $6 at Lowes Lumber).The pressure switch is usually set at the factory to 120 - 130 psi. The unloader part of the pressure switch will not release backpressure unless it reaches set cut-off. The 1/4 inch line attached to the pressure switch connects to air discharge tube at the intank checkvalve (brass valve). The safety valve should very rarely release pressure, only when pressure switch malfunctions and allows pressure to reach up to 160psi. The tank will hold over 300psi so dont worry about the 160psi safety. I am not sure about your exact model number or brand, however most small compressors work the same and share similar parts. For manuals to other similar compessors to to www.dewalt.com. Here you will find manuals to dewalt and porter cable compressors. I prefer to use generic replacement parts from www.grainger.com or from Lowes Lumber. These parts will cost less than factory replacement. If you need to replace the pressure switch, use SquareD brand from grainger. Watch fitting sizes and pressure range. Good Luck on your repair.

your make up water pressure is greater than the safety relief pressure. The safety should be 30psi lift. the makup usually goes through a regulator called an automatic makeup valve. these valves operate infrequently on a closed system and get rusty. They stick. If yours is stuck open, then your makeup water pressure which is probably greater than 30psi is overpressuring your boiler.