[QUOTE=RANGER1;331838][QUOTE=limerick14;331834]

I wish I could attach something to this thread but it won't let me.
About the check. Yes, sometimes the spring is removed or weakened by heating it up with a blowtorch.
The HGBP is just a regulator. It works like this. The backpressure control valve (BPCV) on the compressor is let's say set at 150 PSIG. This means until 150PSIG the BPCV is closed. This is because we need at least 150PSIG to get the compressor oil moving through the system. When the Compressor starts, this is typically achieved within seconds. Once we hit 150PSIG the valve goes quickly to full open. However, the volume downstream of the BPCV is much larger and requires time to be pressurized. As we also need to get the suction side of the compressor going we need to get propane to go to the chiller but without pressure, it can't go. Hence the HGBP opens. The HGBP regulator or control valve is set around 25 PSI lower than BPCV set point is. This makes gas go on startup straight into the receiver but closes the HGBP once 150PSIG is achieved.