hot gas bypass

[firewod]

Sporlin sdr-4 hot gas by pass, dumps in just after txv valve into evap. Valve is still opening and closing even after temp. control board has stopped sending signel. Pid control, valve & board have all been replaced still no luck, maybe getting a backfeed? Any help thanks. P.s. unit is 30ton process chiller

[gerryboy00]

is it possible that your board is use like a interface and be control from an external controller, ?

[DenisL]

Is the jumper on the tcb board in the right position or is logic inverted?
DenisL
Lowtemp enviormental chambers

[richper]

More info. please. Pressures, temps, etc. Try isolating valve and watch your suction ,valve may be doing its job due to low charge or starving evap. from improper metering. Again a little more info please.