Grainfather Conical Fermenter Pro with glycol chiller wont circulate during cold crash

[JeffA.]

I am hopung some has a simple fix for me. I am using the Grainfather Conical Fermenter Pro with glycol chiller. I cold crashed and it brought the temperature down to 7C before it started to gradually rise. It can circulate out the cold side hose but it does not return from the warm side. I am cold crashing at 4C and I see ice formation on the fitting where it attaches to the fermenter. I am thinking something froze up and preventing either entry or exit from the fermenter. Does anyone have any ideas?

UPDATE:
This is more confusing--There is flow through the warm side going back to the chiller. The coolant measured 0C.

The chiller reservoir is at -5C.

i am lost

 

[bmc1313]

I’m wondering if ice built up around the sides inside the fermenter and slowed the heat transfer. Did you you take a peak inside the vessel while this was happening? I might try raising the reservoir temperature closer to the freezing point. Maybe -2C.