Switched my TIGRIS 1000ltr 2 yr old hot tub off in October, thinking it would stay off for a while. Had a rethink and started it back up today. Water still in from summer and was due to drain and clean it.
Left it on in standard mode 38 degrees. Came back a couple of hrs later to find it was constantly in blower mode and the temp was still at 4 degrees and no heater on. When I depressed blower motor button on control panel, heater light came on for about 20 seconds, flickered and the sign: "1C" or "IC" illuminated in control panel window and the blower came on continuously again - heater light went out and temp sat at 4 degrees while the bubble blower continued to run???
Handbook says that "IC" stands for icing conditions deteced - no action to be taken????

How do I override the blowers so that the heater can stay on to heat the water?

many thanks in advance.

The blower is on to keep the water moving as it heats. The only way to stop it will be by disconnecting the power to the blower.