Lights continually flicker while heating system running
I recently purchased a home which had all the wiring, switches, outlets, panel, service, etc. replaced within the last 7 years (presumably by a qualified electrician, it was permitted and inspected). There's a 200 amp panel with 3 dedicated 240v circuits for the radiant floor heating (30 amp for pump, and 2- 50 amp for electric water heater). Lighting, outlets, other appliances, etc. are on separate circuits.
When we turned on the heat for the first time last night we noticed that all the compact flourescent and halogen lights in the house would flicker (faint strobe effect) wile the system was running. Everything I've found so far relates to lights flickering/dimming when a high current appliance turns on, not continual flickering while running. I haven't noticed this with any other appliances (clothes dryer, window A/C, or dishwasher).
With the exception of the service wires coming into the 200 amp panel, I have ensured that all the wire connections within the panel are tight. No discolored wires or insulation in there.
The symptom is not a dimming of the lights when the heating system comes on, it is continuous flickering when the system is running.
Is this symptom similar to a high current draw, or is it related to something else?