Is there a fast 'n dirty way to kill the line spiking that occurs when
an inductive load is turned on sometime other than at zero-crossing of
the AC cycle?  A capacitor kludged in somehow, etc?

I've got a microcontroller that is running a bunch of valves and pumps
in a big instrument washer, and almost everything is being switched with
zero-crossing solid state relays, so that stuff stays "quiet", AC-wise.
But there's one steam valve that gets turned on by a mechanical relay
in the water tank fill/thermostat system, and it's not under control
of my SSRs, and it does sometimes generate/radiate a spike that resets
one of my peripheral chips.  My software times out and tries again, but
I'd love to just tack in a magic spike-killing fix that would avoid having
to do some major rewiring/redesign.  A varistor would help but might not
be sufficient.  Ideas?
