Protect thermostats from damaging low voltage pathways from outdoor heat pumps.
TPD-xxSLPyy (Example TPD-24SLP4 which is a 24V, 4 wire protector)
XX = Operating Voltages 10V, 15V, 24V, 48V, 120V and 190V
YY = 2, 4, 6, 8, 10 and 8-RJ45
Max Amperage: 400mA
Max Data Rate: 10Mbps
Response Time: < 1 nanosecond
Strength: 16kA per pair
Ten Year Unlimited Free Replacement Warranty
Series Resistance: < 0.1 ohm
Enclosure Type: High impact, Non metallic
Din rail or screw down mountable
Count number of wires coming from each outdoor heat pump to the air handler. Protection for thermostats are not done at each thermostat. Surge protection should be applied to the exposed pathways that come from outdoor heat pumps. So if a home had 20 thermostats the trick would be not to protect all 20 thermostats but to protect the pathways coming from the five outdoor heat pumps.