Only 110V ACROSS HEATER?

[Jack]

Replaced heater element but only testes 110v across heater posts, any suggestions???

[Mary]

How are you testing? If you check voltage on one terminal post to ground you are only going to get 110V. To test a 230V spa heater you need to do a combined reading, meaning one meter probe on each terminal post at the same time. If you did test with both meter probes on each terminal post then check incomming power to the spa to verify you are getting 230V. You should again do a combined reading across and black and red power wires. If you have 230V comming into the spa but still are only getting 110V to heater you may have a bad heater relay on the spa circuit board.