Tom_Austin
New member
- Mar 30, 2026
- 1
- 0
HI, our beloved Bonavita drip coffee maker has relatively few electrical parts: Main switch, heating element, caraffe warmer, two thermal fuses (working) and water pressure switch. There is no thermostat or heat limit switch other than the two thermal fuses.
The tank sits five inches above the bottom of the heating element. Water from the higher tank gravity flows through the pressure switch ports into the bottom of the heating element. With enough pressure, the pressure switch closes (turns on.) I've traced out the circuit to find two thermal fuses secured to the heating element. Other than the main switch and water pressure switch, there is no other device to cut power when the element gets too hot.
I inadvertently mis-adjusted the water pressure switch. Now I need someone to explain how the water pressure switch is supposed to work. When running normally, the coffee maker rains water over the grounds in brief spurts lasting a few seconds, then there's no rain at 5-10 second intervals. I'm wondering if the water pressure switch controls that interval.
The specs at this link show that the switch is normally open. https://www.airpressureswitch.com/product/coffee-machine-pressure-switch
Currently my switch is adjusted where it's normally open. I can get the switch to close by plugging one hose end and blowing in it with about the same pressure as blowing up a balloon. So I belive it works.
There's no doubt that this pressure switch must be closed in order for the element to get power. My question is if it is supposed to be set just enough for the static water pressure is enough to close the switch to provide power to the heating element. If that's the case, the switch is already on, so how would it be able to turn off once there's too much pressure in the heating element? THANKS.
The tank sits five inches above the bottom of the heating element. Water from the higher tank gravity flows through the pressure switch ports into the bottom of the heating element. With enough pressure, the pressure switch closes (turns on.) I've traced out the circuit to find two thermal fuses secured to the heating element. Other than the main switch and water pressure switch, there is no other device to cut power when the element gets too hot.
I inadvertently mis-adjusted the water pressure switch. Now I need someone to explain how the water pressure switch is supposed to work. When running normally, the coffee maker rains water over the grounds in brief spurts lasting a few seconds, then there's no rain at 5-10 second intervals. I'm wondering if the water pressure switch controls that interval.
The specs at this link show that the switch is normally open. https://www.airpressureswitch.com/product/coffee-machine-pressure-switch
Currently my switch is adjusted where it's normally open. I can get the switch to close by plugging one hose end and blowing in it with about the same pressure as blowing up a balloon. So I belive it works.
There's no doubt that this pressure switch must be closed in order for the element to get power. My question is if it is supposed to be set just enough for the static water pressure is enough to close the switch to provide power to the heating element. If that's the case, the switch is already on, so how would it be able to turn off once there's too much pressure in the heating element? THANKS.
