Bunn GR Home coffee maker

Old 02-05-17, 05:25 AM
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Bunn GR Home coffee maker

Does anyone know anything about these?

I just got a used one and have had one a few years ago.
I know they're supposed to brew at 200° but I'm only getting 160° in the pot.

The old Mr Coffee I had to replace because it started leaking seemed to be much hotter. Major amount of steam coming off it and could almost burn my lips if not careful.

When I pour the coffee from this Bunn it has steam coming off the cup but nowhere near the same and I can drink it no problem without burning myself.

Is the heating element weak in it? I've read that that the thermal fuses can go bad but they usually cause it to not heat at all.

I can't find any info about repairing them other than the fuse.

Can anyone point me in the right direction?
Old 02-05-17, 05:53 AM
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The last home Bunn coffee maker I worked on had a thermistor in the tank to sense water temperature with no ability to adjust temp on the cct board.
It should operate in the range of 190 - 200 degF.

There are a few things you can check.
Make sure there is no chance the tank is full of scale, that the spray nozzle is present and not plugged, that the coffee maker tank is full of water and has been plugged in for at least a half hour and that the coffee grounds are at room temperature.

Some people prefer a lower brew temperature.
Coffee brewed at a slightly lower temperature should be a bit smoother.
If the taste of your lower temp coffee is good you could put the carafe in the microwave for a minute to make it hotter.

Or just get a new brewer.
Old 02-05-17, 06:41 AM
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Have you looked at the current thermistor to see what it's cut-out temperature is ?

I've replaced a lot of thermistors because they begin slowing down in their reset; not because they failed to achieve the desired temperature. The slowing down is a sign of impending complete failure, and the need to replace them.

I've bought them on eBay; but you must purchase about a dozen at a time to get a decent price.
Old 02-05-17, 07:16 AM
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Just a note to clarify something.
A thermistor is a resistor that varies its resistance according to temperature.
They are connected to a circuit board that senses this resistance to switch a relay to control whatever the thermistor is sensing.
Many circuit boards that are controlled by a thermistor have an adjustable knob (potentiometer) to be able to adjust the temperature.
It may exist but i have not seen a Bunn home coffee maker with a thermistor that can adjust this temperature.

It is possible that there is a mechanical thermostat used on this Bunn home coffee maker that can be replaced but it will have to be dismantled to see what's inside.
Old 02-05-17, 09:00 AM
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One more thing.........You are measuring the temperature in the pot.

It is customary when servicing a drip coffee maker to take the temperature of the water in the basket above the grounds.
If you get picky about temperatures a cold carafe and even the length of time it takes the water to get through the grounds can affect temperatures of the final product.
Old 02-05-17, 09:52 AM
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I had a similar machine. It used a clixon snap type switch to sense tank heat.
What's the full model number of yours ?

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