Question about Bunn Coffee Makers & Espresso Machines

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My model bunn grx-b stopped working. Checked continuity on tank, fuse on tank, bottom switch, can top switch be at fauLt? If so how do I remove it?

Posted by Pat Trevino on


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Mark Cheong

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Bunn switches if the rocker style as the looks like will have two leaves on the side of the switch that will need to be squeezed in order to get it past the square hole. These can be really tight but if your sure it's at fault then just crush it to remove the pieces. The new on should snap in if the hole was not damaged.
* Since your checking the brewer you should get the manual that may be available from (I haven't checked for this model but they usually post the manuals)
* This seems to be a home version of a VPR commercial brewer (but nicer). So expect the same parts for the fuse, thermal fuse, thermal disk (or thermostat).
* Note: If your not familiar with Bunn brewers then make sure you look at every piece of wire as some high limit fuses are inside plastic tubing or heater braiding.
* Thermal disks look like a metal button with a ceramic cap or button attached to it. This can be a high limit (reset-able) or a thermostat. * It may have a standard thermostat with bulb but it may be a thermsistor probe with a PC board to control the brew heat.
* Final; this is the 3d question on this particular brewer. All have similar problems with heating. It's the same with VPR's. If I set them up I know it works properly. It's when someone moves them to another office that's the problem as they dump out the water prior to the move then plug it in without refilling the tank. Thermal fuse blows. There is a link below showing how to set up this brewer.
Aloha, ukeboy57

Posted on Jan 20, 2018


5 Related Answers

Gord Thurston

  • 131 Answers

SOURCE: BUNN Pour-Omatic

Most likely it is your tank heater, but look on the top of the tank heater, because sometimes the wire will burn off the top of the element

Posted on Feb 11, 2009


Leroy Elliott

  • 3085 Answers

SOURCE: MY Bunn coffee maker GRX leaks .

Complain loudly to Bunn, they fixed mine for free.

Posted on Dec 09, 2009


  • 189 Answers

SOURCE: Bunn GRX-B leaking from bottom

If you will locate the date code on the bottom of the brewer and contact Customer Service, the machine can either be replaced or repaired at not cost or if over 3 years old, at a reduced price.

Posted on May 19, 2010


  • 189 Answers

SOURCE: I need a wiring diagram for a Bunn BX coffee maker

I do apologize but these diagrams are not available. What is the problem with the machine? If you will get the model and code date from the bottom of the brewer and contact customer service, we can help resolve your issue. The machine carries a 3 year warranty and if it is 3 years old or less, it will be replaced at no cost. If it is older than 3 years old, then it will be replaced at a reduced price.

Posted on May 19, 2010


  • 189 Answers

SOURCE: My Bunn has a slow drip. Model GRX-B. Have

How old is the machine? If you have cleaned it and delimed the machine and it still is dripping slow, the machine may need to be replaced. Please call service at 800-352-2866 with the model and date code.

Posted on Oct 20, 2010

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1 Answer

I've bypassed the blown thermal fuse, but still cannot get anything to come on.

Call for service! Repairs should be performed by a qualified Bunn tech.
*** the following is for information only ***
* Thermal fuse blows due to no water in tank and/or over heating.
* Depending if the tank was empty and how hot the element got will determine what blows.
* If it was completely dry when plugged in then the element got cherry red hot and may have melted gaskets as well as all the fuses.
* Depending on the model, there may be 2 thermal fuses or even a 3d on the thermal blanket.
* If the brewer was filled but left on for a long period (weeks?) then the tank just boiled off till the fuse blew. Good chance the element is ok. But have to check to be sure.
* No model given so I'm guessing a VPR or similar pour over (BXB series) These blow out when not properly filled before powering up.
* VPR's .usually have a normal load on from the warmer blanket. The load (amps) will kick up on the initial heating of the tank (filled with water) then drop down after reaching temperature.
* There is an additional load if any warmers are turned on.
* The on/off switch on a VPR will activate the main heater element AND the brew warming plate (Blanket stays on all the time)
* Easiest way to check is amperage loads on each section. Continuity is a bit harder as it does not tell you if it's shorted (unless you know the resistance loads to begin with)
* Final: Get a qualified service tech to check just to be safe.
Aloha, ukeboy57

Feb 04, 2016 | Bunn GRX-B

1 Answer

Bunn GRX-B won't heat and yes it is plugged in and vacation switch is on

You said "...turned vacation switch back on". In fact, it should be turned off for normal use.

If that's not the problem, and it's plugged into a GFCI outlet, press the RESET button (do not press the "test" button).

If still no joy, plug something else into that outlet to see if it works. If it doesn't, check the circuit breaker for that outllet.

Jul 14, 2014 | Bunn GRX-B

1 Answer

Will not heat

there is a white felt like tube on the top of the tank after you remove the top you will see this slide it out and replace the 2 microtemp fuses part number g4a01 at 141c. or 285.8 f use 2 of them just like they are in the unit . if too mutch to handle call bunn if under 3 years they will replace whole thing

Apr 17, 2014 | Bunn GRX-B

1 Answer

Is there a current recall on Bunn model GRX-B?

Don't know about a recall, but the most common cause is a bad element.

Jan 22, 2014 | Bunn GRX-B

2 Answers

My Bunn Thermofresh quit heating the water.

The Bun BTX-B has a pair of thermal fuses located on top of the water heater storage unit. If the pot is left without use for a week or so, the thermal fuses will blow if the top of the tank gets too hot (about 150 degrees Fahrenheit) due to the evaporation of water in the storage tank. The operating directions state clearly that if the unit is not going to be used for a few days to turn off the pot. These are there to prevent a fire in case someone does not follow the direction. This is the "MOST" common form of electrical failure in these pots.

To access the thermal fuse
1. Unplug the pot and drain pot by inverting the pot in an empty sink.
2. Remove the two Phillips screws located under the water fill flipper door.
3. Gently insert a small flat blade screw driver into the front top of the lid and remove top cover.
4. Remove the 4 screws inside the water routing tank and remove routing tank simply by lifting off.
5. The thermal fuse is mounted to the top of the tank under a clip and is easily slid out from under the clip. There is a brown wire (goes to power cord neutral) and a black wire (goes into tank disk access hole). Simply measure with a multimeter at lowest ohm setting, the meter should read continuity between the black and brown wires, if it reads an open circuit, the part is bad.

A replacement thermal fuze assembly kit is available off e-bay for about $10. You can buy individual thermal fuzes and replace one of the two that is bad for about $3, but I recommend the kit for most consumers as it comes with wire crimps already mounted and far easier for the average person to simply install. Repair takes about 5-10 minutes.

Mar 03, 2013 | Bunn BTX-B ThermoFresh 10-Cup Home Thermal...

1 Answer

I have an Bunn model GRX-B datecode 304009 that leaks at the bottom, what can be done about it

Most likely cause is that the seal between the water reservoir and the tank is leaking. Not uncommon. If you can find a replacement seal go for it, otherwise the old one can be made serviceable by coating both sides with a thin bead or layer of clear silicone. Allow to cure for 24 hours before powering the coffee maker back up.

Dec 26, 2012 | Bunn CWTF Coffee Makers & Espresso...

1 Answer

No power getting to Bunn coffee maker

Okay, When going away most people empty the tank completely. When returning you must start it as if brand new out of the box. Follow the MFR's instructions for an initial fill and heating.
Some don't empty but just unplug just as you did. Places like Arizona with very low humidity can dry out or lower the tank water where the heating element is not in water. This element will overheat and trip out the thermal fuse.
**Another scenario is the empty unit was plugged in and heating while someone was going to get the water. Over heat then blows fuse.
** The "Vacation" switch is very visible so you probably have tried it already and you have already checked the outlet and breakers. Still looks like a thermal fuse problem.
** Switches do go bad as they are turned on and off daily. Possible yours was bad before but never noticed as it was never turned off till on vacation.
** There are other possible scenarios but all point to a thermal fuse, thermal limit, blown fuse, switch, Heater element, or cut wire (Mice). All are electrical problems and require a MFR tech. Contact your vendor or MFR for service.
*Have a safe New Year, Aloha! ukeboy57

Dec 25, 2017 | Bunn GRX-B

1 Answer

I have a Bunn GRX-B Model Serial # 243908. It is leaking water while brewing at the bottom on the on/off switch side. What is needed to correct this? It is more than 3 years old.

Your brewer is still under the 3 year warranty. If you will call us at customer service at 800-352-2866 we will be happy to send you out a new machine.

Dec 09, 2010 | Bunn GRX-B

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