Thread Number: 84978  /  Tag: Small Appliances
Sunbeam C-20b How to Adjust the High-Low Thermostat
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Post# 1094379   10/24/2020 at 16:55 by 53cmcoffee (PA)        

Hi all I just purchased a Sunbeam Coffeemaster C-20b with the creamer and sugar bowl in very good condition. I purchased Yama cloth filters from Amazon which fit nicely had to cut the hole to fit the filter holder . A really beautiful coffee pot.

I was very excited to use the pot and make some good tasting coffee after reading all the blogs on making coffee in the Coffeemaster.

Got the pot ready to test first with water, plugged it in switched the pot to High it began to get hot water started to boil and then the pot switched to low before the water was boiling long enough for it to go to the upper pot. A little disappointing to say the least. Hoping this is a fixable problem.

Was wondering if any one out there has had this problem with their Coffeemaster? what did you do to fix the problem, did you have to make an adjustment to the thermostat switch for the C-20b? If so can you please share your knowledge on how you made the adjustment or any other trouble shooting tips you may have.

Post# 1094391 , Reply# 1   10/24/2020 at 17:47 by ea56 (Cotati, Calif.)        

ea56's profile picture

If the water began to boil then it should have also began to rise.  Maybe the gasket is sealing completely and therefore the vacuum isn’t strong enough to complete the rise to the upper bowl.  


Try again and make certain the the upper bowl is firmly pushed down into the lower pot, and you also have to have the filter and coffee in the upper bowl for the water to rise and hold long enough to the coffee to brew.  


Many years ago, before I knew anything about these pots I bought a Coffeemaster at the Salvation Army.  It didn’t have the filter assembly, and I didn’t know it needed one, so the same thing happened to me.  The water boiled, but it didn’t rise, because there was nothing in place to hold it up north for a brew.


Good Luck, and I hope this helps.



Post# 1094414 , Reply# 2   10/24/2020 at 21:09 by MattL (Flushing, MI)        

The thermostat is a bit tricky to adjust. There was a special tool used to do it, there is a not within a nut if I recall. You can do it with some needle nose pliers bu it's tricky. I adjusted mine and would get occasional boil overs after, others report the same.

I'd look at every other option as being the cause before I messed with the thermostat.

Post# 1094416 , Reply# 3   10/24/2020 at 21:15 by ea56 (Cotati, Calif.)        

ea56's profile picture

I had the same experience with adjusting the thermostats on 3 different Coffeemaster’s, thats why I suggested being sure the upper bowl is firming seated and have the filter and coffee in place.  I agree those thermostats are difficult to get to, to adjust and can cause more trouble down the road if the adjustment doesn’t hold or isn’t correct.



Post# 1094805 , Reply# 4   10/27/2020 at 12:50 by Tomturbomatic (Beltsville, MD)        

C20 is the Coffeemaster style with the flat gasket and the screw down filter holder that holds the two bowls together, right?

Post# 1094806 , Reply# 5   10/27/2020 at 13:00 by ea56 (Cotati, Calif.)        

ea56's profile picture

Yes Tom, you are correct.


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