Hi, I have a Keurig coffee maker (model B70). At first, the water would run back into the reservoir when brewing, but I didn’t feel it to see if it was hot or cold. After a couple of times, the only way it would brew is if I put my finger over the reservoir return tube holes (causing bubbles to come in through the bottom). After a few times doing that, the water coming out of the brewer would not be a full cup and only slightly trickle out. Also, it won’t allow the cup size to change (it’s stuck on the large cup setting). The water coming out of the brewer is always hot. I have de-scaled it and also cleaned the holes out with a paper clip. I’m not sure if this is the solenoid, the air pump or both? Any ideas? Thank you PS – it’s over a year old, so I don’t have a warranty any more.
It sounds like Copper has worked through some of our suggestions over on our guide for when water is being discharged back into the water reservoir (you can access the guide through this link on our site).
As we mention in the guide, and what Copper is asking about, is what is required to fix the water pressure regulation in the machine. We know there is water pressure problems as a Keurig demonstrates this in two ways. The first is through pumping water back into the water reservoir and the second by brewing a partial cup of coffee (we have another guide providing more background on this problem here).
The third issue, and we think perhaps unrelated, is the cup size selector being stuck on large. We’ll come back to this at the end of this article.
Water Pressure Regulation
As the problem is described by Copper and the steps taken so far in de-scaling the machine and ensuring the needles are unclogged (and we are assuming the Keurig Burp has been tried too as it’s mentioned in both of the guides linked to above), we would go for both the solenoid and air pump replacements.
The solenoid replacement should fix the first problem of the machine dumping water back into the water reservoir as the solenoid is a key device in regulating the water and air pressure in the boiler unit. Our guide covering this replacement can be found here. The part you are looking for is pictured below and costs between $10 to $20 from amazon or ebay. We have more details about and other parts on our spare parts replacement page.
The air pump replacement should fix the partial cup brewing problem as this, along with the solenoid, is the key device used in building air pressure in the boiler unit: which is then used to draw the heated water out, pump it across the top assembly in the B70, and then into the waiting K-Cup in the portion pack holder. And all going well, then hot coffee into the waiting coffee cup.
The part you are looking to replace is pictured below and they also cost between $10 to $20 on amazon or ebay. We also have a guide to step you through this replacement and as the pump sits right next to the solenoid unit (see second photo below) there isn’t a lot more work involved compared to just replacement one of the parts by themselves. In the second photo the solenoid is the blue cylinder and the air pump is the silver cylinder on its right.
Cup Size Selector
Normally any problems with the cup size selector do not relate to the issues we have just covered above. What the usual fault is with the sensors underneath the buttons, which are connected to the main logic / processor board, or a resistor on the main board itself that relate to the button selection function.
We have found the easiest and quickest way to deal this problem is to replace the whole board itself (which includes the LCD screen etc that comes attached). This will cover any faults in the button connectors and any components on the board.
We have a guide that steps you through this process, with full description and photos. A new board will also cost between $10 to $20 (seems to be the price bracket for most Keurig spare parts). A new board looks like the one pictured below (this was taken from our B60, but a B70 board is similar). We have more details again on our spare parts page.