Antminer S17 is Temper-mental, as are S19, S9, T17, T9, L3+

Why do Bitmain's hashboards shutdown in cold and hot climates? How should you fix this?

Despite best efforts, interior climates of mining farms may be difficult to control in periods of extreme heat or cold. This winter was no different. Bitcoin mining facilities in China faced frigid temperatures, causing machines like the Antminer S17 Pro and Antminer S19 to automatically switch off hashboards. This safety feature is actually beneficial. It acts as a self-preservation mechanism for the hardware during unsuitable running conditions.

China cold snap 2021 Jan parody
Chinese weather parody Jan 2021, author unknown

If you were unaware, a large proportion of Bitcoin’s hashrate flows in from China. In fact, 20% of Bitcoin’s hashrate originates from the western province of Xinjiang. Temperatures here this January dipped to below -20 Celsius (-5 Fahrenheit). Furthermore, humidity was over 80%, making it feel even colder.

Antminer Running Temps

As mentioned, cold or heat spells can cause Antminers with temperature safety features to stop working. As far as aware, these models include the S9, L3+, T9, T17, and the S17 and S19 series.

Although it is possible to run machines between 0C and 40C (32F – 104F), most miners prefer to operate above 5 C (41F). Bitmain recommends an ambient running temperature between 15 – 35C (59 – 95F).

If a machine pulls in air through its fans below -5C (23F), it automatically goes into ‘protection mode’ and shuts down the corresponding hashboards whose sensors report low temps. The same goes for temperatures which are too high. Sensors reading above around 85C (185F) also trigger hashboard shutdowns. Refer to this guide for the suggested degree ranges per model.

Mining Farm Ventilation

Bitcoin mining farms usually have large wall-mounted fans which are essential to cool ASICs down during warm summer months. Typically these humongous fans pull cooler outside air into the building, drawing it through the shelved mining rigs, then up and out through ventilation shafts in the mine’s roof. In the winter, most mines only heat themselves by the thermal output of their own operating rigs.

Anonymous mining farm’s intake fans in cold temps with high humidity and ‘ice fog’. Fan icing caused interior farm temperatures to become too high as air circulation was blocked.

During cold winter months large amounts of snow collected on the roof or around the farm structure could inhibit correct air circulation dynamics. Additionally, water condensation combined with low air temperatures may cause ice build-up on a farm’s fans.

Ultimately, freezing outdoor temperatures may cause interior farm temperatures to plummet and machines to shut down. Contrarily, blocked ventilation may cause interior farm temperatures to become too high. Mine air circulation must be unobstructed before handling miners that have lost hashing power due to temperature.


Getting the Cold Antminer Back Online

When “chilled to the metal”, Antminers need some coaxing to get back online and achieve full hashing capacity. Below is a summary of the steps to succeed in preheating an Antminer. Although, please refer to Bitmain’s own guide for a detailed account of maintaining bitcoin mining machines in low temperature areas.

The Scenario:

S19 freezing, hashrate drops
S17 looses hashing power suddenly on the 7th Jan. The lost hashrate was recovered on Jan. 8.

An Antminer S17 Pro 56 TH/s has lost hashing capacity during a cold spell this winter. The mining machine operator force drops from 56 TH/s to nearly halve, at 35 TH/s. It looks like a hashboard may have failed. See the graphical image of the hashing speed from the pool’s data.

Miner Status page for Antminer S17 Pro, note that some PCB temperature sensors report very low degrees.

After further inspection, the Miner Status page shows that some of the printed circuit board (PCB) sensors are near to zero degrees. The kernel log reports a warning message, something like: “PCB min temperature (-6 C) is too low, <= -6 C”.

Thus, two of the three Antminer S17 Pro hashboards are not performing as expected due to the cold. The preheating startup method gets them back online.

Steps to Preheat an Antminer ASIC

1. Direct restarts are avoided in low temperatures. Check for loose heat sinks or chips if the miner was recently moved.

2. Redirect the hot air expelled by the machine back onto itself, by repositioning the unit’s angle on the shelf. Incoming and outgoing air in the vicinity of the hardware is also checked for obstruction.

3. If after a time the machine is still underperforming, it may be shut down and moved to an area with a temperature over 20C (68F), until the internal temperature has risen to at least 5C (41F). One farm operator reports to Miner Daily that ‘heating tables’ are sometimes used to evenly warm up miners.

Note, Bitmain stresses that equipment producing extreme heat concentrated on one area, like fan heaters or blowdryers, should not be used. Such apparatuses could potentially damage ASIC components or loosen soldering. Humidity should also be minimal in and around a Bitcoin miner during running. Thus, preheating helps to expel unwanted water vapor.

4. Still having issues? Contact Bitmain or a repair center.

Additional Notes on Antminers in Cool Climates

Units which have just arrived at a farm need preheating as well as checks for loose parts or damage. In colder regions, Bitmain recommends starting the machine mid-day when outdoor temperatures are at a maximum. Further, it is vitally important that the firmware, IP, and pool settings are updated before initial boot-up.

Sum Up

Bitmain’s protection mode is a great tool for Bitcoin miners. So long as temperature sensors are working correctly, this mechanism helps to prolong an ASIC’s lifetime through ensuring the hardware runs safely. Remember to attend to ventilation issues before the miners. Avoid cold restarts by preheating machines.

Now, go smash the hash bitcoin miners! ⛏⚙️⛓

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