Understanding Temperature Readings
Z Grills controller’s PID software has been refined to maintain the most stable temperatures possible, but like any pellet smoker, temperature swings around the target are normal.
The grill will often overshoot the target temperature by as much as 20ºC (40ºF) before stabilising. The temperature will then swing above and below the target by as much as 10ºC as the wood pellets drop into the fire-pot in batches every 1 to 2 minutes and release heat.
An electric oven will also swing around the target temperature by as much as 15oC, but those fluctuations aren’t normally shown to you on the temperature display.
For more information about grill operation click here.
It is important to NOT be too pedantic about temperatures throughout the grill. Let the grill manage the temperatures and focus on the cooking results you are getting.
If temperatures are consistently above or below the setting then there might be a problem, in which case please contact us.
Temperature display vs grill racks
The controller reads the temperature using the vertical metal probe on the left of the grill. It then applies an adjustment in the software to estimate the average grill rack temperature. The temperature of the grill rack may therefore differ by as much as 10ºC (20ºF) from any readings you take on the grill rack. This is normal and nothing to be concerned about.
Grill rack temperature readings may be lower if close to cold meat and much higher if near the hot air flow rising up from below at the front and rear of the grease tray. It is therefore best to take a grill rack reading in a more central location and not too close to food.
Temperature above target
If the temperature rises well above the current temperature setting, it could be for a number of reasons:
- Running the grill at a low temperature setting on a hot day. Click here for more information.
- Heat released from the initial startup process (click here for more information)
- Leaving the grill lid open for extended period of time will cause many pellets to feed into the fire-pot, creating a large fire. When the lid is finally shut the amount of heat released can result in the grill significantly overshooting the temperature setting.
- A fire-out has occurred resulting in a large amount of pellets in the fire-put and excessive heat output. Click here for information about fire-out occurring.
- Wood dust (from bottom of bag of pellets) dumping into the fire-pot and release large batches of heat causing temperature spikes. Avoid pouring wood dust into the hopper. If the pellets have lots of dust, even consider giving them a sift. Click here for more information about wood pellets.
What to do?
- Open the grill lid until the temperature drop down close to the temperature setting on the grill. Don’t leave the lid open so long that the temperature drops below the setting otherwise even more pellets will be delivered, further increasing the temperature. The lid can be opened a few times to bring the temperature down, for for no more than 1 minute at a time.
- Expect the temperature to still climb back above the target for a period of time before gradually dropping back down and stabilising.
Hot weather grilling
If using your Z Grills smoker on a hot day, it could reach 40 to 50ºC just sitting out in the sun! So with even the smallest fire burning, it is very hard to maintain temperatures below 100ºC.
In hot weather don’t try and use the smoke or even 82oC setting. Using these settings can result in the temp dropping (fire going out), re-lighting and spiking back up. A much better approach is just to set at 107ºC or higher. At 107ºC you will still get plenty of smoke but less temperature fluctuations.
Hot weather tips:
- Set the grill to 107ºC, which still provides plenty of smoke.
- Take the grill out of direct sunlight.
- Blow a fan across the grill (not at the chimney) to increase heat loss which will bring the temperature down.
- Use a small ball of foil to hold the lid open slightly to allow more heat loss.
- Place a tray of water in the grill. Water uses lots of heat to evaporate, so will help bring the temperature down.
HER error
If the temperature rises very rapidly or suddenly jumps to a high temperature the temperature sensor may be the culprit. This can often result in HER (high temperature error) being displayed on the screen.
Click here to diagnose and fix a faulty temperature probe.
If the temperature gradually keeps on climbing up to and beyond the maximum temperature setting of 232ºC, the auger may be running continually, delivering wood pellets into the fire-pot. Eventually the HER error may appear on the screen.
For either of these above issues, please contact our support team.
Temperature spike after startup
During the first 5-7 minutes of startup (switching from Shut Down Cycle to Smoke) lots of wood pellets will be dropped into the fire-pot to establish the fire. These pellets will release a lot of heat and easily take the grill temperature up to 140ºC (280ºF), especially in hot weather.
If you are planning to cook at a lower temperature than this, place a ball of foil (or similar high temperature material) under the front of the lid to hold is slighly open, allowing more heat to be released. This will all the temperature to come back down more quickly.
Don’t open the lid for extended periods (more than 30 seconds) as the temperature sensor will read a low temperature from the outside air coming in and the controller will deliver more pellets into the fire-pot result in a temperature spike once the lid is closed.
Get up to temperature fast
If you are planning to cook at a high temperature (>135ºC), shut the lid as soon as the first big cloud of smoke begins to clear after startup. This will help get the grill to the desired temperature more quickly.
Always start the grill with the lid open to allow flammable vapour released from the wood to vent out. Starting the grill with the lid shut can potentially lead to a dangerous gas explosion!
Changing from high to low temps
If the setting is changed from a high temperature to a much lower target it can take a long time for the temperature to drop, especially in hot weather. This is due to the fact that a fire is always maintained in fire-pot, so continually releasing more heat.
To speed up the temperature drop, follow these steps:
- Set the controller to the desired lower temperature target.
- Open the grill lid.
- Once the temperature on the controller gets close to the target temperature, close the lid. Do not let the temperature drop below the target or more pellets will be delivered to the fire-pot.
- If the temperature spikes far above the target again, open the lid again (and repeat).
Fire-out during temperature drop
Changing from high to low temperatures can sometimes result in the fire going out, especially in very hot weather. This can happen if the grill temperature is far above the target so very few pellets are delivered into the fire-pot, which can result in the fire going out.
Click here to learn more about fire-out and what to do.
Temperature won’t reach target
Check fire-pot for ash
If the grill can’t reach the target temperature, the first thing to check is that the fire-pot has been recently cleaned of ash. A thick bed of ash can smother the fire.
Low heat output pellets
Some wood pellets, especially soft wood varieties, can have low heat output (low energy density) and will struggle to reach high temperatures. Moist pellets will also provide poor heat output and also risk the fire going out.
Try using a hardwood pellet, or type that you know can reach high temperatures. If confirmed that the wood pellets are the problem (but not serious moisture issue), don’t throw them out, you can mix some of them in with good wood pellets to gradually use them up.
Not a problem with wood pellets?
If the temperature is not able to reach the target with pellets that you know are fresh, dry and have worked well in the past, it may be a problem with the grill.
Try these steps to check the operation of the grill:
- Take out the baffle, grease tray and grill racks so you can see in the fire-pot
- Start up the grill and once the fire is established, turn the controller dial to the highest temperature setting.
- Watch the pellets dropping into the fire-pot. The auger should rotate almost continually delivering pellets, pausing only for a few seconds every minute or two. Do NOT shut the grill lid without the heat baffle and grease tray in place, as the open fire can burn the drum paint or damage the temperature sensor.
- If the auger is pausing for long periods please contact us for assistance.
- If the auger is rotating almost continually, put the baffle and grease gray back in, shut the grill lid and let it run for at least 30 minutes and see what temperature is reached.