We have found that most of the TX7 models are used by specialized breeders for their Macaws, Cockatoos, Eclectus, etc., while the TX6 is primarily used in the schools for their spring science programs to hatch chicken, duck, quail or even goose eggs.


With either unit, we provide fan forced air flow for even heat distribution around the eggs, the optional automatic turner, as well as a set of thermometers.  Both units also use your choice of one of the five turnings rings, so a variety of eggs can be incubated and hatched.


The two major differences are found in the temperature control module and the thermometers that read temperature and humidity.  The thermostat of the TX7 model utilizes a “Ten Turn” Potentiometer, whereas the TX6 model has a “Single Turn Pot”. This means that on the TX7 you can adjust or fine-tune the temperature more easily and accurately for your specific requirements, especially at hatching time when the temperature is usually lowered.

The TX7 model uses “Spirit” alcohol thermometers for accurate temperature reading, while the TX6 model easily reads spirit carded thermometers. Since most TX6’s are used in schools, these are supplied as they are easier for children to read and understand.  Go to the section on thermometers for additional information.


Essentially, since moisture is required for incubating and hatching eggs, the water bottle allows water to pool in the base of the incubator.  One of the thermometers should have a cotton wick on it that goes down into the water, making it a “wet bulb” thermometer.  Humidity is the amount of water in the incubator that has evaporated in the air of the unit.  The wet bulb humidity reading on the thermometer is not the same as Relative Humidity (RH) in percentages.  Rather, it is the temperature of the water in the base of the unit.  When used in conjunction with the incubator temperature, you can find the RH by use of the chart in the Hatching Manual which can also be ordered separately—BG81-2.


For most fowl, the incubating temperature should be 99.5 to 100 degrees F.  The wet bulb temperature should be 84 to 86 degrees F.  The combination of these two readings is equivalent to approximately 51 to 56% Relative Humidity.

Different types of eggs require different settings for temp. and humidity.  The thermostat is adjustable and will be able to achieve a wide range of temperatures.


In almost all shipments, we have taken care of pre assembly to a certain point of completion.  Full assembly would require a much larger box, would cause damages, and be far more expensive.  There is a diagram in the instructions provided with the TX Incubators to show you how to put the pieces together and to attach the turning mechanism.  You may request Bulleting #161 for a preview.


Chicken or other fowl should be turned a minimum of 5 to 7 times a day if you don’t use the automatic turner and you will still be able to hatch a large percentage of eggs that are fertile.  We recommend using the automatic turner if you are away from the incubator for long periods of time.   The standard AT1 turner for this unit will turn the eggs once every hour, taking only 30 seconds or so to complete the turn.  We have also developed the AT3 turner which turns the eggs continuously, bet extremely slowly—it takes a full hour to make the same turn that the AT1 does in 30 seconds.

Many of the schools have purchased the AT3 as it is priced quite a bit lower than the AT1, but care should be taken that it would work in your particular breeding program.   Exotic bird breeders will develop their own patterns of turning frequency that best suits their type of eggs.


Imagine if you slept all night in the exact position you fell asleep.  Most of us would have some kind of circulation problem and/or soreness.  We turn ourselves while we sleep to relieve the pressure that restricts the nerves and impairs circulation.  Mother hens get off the nest and instinctively beak and turn the eggs at intervals.  This is necessary for the developing embryos to grow into healthy, vigorous chicks.  Any interval of turning longer than three or four hours gets declining results.  We recommend the turning should be 180 degrees and should be done in alternating directions.

Frequently Asked Questions on Grumbach Incubators

Thank you for choosing and entrusting Grumbach Incubators to incubate your valuable eggs. On receiving your incubator please un-pack it and make sure it is fitted with the features you ordered. Please check all rollers are present plus mercury thermometer and dial hygrometer. Fill in the guarantee card and the I.D.the serial number of your incubator is printed on the back cover of the incubator, send your card to your purchasing agent, all Grumbach incubators are guaranteed for twelve months from the time of purchase.

Both the B.S.S. and S84 range of incubators are similar in the operating procedures with operating ease and precision at the forefront of their design. It is a good idea to store the shipping crate and pallet in case the incubator requires shipping to us for an overhaul or service in future years.

Please ignore any operating instructions for features not fitted on your individual incubator.

Where to place your incubator ?

The site chosen for any incubator is vitally important for the optimum performance of the machine.

An incubator’s temperature control works at its optimum when its surrounding environment has a reasonably constant temperature. Grumbach incubators have great insulation properties, but large external variations in temperature will affect even these machines temperature control.  Do not place your incubator where direct sunlight falls on it, as this will increase the incubators temperature due to the ‘green house effect’.

As relative humidity can only be increased within the incubator, it is important that the room where the incubator is situated, has as low as possible ambient humidity. This will in turn give you a greater field of control on humidity settings within the incubator. Kitchens and bathrooms generally have high ambient humidity levels so should be avoided.

The surface where the incubator is placed, should be level to decrease the problem of ‘egg creep’ on the turning rollers. Make sure you have sufficient room to open the door fully to allow removal of the egg trays.

How to Operate the Temperature Control ?

Once your machine is sited, plug the Incubator into the outlet and turn on the main power switch. If digital readers are fitted these will light along with the power switch. Leave the incubator running for several hours to heat up and allow the internal temperature to stabilize. The ‘Thermo Light’ will be lit continuously while the incubator is heating up and will start to flash on/off as it reaches the set temperature. The temperature settings will be set either at or very close to 37.5° C in factory prior to shipment. The two knobs marked coarse and fine are your temperature controllers. The coarse knob should be used to adjust the temperature to “close to” the desired temperature and then the final adjustments made with the fine knob. Whenever making adjustments please ensure you check the temperature regularly, as the change does not reflect instantly.

Each incubator is fitted with two additional safety thermostats. On the left hand side panel a mechanical safety thermostat is fitted. This will stop your incubator from overheating if there was a failure with the electronic primary thermostat. This is preset at the factory and should not need altering.

A third electronic thermostat is fitted close to the fan housing. This is a safety feature and will stop any heater damage should the fan stop working. This is fitted under E.E.C. law and should not be tampered with.

How to Calibrate the Thermometers?

Each incubator comes with a laboratory high-grade mercury thermometer. These thermometers are very precise and we strongly advise that if you have a digital thermometer fitted to your machine, that you calibrate it to the same reading as the mercury thermometer. The thermometer fits into the bracket supplied on one of the turning trays and should be viewed straight on to see the blue mercury. Whenever cleaning the thermometer only use cold water.

Digital thermometers have a far quicker reaction time to small changes in temperature than mercury thermometers. Once the desired temperature is established within the incubator (set by the mercury) calibrate the digital unit to the same reading if required.

To calibrate simply remove the black plastic frame that surrounds the red plastic front, this comes off by mildly prying it with a knife or screwdriver, then remove the plastic front. Then simply use a screwdriver to turn the adjusting screw clockwise to turn the thermometer reading up or counter-clockwise to turn it down. (the calibrating screw is made of plastic so please be careful not to over-adjust, as it could damage easily.) Once the desired reading is achieved replace the front. This is safely achieved with the incubator turned on.

How to Set Up Auto Turning?

When setting up the turning tray with the rollers, make sure that the rollers are at right angles to each other. Simply count the number of spaces between rollers so each end of the rollers is the same number of slots apart from each other. The desired distance between rollers is dependant on the size of egg you are incubating. The egg should sit on the rollers with the bottom of the egg not touching the turning tray. To minimise ‘egg creep’ along the rollers it is best to alternate each egg so the top of one egg faces the front of the incubator and the next the back and so on. When placing the turning tray into the incubator make sure that the brass rod on the turning tray enters into the fork on the turning arm.

The auto turning will only work when the switch on the control panel is turned on and it lights up. To set the frequency and length of turn the timing clock on the side of the incubator will have to be set.

The 24-hour time clock has I digit per 15 minutes around the out side of the clock face. When one digit is pushed in this is equal to the turner moving for that period of time. 15 minutes of turning equals approximately half a stroke. For small eggs such as quail and partridge this is about a 180degree turn. For the larger eggs a full stroke (two digits pushed in) will be needed for each turning session. Please remember to start the turner at one side for larger eggs as if set off in the middle of its stroke each 30-minute turn will end back at the middle of the incubator. As a rule of thumb a chicken egg will need two digits in then the next four out (no turning) and so on around the clock. This will give you half an hour turning (one stroke) and one hour of no turning. But the frequency and amount of turning is down to your individual choice.

How to Set up the Humidity Control?

On incubators where the auto-Humidity feature is not fitted the humidity can be increased via filling the bottom tray with water. As relative humidity is directly proportional to the surface area of water, small receptacles may be placed on the floor of the incubator with different surface areas until the desired humidity level is obtained.

On auto-humidity incubators the reservoir should be filled using distilled water to combat lime scale build up within the reservoir.  Opening or closing the Humidity flap to various degrees can alter the humidity level to suit most incubation needs. If when the flap is fully open (white line is at three o’clock) the humidity is still not as high as you require then switch on the Humidity on/off switch. By turning the Humidity up/down switch this will increase the humidity level up to 100%. Once the on/ off switch is turned on there is a small heater situated under the water reservoir, which warms the water, and so assists in evaporation hence increasing the humidity level. The up/down switch is a simple thermostat that allows you control over how warm the water gets. By using this facility in conjunction with the flap, you can control the humidity level to your exact requirements

Make sure the water level is topped up this is easily viewed through the plastic filling tube. Whenever the incubator is not in use or is being moved, empty any water from the reservoir into a bowl by removing the drain plug at the base of the filling tube and tilt the incubator forward slightly.

To calibrate the dial humidity gauge, wrap it up in a damp cloth for 15 minutes. Then with a small screwdriver turn the pointer via the screw in the back off the gauge to 100%. Then leave for it to drop to ambient humidity level (generally between 30-50 %).

To calibrate the digital Hygrometer remove the front the same as the digital thermometer. The two calibration screws are found on the side of each digital digit.

Cool Down Timer

Cool down timers are only generally used when incubating waterfowl eggs the time clock is set the same as the turning/ timer, with each digit inserted equalling 15 minutes of no heat

Air vent

The air vent is a circular rose on the top front of the S84 incubator and a larger oblong grate on B.S.S. models. This allows you to manipulate how much fresh air enters the machine. For most eggs this will be left fully open, but some geese and other waterfowl eggs seem to require a slightly stale air environment, so the flap may be either partially or fully closed to suit your individual needs.

How to clean your incubator?

Each incubator has been designed for ease of cleaning. All surfaces can be cleaned with warm water and a mild disinfectant. Fumigation with Formaldehyde gas is recommended between hatches. Please do not place the rollers in a dishwasher as they will bend and distort. The filter gauze should be changed annually under normal conditions but under heavy use this will require a more frequent change.  A water-sanitising tablet may be used in the water reservoir.

Essential Spare parts

Grumbach incubators are built with reliability in mind. However over time certain parts may become warn and fail as with any other machine. This always seems to happen at the most inopportune moments and we strongly advise you to have a small number of spare parts to hand to get the incubator back up in use swiftly. These include a spare fan motor, turner motor, thermostat card and a few 3amp fuses.

A quick problem and answer guide.

Problem Probable cause or answer
Temperature fails to reach desired level.
  1. Fan failure
  2. Thermostat card failure
Discrepancy between mercury thermometer and digital thermometer        Calibrate Digital thermometer.
Turner not working
  1. Make sure turner is switched on, on control panel
  2. Make sure turning tray is engaged in turning are fork
  3. Make sure digits are pushed in on timer.
  4. Turner motor failure.
No power to incubator. 1. Check and change the two 3 amp fuses inside left side panel near where power cable enters the back of the incubator.Warning unplug power source before removing any panels2.  Make sure cool down timer is not engaged.

RX’S which one is for you?

Lyon Electric makes four (4) ROLL-X models of incubators:

The RX model has “wafer” temperature control only.

The RX1 model is fitted with a solid state circuit board with the single turn potentiometer.

Both models come with a fan for air circulation and even heat distribution, spirit alcohol thermometers and a top mounted water bottle for humidity control.  The wafer may require frequent adjustments and annual replacement, but they are very inexpensive and quite reliable.  These two models are primarily used by poultry and game bird breeders for incubating and hatching.

The RX2 models have both the wafer unit and the solid state circuit board temperature controls and you can choose from either the single turn or ten turn potentiometer.  Fan and mercury thermometers are standard features.  The side mounted water bottle makes it easier to move eggs in and out of the incubator to check for fertility, embryo growth, etc.

All four models have the option of automatic turning and one grid selection.

What is the purpose of the wafer unit?

Since the wafer is heat sensitive, it acts as on over-temperature control.  With the primary thermostat set at incubating temps 99.5° to 100° Fahrenheit , the wafer is set about 2 degrees higher, which gives you protection against “spikes” in temperature due to power fluctuations or outright failure of the solid state circuit board.

How do you know which control is being used?

If the brass wafer is in control, there will be an audible “click” when the micro switch under the wafer closes and opens the circuit.  When the solid sate circuit board is in control you will not hear a click.  The indicator light on the circuit board will be in operation regardless of which control is in use.

Who would use either of the RX2 models?

Many units are in use at Universities, bio-medical research facilities and with breeders of parrots and other avian breeders, as well as poultry breeders who prefer the dual temperature controls.  Especially attractive is the side-mounted water bottle which holds more than twice the amount of water and reduces spills into the base.

How is the humidity control accomplished?

The water bottle can be adjusted higher or lower to increase or decrease the humidity.  You regulate the humidity by the quantity of water allowed to flow into the base of the incubator.  The heat in the incubator warms the water and creates evaporation.  Monitor the “Wet bulb” temperature reading.

How are the eggs turned?

In the Roll-X model incubators, your size of egg determines the grid selection.  When placed in the base unit, the bottom of the grid remains stationary and the top section slides back and forth.  The eggs are set in vertically between the square openings of the grid, with the air cell upwards.  The automatic turner has a pull rod which attaches to the top section of the grid.  When the; motor is activated the pull rod makes the top of the grid slide to the left and then right with an hour rest in between.  If you put your elbow on a table and pretend to arm-wrestle with your fist on a vertical position – start about halfway tilted to the left at 45° degrees and then move your arm to about halfway over on the right another 45° degrees, giving your eggs 90° degrees of turning once every hour.  Lyon also provides a pull rod for manual egg turning, and you can do it as often as your needs dictate.

How does the Roll-X convert to a Hatcher?

Remove the grid from the base unit and unplug the turner – pace the eggs onto the flat surface of the screen in the bottom of the base.   Remember to lower the temperature at this time and to raise the humidity.  Many people will have 2 units – one for just incubation and another for just hatching.