What is the maximum/minimum pressure/temperature at which Danfoss switches can be set?
Answer: Danfoss manufactures various pressure switches which can have a setting range of anywhere between -1 to 400 bar and temperature switches from -60 to +300°C.
However, each switch will have its own regulation range as detailed within the product catalogue pages. It is always good practice to avoid choosing a product which will be switching near to the limits of its range.
What is the DIN numbering of terminals?
Answer: Terminal numbers are always ODD for inputs & EVEN for outputs, which explains why the changeover switch in almost all pressure & temperature switches has numbers 1, 2 & 4. The live feed goes in at 1. It comes out at 2 when the pressure or temperature is low (so take this to your pump or heater as a live feed) out of 4 when the temperature or pressure is high. (You can take terminal 4 to a ''satisfied'' tell-tale lamp or to an unloading valve or cooling fan, if you wish).
What is differential?
Answer: The differential is the difference between a switch cutting in and cutting out – it is like on a kettle after it has boiled and switched off, you can not switch it on again until the kettle has cooled down a little. Too small a differential will give rise to short running periods with a risk of hunting. Too high a differential will result in too large pressure or temperature oscillations.
How can the differential in RT controls be adjusted?
Answer: To set a differential in RT unit, please use the diagram that can be found in customer instruction. The diagram shows which digit should be set at the differential setting disc to obtain required differential. The input to the diagram is differential range and neutral zone, which gives the setting position on the setting disc.
How can I characterize vapour charge in the sensor of the temperature switch?
How I can characterize adsorption charge in the sensor of the temperature switch?
Answer: The sensor is partially filled with carbon particles, and the rest of the element contains superheated gas, normally CO2. Reaction is always in the sensor and working point will vary with the ambient temperature.
After installing the switch and making the setting based on scale values, the real system pressure value and scale value seem not to correspond. What is the reason?
What is the time constant in relation to temperature switches?
I am looking for the on/off switch with the highest possible IP protection, what options do I have?
How does the manual reset work in relation to on/off switches?
What is differential setting (pressure or temperature)?
What does SPDT stands for?
What is the most common contact system type used in Danfoss switches?
What would be the best pressure switch choice for applications requiring high repeatability, accuracy and adjustable differential?
When is it recommended to use a gold-plated contact system?
How can I improve the heat transfer if I use a sensor pocket with a temperature switch?
Where I can find technical information regarding on/off switches?
Do I need an external power supply for RT switches?
Can I buy the sensor of a RT temperature switch as a spare part?
Is there any way to tell if charge is lost in a temperature switch?
Is it possible to recognize if a RT has "double" bellows installed, from just looking at it from outside?
Do Danfoss temperature switches come with sensor pocket included?
How do I maximize response time of a temperature switch?
Answer: First, the sensor should be immersed in the media with biggest possible surface. If this is not possible and a sensor pocket is needed, remember that the additional thermal inertia of the pocket will play a significant role. You can use heat conductive paste to reduce it.
What do I do if I need very quick reaction to changing temperature?
Answer: In case of any mechanical switch with charge sensor, the reaction time will always be a considerable factor. The solution could be using a temperature sensor, which has much smaller themal inertia.
What is the response time of Danfoss temperature switches?
Answer: There is no exact data on the time constant for temperature switches in particular - it largely depends on sensor charge, way of mounting (contact to media), temperature changing speed, ambient temperature and other factors.
Which temperature switch should I use to control the area temperature in an engine room?
Which switches should I use for seawater - or other media with particles or depositions?
Answer: In case of seawater you should generally use diaphragm versions of switches:
- KPS 43, 45 & 47
- CAS 143, 145 & 147
- MBC 5100 with diaphragms
Seawater may contain contamination and certainly salt, both of which will likely accumulate inside the application. Not least inside the switch,, because the water inside is almost still (no flow). If salt crystallizes on the bellows surface it can easily affect its proper function.
In case of diaphragms, very smooth and flexible, this problem is less visible. This will cause the depositions to be removed from its surface, and until the whole system is filled and blocked with depositions, it will work.
Depositions are especially dangerous when you have a small bellows - like in MBCs.
If you need to use bellows version of switches then try to choose comparatively big bellows - surfaces on which depositions are stored are comparatively far away and it would take a longer time before they affect bellows function. RT is a switch of this kind.
Where do I find production date on pressure or temperature switches?