Welcome to Instromet Weather Systems' new service page. Here we will be compiling known symptoms to look out for on our legacy products. We shall endeavour to offer tips for investigating and resolving common problems which may arise from these ageing products.
Of course, if nothing on this page covers the symptoms you are experiencing, then please contact us directly in the normal way to arrange a service here at our North Walsham workshop. Contact Instromet.........
Should you require a workshop service, we do insist that any display returned to us for servicing be packaged correctly. Unfortunately, from time to time, we do have units arrive with insufficent packaging. We have even received a display here before in nothing more than a jiffy bag! Unfortunately, insufficent packaging can result in the below occurring:
Temperature displayTemperature reading displays "LLLc":
This is probably one of our most common calls we take regarding temperature related problems.
A display which shows "LLLc" generally indicates that the display has lost contact with the temperature probe. When this occurs, we normally recommend checking all connections to the temperature sensor on the 'green' and 'white' wires. Even cutting the cabling back a little and re-connecting with fresh cable is a good idea.
One cause of this on older units (pre 2004 generally) is that the wind sensor terminal block may have corroded due to originally being made from mild steel. This was changed shortly after 2004 to a stainless version which shouldn't suffer from this problem.
Once the cable has been checked and re-worked if need be, we would suggest powering the system down and removing the back up battery for a couple of minutes. We suggest this as sometimes the temperature display will 'lock up' rather than burst into life. Hopefully once power is then re-established, all should be ok.
If the display still shows "LLLc" then it may be a good idea to test the temperature probe itself. The below link gives the expected resistance measurements per temperature degree. When testing the probe, it is important to disconnect it from the rest of the system or any ohmmeter will meaure the internal resistance of the rest of the system and give a false reading: Temperature probe readings........
But it would be very rare for the "LLLc" to actually be caused by a display itself. cabling and connections are the normal way to go on solving this problem.
Temperature display stuck on one reading no matter what is pressed:
Carrying on with the temperature theme is this next issue of a temperature display being "locked" on one temperature with buttons having no effect.
This problem is normally caused by a low or exhausted back up battery within the display. This being the case we recomend removing the rear panel of the display via the four screws (ensuring the display is powered down firstly at the mains). Once the back panel is removed it should be possibly to see within the display the temperature display back up battery. This will either be a double or triple "A" battery.
If this battery hasn't been replaced for some time it could be possible that the battery has leaked and damaged the battery holder. If this has occurred then the display may need returning to us for a new holder to be fitted.
But hopefully once the battery has been replaced, the temperature display should, all being well, operate correctly once more. If it doesn't come back on then the temperature display may need replacing. If this is the case, then it would be best to contact us to arrange workshop service.
Firstly we'll endeavour to identify the three rain sensor builds which have been supplied:
Instromet over the years has supplied three rainfall sensors shown above. The left most sensor is the original R&D Electronics supplied unit. This then changed over to the centre version, supplied mainly by Instromet while part of the Novomec group under part number 480 1000 040/01. When the supplier of the funnel section ceased to trade, Instromet decided to take over the production of the entire sensor and had moulds of the funnel sections produced. This of course meant that Instromet now has full control over the sensor build and the right hand unit is still the current build, available under part number 480 1000 121/01. Although the funnel design and circuit layouts have changed over the years, each sensor is in reality one and the same, all operating from the same electronics and same specification. This means that all rainfall sensors supplied by Instromet are backwards compatible.
The Instromet rainfall sensor operates in the following manor: Rainfall is collected via the 80mm funnel, this rainfall then passes through a pair of filters before dripping through an internal infra red beam at the exit of the funnel. Breaking this beam will cause the sensor to produce a pulse output in the region of 5v DC per droplet. Once the water passes through the beam, it then exits the bottom of the sensor. When working correctly the sensor will produce 100 droplets of water per 1mm of rainfall (Accuracy +/- 5%). This can be tested by applying 5ml of water into the funnel manually. This should then produce 1mm (+/- 5%) of rainfall on the wall display.
Now like any rainfall sensor, the Instromet version does unfortunately require regular maintenace to allow it to function both correctly and accurately. This mainly involves cleaning the filters at the base of the funnel. Its important to keep these filters clean as not only do they prevent debris from blocking the 1mm hole at the base of the funnel, but the also help to regulate the water flow rate through the sensor. Removing them will cause water to trickle through the sensor rather than drip, and in doing so will give a reading lower than expected. Its also important to clean the 1mm hole at the base of the funnel from time to time also, as this will slowly close up due to algae etc. A piece of fine wire should be sufficent for this job.
Now moving on to actual problems with the rainfall sensor, theres only really one problem that will be encountered....No count on the display etc, ie no output. Of course this can be caused by a few different problems, so we'll endaevour to cover the main ones below:
Broken cable: With any cable in an outdoor enviroment, it can be prone to deteriation over a long period of time. Also being outside, damage can be caused by DIY / Gardening jobs / Wildlife etc. So always check the integrity and continuity of the cable in the first instance. One actual electrical test can be performed at the sensor end. Unplug the sensor from the three way connector, then using a paperclip, short the red connection to the yellow. Doing so should induce a count of 0.01mm on the display every time the two are touched together. This will at least indicate that a) the red and yellow cables are ok and b) the sensor is receiving its power supply on the red wire.
Internal debris: The next thing to check for would be internal bedris. Yes internal debris! Although the sensor has filters at the base of the funnel, we have known spiders and other little criters to enter the water exit hole and build nests/webs inside the sensor. These can either disrupt the infra red beam or divert the water droplet from the beam, so always check for unwanted visitors!
Signs of corrosion: Now although the PCBs within the rainfall sensors are conformally coated to protect them from water ingress, the infra red devices and three way connectrs are not. If they were the device simply wouldn't work. This being the case, check around these devices for signs of corrosion, ie brown patches similar to rust on a car. If signs of corrsion are evident them the PCB will require replacing. Of course if the sensor is routinely maintained then hopefully this should be less of a problem, but with any device which allows water to pass through it, this will always be a possibility.
Break the beam manually: So after checking the cable, looking for spiders and signs of corrosion, the sensor still isn't working, try breaking the infra red beam manually. Try not to do this in direct sunlight as the sunlight will upset the infra red beam, but if breaking the beam with say a pen doesn't induce a display count, then the most likely cause will be an electronic failure of the sensor PCB. This being the case its probably best to contact Instromet for advice.
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