Switch to override Heki 4 rain sensor (1 Viewer)

[Adrianlle]

Morning. First post in this section so forgive me if its all old hat! I have a Westfalia James Cook ( fantastic van) with a Heki 4 with a Heki rain sensor that closes the vent if it detects moisture. V useful but it can be over sensitive and close the roof when eg boiling pasta and at night when just dew. Has been a pain these hot nights when want to keep the vent open all night. So picked up from the James Cook German forum a straightforward mod for an override switch. If anyone thinks that might be useful to them , then say so and Iwill post full instructions and where I got the cheap bits to do it. Cheers.

 

[Armytwowheels]

Hi

I would be interesting in the info. We have two fantastic-vent one is super sensitive and the other, older one, is not a problem and will only close when raining properly. The newer one only has to hear a drop of rain and it shuts.

 

[Northernraider]

Yes definately as I've had to resort to removing the fuse from mine to stop it closing when I'm cooking or for some reason around 9.30pm each evening

It obviously detects a change in the atmosphere once the sun goes down.

 

[Adrianlle]

Ok- here goes from memory. Turn off the power to the Heki. Then first of all remove the inner panel of the Heki 4. Mine was screwed to the outer frame with about 15 screws. To find the screw heads unclip the lamp covers and the other covers. Remove the Lamp tubes. With the inner frame removed you will see a control box- mine was in the right hand corner facing forwards. If you look at the control box you will see what looks like telephone cable going into it with telephone like plugs. Identify the cable coming from the rain sensor. On mine, facing backwards, the cable ran down the left hand side of the Heki and plugged into the right hand side of the control box.
Unclip the cable from the box. It is in fact a telephone plug- an rj10. So just depress the raised bit on the top of the plug and remove it.
You will now need a length of rj11 cable prefitted with rj11 male plugs. You will need twice the distance between the control box and wherever you put your switch- see below. Cable from eBay for a few quid. You will also then need 2 couplers. One with an rj10 male plug at one end and an rj11 female at the other. A second coupler with an rj10 female at one end and an rj11 female at the other. I got them from run-IT-direct. Then take the first coupler above and click rj10 male into control box. Then the other coupler and click in the rj10 plug from the sensor. Then click in the new rj 11 cable between the couplers.
You now have a full circuit again between the sensor and the control box. What you now have to do is break into that circuit with a switch. I managed to position the switch handy for the bed. Find your own place for it and in such a way that the new rj11 cable from the control box to the switch is hidden. That was tricky but I managed it with the aid of a cheap fibre wire puller from eBay.
Take the mid point of the rj11 cable so that you form a loop and take that mid point of the loop to where the switch will be. ie each end of the cable is still clicked into the couplers. You now need to gently cut open the sheath of the rj11. cable at the mid point of the loop. It is easy to do with a Stanley knife. Inside the sheath will be 4 parallel thin wires. Lift out the middle 2 and cut one of them. Let’s call one wire A and the other B and the section coming from the Control box via the coupler A1 and the other half from the sensor A2. Fit terminals to the end of A1 and A2 and connect to an on/off switch. What you have now done is put a switch in the circuit for the sensing part of the rain sensor.The middle 2 wires form that circuit so with the switch on the sensor works as usual. With the switch off the sensor is isolated. Put the power back on and it should work. It did for me.
I then went one stage further and used a 3 position switch. So that 1 was sensor on as usual. 2 was sensor off. 3 closes the vent - this avoids having to stand with the close button on the remote control held down until closure. With my switch you just flick it to position 3 and it closes. To wire that up connect the A1 terminal above to the middle terminal of the switch and the A2 terminal to Position 1 terminal. That gives you sensing in Position 1 and no sensing in middle Position 2. Then cut wire B and connect both ends to a termInal that then connects to Position 3 on the switch. Thus the circuit is still made for sensing in Position 1 because both ends of the wire B are joined. But when the switch is clicked to position 3 the rain sensor is short circuited and the control box reads the new circuit as “ rain “ so closes the vent. If it doesn’t work then swap over the terminals to Position 1 and the middle. I think I may have had to do that. I find I use Position 3 all the time now for closing the vent rather than fiddling with the remote.

Then reassemble after testing. It all sounds rather complicated but in fact takes a few hours at most. The hardest bit for me was positioning the switch and running a hidden cable. I suppose if that’s not possible then a discreet on/off switch could be mounted on the face of the Heki inner casing itself.

It all worked for me with no issues and I substantially cribbed it from the James Cook German forum where it worked for others. But of course do it at your own risk! Hope this helps solve an irritating deficiency. Adrian

 

[Deadhead900]

Morning. First post in this section so forgive me if its all old hat! I have a Westfalia James Cook ( fantastic van) with a Heki 4 with a Heki rain sensor that closes the vent if it detects moisture. V useful but it can be over sensitive and close the roof when eg boiling pasta and at night when just dew. Has been a pain these hot nights when want to keep the vent open all night. So picked up from the James Cook German forum a straightforward mod for an override switch. If anyone thinks that might be useful to them , then say so and Iwill post full instructions and where I got the cheap bits to do it. Cheers.

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[Deadhead900]

Good post am going to have a go at it. very loud at 3am! If i can work out what bits do what. An open/ close switch would be good.