Rain switch bypass

jsandekJuly 6, 2006

I have a Toro timer (Custom Command 18-station)with a Irritrol rain detector/switch. The system worked fine last year. This year, however, the system ignores the fact that the Irritrol transmitter/receiver are activated by rain. The owners manual that came with the Toro timer is useless. It does describe a "bypass" wire that the device is shipped with. The rain switch takes the place of this bypass wire. From reading the Toro owner's manual it appears that in the absence of a rain switch the bypass wire needs to be in place for it to work. Would I be correct in assuming that the rain switch functions like the bypass wire (under dry conditions)? That when it rains the switch opens-deactivating the circuit? If so my problem is the irritrol device and not my toro timer? Could this be verified by testing teh Irritrol sitch with an ohm meter?


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Yes, the by-pass wire is equilivent (electrically) to the rain switch. The by-pass wire is just a jumper; a short piece of solid core wire connecting two terminal points. The terminal block on the output board (upper right side) is marked by-pass. You can check the rain detector with a multi meter. Remember the rain sensor is adjustable. You may need to adjust it to respond to different levels of rain.

    Bookmark   July 6, 2006 at 10:48PM
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Thanks GardenGuy. I am aware of the adjustment on the irritrol rain detector/transmitter (outside my house). The Irritrol wireless receiver (wired to my timer) lights up appropriately (green power light on; green signal light on; red rain light on during precipitation). The Irritrol reciever does have a "smart bypass" switch--I think this a manual switch to activate the rain delay--even if it's not raining? What sort of electrical signal should I be able to detect using an ohm meter? If I disconnect the 2 red wires from the rain switch which are currently connected to the jumper terminals, should I be able to detect -/+ continuity depending on dry versus wet?

Many Thanks

    Bookmark   July 7, 2006 at 10:13AM
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You can test the rain switch using an Ohm meter. The red wires should be connected to the two 24 vac power terminals, keep them connected. Disconnect the brown and the white wires from the two sensor terminals, these are the switching wires. When the switch is not activated you should have a SHORT condition across those two wires. When the switch is activated, you should read an OPEN condition across those two wires. If it is switching, the problem is the timer, if not the problem is the rain switch. Keep in mind that the Custom Command will override the rain switch in a MANUAL start, also make sure that the Rain Switch Bypass Switch is in the ACTIVE position.

    Bookmark   July 15, 2006 at 10:39AM
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