Otter Switch for Fan
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- richardpope50
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- Location: Horsham, West Sussex
Otter Switch for Fan
I have an otter switch in a swirl pot to switch on a fan at 96 degrees then off at 91 degrees - standard RV8 part. Despite this being a new one, my circuit is not working.
As the switch had two terminals I assumed it was an earth switch so when it reached 96 degrees it would eath (in may case, a fan relay) and fan turned on. However it doesn't. (My wiring circuit is OK, by the way.)
Do I assume I have misunderstood the wiring? If so, how should it be wired, please.
As the switch had two terminals I assumed it was an earth switch so when it reached 96 degrees it would eath (in may case, a fan relay) and fan turned on. However it doesn't. (My wiring circuit is OK, by the way.)
Do I assume I have misunderstood the wiring? If so, how should it be wired, please.
Richard.
Dax Rush 5.0l TVR V8, EFI with Megasquirt ECU and wasted spark, Racelogic Traction Control and Quaife LSD ....... Now nut and bolt restoring a TR6
Dax Rush 5.0l TVR V8, EFI with Megasquirt ECU and wasted spark, Racelogic Traction Control and Quaife LSD ....... Now nut and bolt restoring a TR6
they are a straight switch as in when they make the two terminals are joined together. It could work the way you want but you will have to connect one terminal to earth and the other to the - of your relay coil or you could use it to switch the + to your relay as in battery-fuse-otter-from otter-relay +. Whichever way suits you best. Otter switches are capable of running a fan without a relay by the way but putting a relay in will help it last a bit longer.
- richardpope50
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- Joined: Thu Jan 28, 2010 12:25 pm
- Location: Horsham, West Sussex
That's what I did but it does not work. This is the second switch. The first I checked in boiling water and it did not make a circuit between terminals so bought another one thinking it was duff. I have not tested the new one in water but it's not working either.katanaman wrote:...you will have to connect one terminal to earth and the other to the - of your relay coil ...
When I bypass the switch and connect the two terminals together the fan comes on.
I'm really puzzled.
Richard.
Dax Rush 5.0l TVR V8, EFI with Megasquirt ECU and wasted spark, Racelogic Traction Control and Quaife LSD ....... Now nut and bolt restoring a TR6
Dax Rush 5.0l TVR V8, EFI with Megasquirt ECU and wasted spark, Racelogic Traction Control and Quaife LSD ....... Now nut and bolt restoring a TR6
- richardpope50
- Gold Member
- Posts: 616
- Joined: Thu Jan 28, 2010 12:25 pm
- Location: Horsham, West Sussex
That's what I did but it does not work. This is the second switch. The first I checked in boiling water and it did not make a circuit between terminals so bought another one thinking it was duff. I have not tested the new one in water but it's not working either.katanaman wrote:...you will have to connect one terminal to earth and the other to the - of your relay coil ...
When I bypass the switch and connect the two terminals together the fan comes on.
I'm really puzzled.
Richard.
Dax Rush 5.0l TVR V8, EFI with Megasquirt ECU and wasted spark, Racelogic Traction Control and Quaife LSD ....... Now nut and bolt restoring a TR6
Dax Rush 5.0l TVR V8, EFI with Megasquirt ECU and wasted spark, Racelogic Traction Control and Quaife LSD ....... Now nut and bolt restoring a TR6
- Ian Anderson
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- Location: Edinburgh
Where in your circuit is the switch located?
If it is in the section from engine to radiator switch is in water you should get the fans running
If it is from the outlet of the rad back to engine your switching temperature is too high. The water coming out the rad will be closer to 65 - 70 degrees on a good system.
I run a switch on the outlet of the radiator and used a ford part - cannot remember off hand which number but they have 3 set at different temperatures.
On the radiator outlet you will see less fluctuation in water temp and hence the fans will not switch on as often as on the engine outlet side.
Ian
If it is in the section from engine to radiator switch is in water you should get the fans running
If it is from the outlet of the rad back to engine your switching temperature is too high. The water coming out the rad will be closer to 65 - 70 degrees on a good system.
I run a switch on the outlet of the radiator and used a ford part - cannot remember off hand which number but they have 3 set at different temperatures.
On the radiator outlet you will see less fluctuation in water temp and hence the fans will not switch on as often as on the engine outlet side.
Ian
Owner of an "On the Road" GT40 Replica by DAX powered by 3.9Hotwre Efi, worked over by DJ Motors. EFi Working but still does some kangaroo at low revs (Damn the speed limits) In to paint shop 18/03/08.
Is it rated highly enough to turn a fan on? The otter switch I am thinking of (which sits in the inlet manifold of a P6 just behind the thermostat) is for turning on the 'push in the choke' light, and would vapourise if you tried to switch 30Amps for an electric fan.....
Chris.
Chris.
--
Series IIA 4.6 V8
R/R P38 4.6 V8
R/R L405 4.4 SDV8
Series IIA 4.6 V8
R/R P38 4.6 V8
R/R L405 4.4 SDV8
Richard!
Why would you use an otter switch in a swirl pot? This will surley see the sensing end seeing a mix of air and water?? Have I got that right??
As previously said, The otter switch is a pair of normally open contacts. So you can wire a + feed to the + side of the relay and wire the - side of the relay coil to one side of the otter switch with the other side going to earth which will close the relay. Or run the + feed to the otter switch to feed the + side of the relay to make it work as long as the - connection of the realy is grounded properly.
I ditched my otter switch and fitted an inline temp sensor in my top hose to trigger the fan relay on my MGB V8.
Are you sure the fans are working ok ??
Why would you use an otter switch in a swirl pot? This will surley see the sensing end seeing a mix of air and water?? Have I got that right??
As previously said, The otter switch is a pair of normally open contacts. So you can wire a + feed to the + side of the relay and wire the - side of the relay coil to one side of the otter switch with the other side going to earth which will close the relay. Or run the + feed to the otter switch to feed the + side of the relay to make it work as long as the - connection of the realy is grounded properly.
I ditched my otter switch and fitted an inline temp sensor in my top hose to trigger the fan relay on my MGB V8.
Are you sure the fans are working ok ??
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
- Ian Anderson
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Last thought
Is the "circuit" made between one of the terminals and the houusing of the unit?
I you have used ptfe tape you may not have a good "earth"
Ian
Is the "circuit" made between one of the terminals and the houusing of the unit?
I you have used ptfe tape you may not have a good "earth"
Ian
Owner of an "On the Road" GT40 Replica by DAX powered by 3.9Hotwre Efi, worked over by DJ Motors. EFi Working but still does some kangaroo at low revs (Damn the speed limits) In to paint shop 18/03/08.
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- richardpope50
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- Joined: Thu Jan 28, 2010 12:25 pm
- Location: Horsham, West Sussex
I've just seen that my long reply to you guys is not here. It was, I'm sure so sorry if you have not seen it.
Summary is that swirl pot from donor engine (TVR Griffiths) with Rover Otter switch in it. Plenty of water in swirl pot and circuit goes ign +ve to relay then relay -ve to Otter switch terminal then other terminal to bolted earth. When I bridge the two otter switch terminals, all works fine.
Otter switch is fitted using PTFE tape but swirl pot bolted direct to a chassis mounted plate so earth there.
My old Otter switch did not appear to work so got a replacement from Clevour Trevor as a TVR Griffiths stock part.
I'm going to have to check this new one in boiling water, I guess. Just got through IVA (see other post) so now chance to check things out.
I think my (TVR (CAI)) temp gauge is incorrectly showing temp. I'd got it to 105 degrees on dial but wondering how correct that is.
Summary is that swirl pot from donor engine (TVR Griffiths) with Rover Otter switch in it. Plenty of water in swirl pot and circuit goes ign +ve to relay then relay -ve to Otter switch terminal then other terminal to bolted earth. When I bridge the two otter switch terminals, all works fine.
Otter switch is fitted using PTFE tape but swirl pot bolted direct to a chassis mounted plate so earth there.
My old Otter switch did not appear to work so got a replacement from Clevour Trevor as a TVR Griffiths stock part.
I'm going to have to check this new one in boiling water, I guess. Just got through IVA (see other post) so now chance to check things out.
I think my (TVR (CAI)) temp gauge is incorrectly showing temp. I'd got it to 105 degrees on dial but wondering how correct that is.
Richard.
Dax Rush 5.0l TVR V8, EFI with Megasquirt ECU and wasted spark, Racelogic Traction Control and Quaife LSD ....... Now nut and bolt restoring a TR6
Dax Rush 5.0l TVR V8, EFI with Megasquirt ECU and wasted spark, Racelogic Traction Control and Quaife LSD ....... Now nut and bolt restoring a TR6
If you bridge the switch and all works then the internal conact isnt closing for some reason.
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
Just use an otter switch like the TVR, you will need to connect both of the spade terminals to complete a circuit.
Popular ones are Interpart 50250: 86-76C
The switch is in the bottom of the swirl tank & the tanks intended purpose is to separate air out of the coolant (mainly because the rad is relatively low)
Popular ones are Interpart 50250: 86-76C
The switch is in the bottom of the swirl tank & the tanks intended purpose is to separate air out of the coolant (mainly because the rad is relatively low)
Dave