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Manual override fo Kenlowe Fan


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I have a Kenlowe fan that is operated by a thermostatic switch installed in the hose between engine and bottom hose of radiator (as sold by Moss)

 

I wish to fit an underdash manual override switch with warning light to advise when the fan is running. Some of you may say "why? when the fan cuts in or out as required automatically" Well, it's all for peace of mind really.

 

Anyways, does anyone have a schematic diagram of the wiring required to achieve this? I understand that I may have to fit a relay?

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Hi Lindatr4, as per Neil's diagram all you need to do is effectively put a switch between the two terminals that the thermostatic switch connect to, to provide a manual by pass. You should already have a relay in your set-up ideally. And the earth on the switch will be to provide an earth to the lamp inside, be careful to connect the terminals the right way around on this type of switch otherwise you might have the lamp on all the time

 

Mark

Edited by MRG1965
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Thanks guys for your valuable advice. It transpires that the present setup does not have a relay (oops!) I tend to think that the original installation of the Kenlowe was too simple for its own good. A live feed from the fusebox to the fan, through the inhose thermostatic switch and then to earth. It worked but it cannot be good can it? I understand that these fans can pull 25 amps on start up.....My plan is to fit a 30 amp relay as per Neil's diagram but what gauge/ colour cable is best for this application. I am thinking 3 or maybe even 4 mm?

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Hi Linda

 

The same link above does cable. http://www.vehicle-wiring-products.eu/product.php/1021/28-0-30mm-2mmsq-17-5-amp

 

Usually Brown as a 12V supply But I tend to use red and Black for the earth return.

You could use the cable in the link or the next size up.

The fan will take about 25amps for a few seconds and then go back to 10amps(ish) .

 

You may need some terminals also -

http://www.vehicle-wiring-products.eu/section.php/72/1/non-insulated-terminals

 

Roger

Edited by RogerH
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Hi Andy,

having the sensor in the top hose works OK but sealing can be interesting but can be done.

Have the sensor in the bottom hose (metal down pipe) is a neat and tidy way of doing things and shouldn't ever leak.

 

Simply adjust the thermostat to compensate for position.

 

Roger

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A number of the usual suppliers can sell you the metal pipe, which carries the coolant from the bottom of the radiator back to the pump, with a built-in boss for a thermostatic switch, which they can supply, of course. This is very convenient and overcomes the problem of weeping from whichever hose connection might be used.

 

As Roger has mentioned, a relay should be used in order to avoid a hefty current being switched by the thermostat - should the contacts get damaged over time, it's far easier to swap a relay than the thermostat.

 

The original 1970 Kenlowe offering included a little metal bracket, which could be attached to the underside of the dashboard. The bracket housed a manual over-ride switch and a lamp which indicated that power was being fed to the fan (which, therefore, should be running!).

 

Ian Cornish

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LNK has a thermo switch in the downpipe. However, in addition to being a safe guard for overriding a failed switch it can also be used to avoid heat soak

 

Switch it on manual just as you join a stationary queue of traffic and it will hold the heat soak at bay and avoid a temp spike as it tries to handle peak temp without normal airflow

 

NB: Not a lover of the 'kenlow' switch so used the existing rheostat switch hole, much nicer (IMHO) :ph34r:

 

DSC_1731.JPG

Edited by North London Mike
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I bought my fan from Kenlowe and came wth a wide thick rubber band which slipped over the radiator tope hose inlett. This band had a groove in it which the capillary tube to the sensor bulb was laid in. The hose is then slipped over it as per normal with the hose clip tightened directly over the band. No leaks or weeps so far and have had it apart a couple of times dealing with thermostat issues. I did wonder if the sensor bulb would restrict water flow as it sits in the radiator inlet but doesn't seem to. Thoughts?

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Although I used to have one like Andy's (bulb in the rad inlet, etc.) - which also never leaked, FWIW - the Kenlowe I bought a few years ago has a small rod-like sensor which sits between a couple of the radiator fins, completely outside of the actual cooling system.

 

It seems to work well (although I also seem to be able to "kill" the Kenlowe brains relatively often - I'm on my third in about 6 years and I think it's just died again...).

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LNK has a thermo switch in the downpipe. However, in addition to being a safe guard for overriding a failed switch it can also be used to avoid heat soak

 

Switch it on manual just as you join a stationary queue of traffic and it will hold the heat soak at bay and avoid a temp spike as it tries to handle peak temp without normal airflow

 

NB: Not a lover of the 'kenlow' switch so used the existing rheostat switch hole, much nicer (IMHO) :ph34r:

 

DSC_1731.JPG

hi Mike, I have one of the pipes in my garage ready to fit, but am unsure which of the sensors to fit. I have looked at the moss site and they sell about 5 different sensors all with a different on/off range. Can I ask which ond you chose to fit and if the override gets used much. This morning spookily I was planning to use my infra red temperature toy (from maplins) to see what the temperature of the original metal pipe is at various gauge readings to see what sensor would be the best compromise. Also plan on the manual switch (you never know). But I'd also like you opinion as you have done it already.

 

Mark

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Hi Mark,

when determining what temp range you need for the thermostat you must also consider the thermostat in the top housing that controls water flow.

I use a Summer stat (76'C) in the Summer ( :blink: ) and a winter stat 82'C in the winter.

So an in pipe stat would need to come on after 82' and go off some where lower than 82'.

 

The complication comes in that the rad down pipe may/will run cooler than the top housing.

However generally the rad fan is required when the car is stationary. After a few minutes the rad stops cooling so the down pipe gets as warm/hot as the rest of the system.

It will cool quicker once on the move.

 

I think I have the 86 on/ 81 off http://www.moss-europe.co.uk/Shop/ViewProducts.aspx?PlateIndexID=7805

 

Roger

Edited by RogerH
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Hi Mark,

when determining what temp range you need for the thermostat you must also consider the thermostat in the top housing that controls water flow.

I use a Summer stat (76'C) in the Summer ( :blink: ) and a winter stat 82'C in the winter.

So an in pipe stat would need to come on after 82' and go off some where lower than 82'.

 

The complication comes in that the rad down pipe may/will run cooler than the top housing.

However generally the rad fan is required when the car is stationary. After a few minutes the rad stops cooling so the down pipe gets as warm/hot as the rest of the system.

It will cool quicker once on the move.

 

I think I have the 86 on/ 81 off http://www.moss-europe.co.uk/Shop/ViewProducts.aspx?PlateIndexID=7805

 

Cheers Roger. Had over looked the stat in the setup (dohhh, as Hommer would say).

 

Mark

 

Roger

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Although I used to have one like Andy's (bulb in the rad inlet, etc.) - which also never leaked, FWIW - the Kenlowe I bought a few years ago has a small rod-like sensor which sits between a couple of the radiator fins, completely outside of the actual cooling system.

 

It seems to work well (although I also seem to be able to "kill" the Kenlowe brains relatively often - I'm on my third in about 6 years and I think it's just died again...).

Tim I had the same problem with that type of sensor in a customers car, it went through 3 before Kenlowe Tech department admitted that they didnt think the electronics would stand up to the vibrations in a TR 4 cylinder engine bay. They sent me a Standard capillary bulb type which has run happily ever since.for the last ten years and umpteen thousand miles.

Stuart.

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Thanks all. Had a play with the infrared temp tester and the downpipe got up to around 90 degrees at a point I'd like the temp gauge never to get to. So looks like 86 on is the one for me. But they are not that expensive so i can suck it and see.

 

 

Thanks

Mark

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