Thermostatic Radiator Switch
Thermostatic Radiator Switch
Author
Discussion

wherzmespana

Original Poster:

52 posts

233 months

Monday 2nd February 2009
quotequote all
Sorry for the boring topic, but does anyone know a source of thermostatic radiator fan switches - M22 87-90 degrees C? The one in my rad has had it and I am struggling to find one short of wading through pages and pages of them in my local Unipart. Thanks for any help!

Steve_D

13,802 posts

287 months

Monday 2nd February 2009
quotequote all
I gave up on mine after the third one failed. Don't know why they fail as the circuit runs through a relay.
Like you suggested I worked my way through the catalogue at my local factors for a replacement so it is nothing to do with the make the factory supply.

Finally fitted a Kenlow adjustable one which works great and I'm able to set it just where I want it.

Steve

spatz

1,783 posts

215 months

Tuesday 3rd February 2009
quotequote all
a relay is still an inductive load which can cause contact burn in any contact.
There is a thing called a relay diode that is used in parallel with the relay control (coil)
which actually suppresses the inductive spark occuring with the switching.
These thermal switches however usually are very slow so it might even happen that when opening and closing
there is more burn then necessary and causing premature wear. A switch with a larger hysterisis could fix this issue (e.g. switching on with 85 degrees and off at 75 instead of 80 and 78)

60mph

254 posts

214 months

Tuesday 3rd February 2009
quotequote all
Steve D

Do they fail in the closed position or open causing the engine to overheat ?
I have 1989 audi with 205000 miles and no failure !

Frank

Steve_D

13,802 posts

287 months

Tuesday 3rd February 2009
quotequote all
60mph said:
Steve D

Do they fail in the closed position or open causing the engine to overheat ?
I have 1989 audi with 205000 miles and no failure !

Frank
All of mine have failed open.
I agree, I have had plenty of other cars where the stat has never been an issue.

Steve

Stig

11,823 posts

313 months

Tuesday 3rd February 2009
quotequote all
Maybe they don't like being oeprated at an angle?

738 driver

1,202 posts

222 months

Tuesday 3rd February 2009
quotequote all
No- idea on the fan switch failure but along the same lines, has anyone run their fan switch nearer the engine?
There must exist a much greater difference in temp's between the top of the motor and the rad in the Ultima installation, than in a standard vehicle.
I have read about builders upgrading their fans due to overheating but would you not benefit from having the fan-switch nearer the source of heat so switching took place much earlier?
Ill bet theres a good few degrees drop along those six foot pipes!!

60mph

254 posts

214 months

Tuesday 3rd February 2009
quotequote all
Perhaps the switches on our ultimas get a lot more use than those on other cars ; hence their " premature " failure .

Frank

fastka

156 posts

217 months

Wednesday 4th February 2009
quotequote all
738 driver said:
some really good stuff there
simple and brilliant,
i think that is an excellent idea, well done Dave

wherzmespana

Original Poster:

52 posts

233 months

Wednesday 4th February 2009
quotequote all
Thanks guys. Think I will stick with the factory supplied one. Incidentally, mine failed closed!

Davrianman

487 posts

293 months

Thursday 5th February 2009
quotequote all
Steve_D said:
Finally fitted a Kenlow adjustable one which works great and I'm able to set it just where I want it.

Steve
Hi Steve,

I don't suppose you know the part number of the Kenlow switch? I would like to order one...

Many Thanks,

Mart

Steve_D

13,802 posts

287 months

Thursday 5th February 2009
quotequote all
Davrianman said:
Steve_D said:
Finally fitted a Kenlow adjustable one which works great and I'm able to set it just where I want it.

Steve
Hi Steve,

I don't suppose you know the part number of the Kenlow switch? I would like to order one...

Many Thanks,

Mart
Just their standard stat.


Found here
http://www.kenlowe.com/fans/consumers/fans05.html#

Reference the comments about fitting the stat nearer the engine.

My adjustable is fitted at the rad. I watch the dash temperature gauge (sensor on the engine) and decide if the fan is cutting in at a good time. If not then I open up the front and make an adjustment. Once set you should not need to touch it again. So it does not really matter where the sensor is.

I doubt there will be much difference between front to back on a cold day compared to a hot day and I'm really only interested on hot days.

Steve

ETA I have fitted the control in the corner of the chassis just forward of the battery. In this position it is possible to just disconnect from the rad switch and plug straight onto the new stat.

Edited by Steve_D on Thursday 5th February 14:49

V8OWNER

602 posts

264 months

Thursday 5th February 2009
quotequote all
Ive used the kenlowe one also,
always been a reliable bit of kit.. just wish it didnt look so industrial..

Steve_D

13,802 posts

287 months

Thursday 5th February 2009
quotequote all
V8OWNER said:
Ive used the kenlowe one also,
always been a reliable bit of kit.. just wish it didnt look so industrial..
You could put it in a nice polished box.
Wish I had on the Dakar 4x4. They don't work so well when full of mud.

Steve

ETA Should have said. The replacement I got for the Dakar came from Car Builder Solutions and was cheaper. They also do a housing that you fit inline in the hose rather than trapping the sensor under the hose where it fits to the rad.

Edited by Steve_D on Thursday 5th February 15:00

V8 DOM

3,547 posts

231 months

Thursday 5th February 2009
quotequote all
Steve_D said:
Davrianman said:
Steve_D said:
Finally fitted a Kenlow adjustable one which works great and I'm able to set it just where I want it.

Steve
Hi Steve,

I don't suppose you know the part number of the Kenlow switch? I would like to order one...

Many Thanks,

Mart
Just their standard stat.


Found here
http://www.kenlowe.com/fans/consumers/fans05.html#

Reference the comments about fitting the stat nearer the engine.

My adjustable is fitted at the rad. I watch the dash temperature gauge (sensor on the engine) and decide if the fan is cutting in at a good time. If not then I open up the front and make an adjustment. Once set you should not need to touch it again. So it does not really matter where the sensor is.

I doubt there will be much difference between front to back on a cold day compared to a hot day and I'm really only interested on hot days.

Steve

ETA I have fitted the control in the corner of the chassis just forward of the battery. In this position it is possible to just disconnect from the rad switch and plug straight onto the new stat.


oooooooo. used to have one of these and never could get the hose to seal with that silly pickup.... ended up using a ford escort temp sender that fitted my radtec radiator perfectly..

neat and simple.. also i had an over ride switch inside if i was about to get stuck in french summer traffic...

dom

Edited by Steve_D on Thursday 5th February 14:49

San Diego GTR

469 posts

236 months

Saturday 4th April 2009
quotequote all
Well mine failed today as well. I wound up replacing it with a Painless adjustable unit like Steve mentioned. I've never heard of these switches failing like this?
Paul

60mph

254 posts

214 months

Saturday 4th April 2009
quotequote all
I think I will wire in an emergency switch so when mine fails in the open position I will be able to turn on the fans to get me out of the traffic and another switch to break the circuit when it fails in the closed position ! Did you get your castor sorted San Diego ?

Frank

San Diego GTR

469 posts

236 months

Sunday 5th April 2009
quotequote all
60mph said:
Did you get your castor sorted San Diego ?
I'm working with Ted on it. He's been great helping me sort out a few ideas. The ball is in my court to get some measurements to him.
Paul

XTR2Turbo

1,538 posts

260 months

Monday 27th July 2009
quotequote all
Does anyone know where the fan temp switch is located? Had a quick look and couldn't see it in the rad anywhere.

David

Steve_D

13,802 posts

287 months

Monday 27th July 2009
quotequote all
Bottom of the rad on the left side. You could not see it because the rad leans forward making it difficult to see.

Steve