Revotec fan controller

[p7rider]

No the fan only cuts in at slow speed queuing and standing still. I was concerned that as i have a 95'c switch in bottom hose.  And I think the fan comes on to soon (cold).  Most people seem to use about 85. As the radiator should have about 10'c cooling. 

Hence why I wonder if some hot water goes straight out the bottom hose before cooling in the matrix 

[johny]

Theres no way for water to bypass the matrix but obviously when stationary or very slow moving theres little air flow over the tubes so the temperature at rad inlet and outlet will be much closer....

[Mjit]

If I remember correctly for an electric fan you should set it to come on at the 3/4 mark, the general theory is that the engine will be more efficient running at a higher temperature.

With an electric fan you can do that, as every time it spins it spins at full speed so gives full airflow/cooling.  Out of the factory with mechanical fans our cars had to be set up to over-cool the engine most of the time, making them run less efficiently but meaning (if everything's in tip top condition) you don't overheat in the worst case scenario - say cruising at 70MPH on the motorway on a hot summers day...until you hit a stationary tailback.  You then have a load of heat built up in the engine and just the idle speed mechanical fan to pull air through the rad.

[johny]

I thought it was the other way with any type of fan becoming redundant once the cars moving because the blast of air being forced through the complete matrix is far greater than the fan can produce. Then when driving over cooling can only occur with the wrong (or broken) thermostat or an oversized radiator....

Youre right about heat soak being a potential problem and in my opinion is the most arduous situation so making an electric fan very useful.

[p7rider]

I've ordered a switch that'll come in at 100'c . I'll see where that starts the fan on the gauge.  

I tried pointing a laser heat gun at top and bottom of radiator.  But as mentioned when stationery the radiator will not be cooling as well. There was a drop though , perhaps 7'c 

[AndyTV8]

I have always preferred my electric fan to come on a little earlier, rather than later  -  my logic being i don't want to be in the situation where the temp is already too high to be able to be brought down by the fan.

each engine will probably have its own pattern of behaviour

...... Andy

[Iain T]

I have a sensor in the top hose and set the fan to come on at 95C. On driving the temp on a cold day is 80C and if hotter around 85C then rises if in traffic but the fan ensures the temp never hits 100C.

Iain 

[Graham C]

I have electric fan with a capillary sensor and I believe you can buy an adapter to fit inside the house which allows the sensor to fit without causing leaks. I can't find a supplier. Anyone know of a supplier of these adapters?

Graham

[johny]

Theres this offering:

KENLOWE THERMAL TRANSMITER HOSE TO RADIATOR RUBBER SEAL SLEEVE ELECTRIC FAN OC31 | eBay

[68vitesse]

I use one of these in my Vitesse.

https://revotec.com/product-category/electronic-fan-controllers/

Regards

Paul

[Graham C]

Thank you, I was searching the web for an 1 he trying to find the silicone one. Found it sometime ago and held the page open but deleted it. Now could not find it😀

Graham

[Mjit]

Never been a fan of those capillary sensors - even before I had one fail, which puts it into an open circuit and sets the fan running in the garage until the battery's flat.

Just £15 more than the silicone 'sleeve' for some solid state, non-leaking goodness - https://www.ebay.co.uk/itm/282802366937?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=lpFSprNpStq&sssrc=2047675&ssuid=&widget_ver=artemis&media=COPY (30mm ID and either 90° or 95° - for a Spitfire bottom hose at least)

[johny]

I think this is one of the original mechanical capillary units which has a fluid inside that expands on heating to operate a thermostat contact. Quite reliable and if theres a leak it fails safe and wont start the fan. Like this:

[Mjit]

On 19/03/2024 at 11:02, johny said:

I think this is one of the original mechanical capillary units which has a fluid inside that expands on heating to operate a thermostat contact. Quite reliable and if theres a leak it fails safe and wont start the fan. Like this:

My Kenlowe one certainly went open circuit when the capillary bulb failed.  Never worked out how/why it failed as it switched the fan off after parking one day and failed while just sat there parked.  Recharge battery and reconnect and fan kicked straight in (on stone cold engine).  Pulling the probe from the top hose uncovered an inch long split in the bulb.