Heater controls - pre-cat Griff.

[holmbush]

Despite trying several 'experiments' I have never fathomed how the heater control works. Does the switch merely operate an on/off valve via a solenoid or is it a progressive action by servo? i.e the longer you operate the switch, the further the valve opens/closes. Any opion would be helpful.

[Wildfire]

I think the longer you hold it the more the flap opens/closes. But then mine have never worked, so I'm not sure.

[Barreti]

This is what the valve and electronics look like

Front

Back



Or is it the other way around?
Probably, depending on who fitted it

Anyway, the switch on the dash just activates the motor.
As this turns it moves the flat arm which is in turn linked to the valve by the bit of coathanger and it opens the valve. Far simpler than you might imagine.

When the bolt sticking out of the arm hits the micro switch the power to the motor is cut so you can't bend anything by holding the switch too long.

Adjustment of this is by bending the arms on the microswitch so it stops the motor at the right time.

Thats it, nothing complicated.

Edited by Barreti on Wednesday 21st April 15:09

[LordGrover]

If it's typical, like mine, it won't make a blind bit of difference anyway. You may get some whirring and maybe a bit of noise from the wing when you switch on the fan but feckall happens really.
Wear a hat and gloves in the winter and take them off in the summer. Job's a good'n.

[holmbush]

Thanks guys. Being TVR, I knew it wasn't going to be rocket science. My experience is as others - there seems to be little difference whichever way the dingle dangles!

[Barreti]

But if your flat bar isn't connected to the motor spindle correctly it might not be opening the valve fully.
Or it could be spinning the motor but not opening the valve at all.
Or if the microswitches aren't aligned properly they could be stopping the valve too.

Did someone say it was easy

[BliarOut]

Or the guts have fallen out of the valve. If I turn mine one way it goes hot, if I turn it the other way it goes cool! Not sure which one to turn mind...