Heater cable gone caput (II)

[ghost123uk]

Following on from an "aside" I wrote in the other "Heater cable gone caput !" thread, I wrote "my heater water valve cable is caput". This means I am stuck with my heater valve open. Ok in Winter, but not so "cool" in Summer So I got thinking about an easier way round fixing it.

I have often thought the heat control in our vans is a bit crude. To replace my cable will require a lot of work (dash out etc) so I think I can kill two birds with one stone here and fit an electrically operated water valve in the heater pipe, like this =



And have it controlled by a simple cab temperature monitoring and control circuit (which I can build) so it can be set to thermostatically control what ever temperature I wish

[silverbullet]

Been there! You would still be working with/against/in spite of the temparature control lag that results from throttling the hot water flow to the matrix.
Personally I would have the dash out and fit a new cable.

[ghost123uk]

Ummm, the old hysteresis issue. How about making it semi analogue with a variable mark space ratio output to control the valve. Nah, maybe that is getting over complicated. Click, click, click, click, all the time

[HarryMann]

You need one of these to control dat ting... A PID controller..

"A proportional-integral-derivative controller (PID controller) is a control loop feedback mechanism (controller) widely used in industrial control systems. A PID controller calculates an error value as the difference between a measured process variable and a desired setpoint. "

Usually comes with a heavily rated (amps) power relay.
They are veery clever devices and not necessarily that expensive these days.

Your sort of job John I think. . Cracking solution if it all comes in on budget

[scimdiesel]

Just For your info You don't need to remove the dash to do the cable. You'll loose some skin and wish your hands where smaller but it can be done. I think it took me a few hours. Make sure you buy a new clip to hold the cable to the heater valve. Coz mile was S£ag^d.