How to activate a FBH without a timer / telestart

[JohnFol]

I am one of those people who have a FBH, but do not have a timer or remote starting. This means I have to turn the engine on which heats the coolant in order to activate the FBH to , errm, heat the coolant . .. It has always seemed less that satisfactory. In the search for a better solution I've found a way of activating it with a button, and a way of it shutting down automatically after a pre-set time.

I was going to wait until I had a complete How To to share, but with the mornings getting colder I'm posting how far I have got.


The device I found was a "Universal Timer" from Maplin. It's a self build kit, but with my limited experience of soldering it took <15 minutes to wire up.
It offers a start button to trigger a timed relay allowing me to activate the FBH. It also offers a stop button so I can turn it off again.

This is a picture of it taken from the Maplin web site



This is a picture of it mae up (with a box) and the wires that I have attached



The full specification of the timer can be found here:
http://www.velleman.be/ot/en/product/view/?id=8996



My next stages are

1. Run a 2 core cable from pins 3 & 1 on the FBH to the inside of the car
2. Connect pin 3 to one of the 2 blue leads in the 2nd picture
3. Connect the remaining blue lead and the black lead to a suitable earthing point
4. Connect the red lead to a permanent 12V supply
5. Adjust the timer to give around 10 - 15 minutes of heating
6. Use the pin 1 wire at a later date to fire up the ATC.

I've sent a few kryptic messages over the last week, and hopefully they may make more sense. What I need to tackle is how to make it look good.


Ideally I'd like a single button to replace the 2 separate "door bell" styles, but I lack the experience to do this. JDC has made a suggestion and I am hoping that now I have the circuit diagram I can see if it can be put into practice
(Curcuit diagram P15 here http://www.velleman.be/downloads/0/i...nual_k2579.pdf )

The ideal solution will give the on/off push to make features available using one of the std Rover buttons. For example, if the cruise button gives a combination of make / break that can be integrated with the timer then I can buy the button and facia and end up with a really neat fitting

So, I hope this is usefull and any ideas on wiring up the button appreciated

[ColinW]

John,
I cannot understand why there appears to be this idea that a timer is necessary. I have a simple twin cable from the FBH ( pin 3 & earth), to a push on/off switch inside the car. So I go out, open the car, push the switch & leave it, which can be up to an hour. I can assure you that in 15 mins, the water temp will only just lift the temp gauge off the end. The FBH has it's own shutdown feature, so it is perfectly safe.

However, if you want the control to look nice and use an existing soft touch switch with illumination, then you will have to electronicaly latch it, so it will have a toggle action, ie push once for on, push again for off. I think it is possible to user that timer to do that job, using the relay to do the contact closure. Also for future use with the ATC.

If you like the sound of that I can look at that timer cct to give that feature.


PS- just had a look and it is very easy, with one or two new resistors and capacitors- can send you instructions if you want.

rgds
Colin

[JohnFol]

Hi and many thanks for the pffer. Yes please!


The reason for the timer was 2 fold.

1) If it shuts down automatically I presume it won;t waste fuel (I'm less convinced about this than the option below)
2) if I had an "On" switch, then as soon as the coolant had dropped below 60C, what is there to stop the FBH going back on?

[Ralph503]

I too have been visiting Maplins, on one of those spur of the moment events I bought a remote control thingy for £35 (sorry no pics). Wired it up yesterday (15 mins), works a treat, can switch FBH on/off from house.

[ColinW]

Originally Posted by JohnFol

Hi and many thanks for the pffer. Yes please!


The reason for the timer was 2 fold.

1) so it shuts down automatically
2) if I had an "On" switch, then as soon as the coolant had dropped below 60C, what is there to stop the FBH going back on?

It shuts down automaticaly anyway when it senses the the upper limit for the water temp (65C), whether on not the engine is running. If the temp subsequenty drops, then yes it will start again, by design. However, used as a parking heater, you will drive off long before that happens.

I normaly switch it off before I start the car, and if it is still below 5 deg outside and the water temp is still low ( ie <54C), then the alternator volts do the initiation, so it will continue heating if necessary. It would be possible for the alternator volts to toggle the switch to off, but I think that is overkill.

You will find, that if left on, say an hour or more, then it goes thro several conditions of full load, part load and idle. If left on for more that 72 mins, it will shut down, but come back on once the coolant temp has dropped.
So really it is reasonably safe. Even afer the best part of an hour and say 0 degC outside, the coolant temp is only half way and the heater is still running. So you can see, 15 mins won't do an awful lot.


If you send me a PM with your e-mail address, I will send you a drawing and instruction for the mods.

Rgds

Colin

[JohnFol]

Hi Colin, just 1 last question if I may.

The main reason for the timer is in case I forget to turn the FBH off. I can imagine getting to my destination and having it fire up as soon as the car cools down.

Anyway , PM sent.

Much appreciated