Why does my FBH not turn the blowers on??

[crazy frog]

HI.
if its any help my 2005 MG ZTT Cdti, without any doubt !. As I've had it from new has a factory fit FBH, pre-heater/parking heater which works in 4 different ways.

1. No driver input ,it just comes on automatically when you start the engine below a certain out side air temperature, assuming the engine isn't already hot.

2. On a manual timer or remote factory fob when you've got out of the shower and anything up to 40 mins from getting into a fully locked and alarmed snow / ice covered car. Then the interior and glass is warmed and thawed wipers door locks unfrozen and engine 50-75 % preheated depending on how cold it is outside and how long you have set it to run ive used it at -17c ) and got into a warm car.

3. Parking heater assuming engine is already hot .Whilst sat in car waiting for what ever in cold weather. No ignition needed just manual control turns heater and pump on/off, and once it senses the engine coolant is loosing temperature the FBH automatically fires up.

4. Hot weather venting (cooling, not AC) from I think 400 yards with my remote fob. With outside ambient air temp. Just like opening all 4 doors before sitting in the Baking Oven on hot days, before getting in the car starting engine and Aircon.

All of the above just requires you to shut down with the heater controls set to how you want it to come back on when the FBH starts up or doesn't in the case of Venting. Obviously using your brains and only setting the fan speed to slow for maximum heat uptake from a gradually warming heater matrix or maximum for Venting

All of the above is explained in my drivers handbook and of course the precautions regarding battery drain from MISUSE and time required driving to replenish the higher rated factory fit battery.

2/3 hours in a shopping center/cinema/gym/ visiting a friend a 10 min zap and warm as toast when you get back in. Its a dream in very cold weather.
Its just the same as a truck drivers night heater except they have massive battery banks and some have auto generators.
Paul. Crazy Frog

Hope this helps to clear things up at least with my car and others like Mine.

I have been Told other cars don't have the full features as above + some after market fan delays and GSM Phone activation features. Both of which I personally think are great ideas .but I don't have any Factual knowledge or experience of these. !!!

[crazy frog]

I haven't adjusted my FBH running time settings for years , I set mine for max 30 mins because I never use the timer I only use my remote on/off when I know I've woke up on time haha and got out of the shower.
So I forget the minute increments you can set it to? is it 5 or 10 I think it is 10 min increments but worth checking its not 5 that may be a reason its turning off after 5 mins ?
Know I now nothing technical about the in depth workings. For all I know there could be a mouse rubbing two sticks together.

But here's a thing some years ago I did a coolant flush, and my FBH was switching off after about 5 mins. Having already blead the system I kept checking it for a couple of weeks, some times getting a little more air.
Anyway I don't know if this is just coincidence but the FBH stopped turning off after 5 mins and went back to its normal 30 mins.
Is it possible there was an air lock in the FBH piping because the bleed screw is right on top of the FBH and there being a hotspot turning the heater off.
I AM NOT TECHNICALLY QUALIFIED to answer this question or even know if it has any merit. But got to be worth asking SOMEONE WHO DOES KNOW ?

[crazy frog]

Whilst we are on this topic I have a question of my own.

I some times only do a 2 mile journey park for half a day and return 2 miles.
Doing this 2 or 3 times a week, then nothing for a week. She gets a good 400 - 700 mile weekend run once a month.
So now winter is approaching when its cold damp miserable dark, lights on, aircon on hot (yes hot) for demisting and warmth because its a dehumidifier as well for better demisting and my FBH is automatically on and I haven't pre-heated, just got in and driven.
when I park up and shut down the FBH carries on for up to 2 mins winding down because I haven't yet got up to temperature . Now my point is I'm obviously not parked up with a fully charged battery. So is there a way of stopping this or is it necessary for the FBH to cool itself if that's what its doing ? I'm just thinking of the battery constantly being used after parking up.
I have a smart charger constantly wired up in my glove box and its a 60 sec job to hook up in the footwell, extension lead coming out bottom door gasket all locked and alarmed, which I use just as a precaution. BUT does anybody know about the FBH winding down when not up to temperature.

Thanks Paul

[trikey]

Have a check behind the ashtray, some cars have a loom fitted that plugs into the atc then piggy backs into the ‘normal’ atc loom

This will then fire the blowers regardless of what temperature they are set on (better to leave them on high for the best results though)

[HarryM1BYT]

Originally Posted by crazy frog

Whilst we are on this topic I have a question of my own.

I some times only do a 2 mile journey park for half a day and return 2 miles.
Doing this 2 or 3 times a week, then nothing for a week. She gets a good 400 - 700 mile weekend run once a month.
So now winter is approaching when its cold damp miserable dark, lights on, aircon on hot (yes hot) for demisting and warmth because its a dehumidifier as well for better demisting and my FBH is automatically on and I haven't pre-heated, just got in and driven.
when I park up and shut down the FBH carries on for up to 2 mins winding down because I haven't yet got up to temperature . Now my point is I'm obviously not parked up with a fully charged battery. So is there a way of stopping this or is it necessary for the FBH to cool itself if that's what its doing ? I'm just thinking of the battery constantly being used after parking up.
I have a smart charger constantly wired up in my glove box and its a 60 sec job to hook up in the footwell, extension lead coming out bottom door gasket all locked and alarmed, which I use just as a precaution. BUT does anybody know about the FBH winding down when not up to temperature.

Thanks Paul

Just to say - my apologies for the misunderstanding about the older version of FBH being able to work as a cabin pre-heater - as a standard fitment.


To answer the above - The FBH has a permanent live supply and is programmed to continue to run for a few minutes, after it is told to shut down, if it has not already shut down for some other reason. The burner chamber will be full of fuel and hot. That fuel needs to be burned off and the heat dissipated into the coolant via the pump - so it runs on.



To prevent it is easy enough, just interrupt the supply at the 20 amp (?) FBH fuse. Stopping it doing this would be a really bad idea and it is only drawing a couple of amps to run the combustion fan and circulation pump for a couple of minutes. Lots of other things continue to run for a while after you have parked up, switched off and locked up.



Only the interior fan and the FBH's ignition sequence draw any appreciable current from the battery. It draws a lot of current at first, to power the FBH's glow pin, to start the ignition of the fuel. Once fully ignited, it burns without the glow pin being powered.


So to answer Pete's question as to why his ATC and blower don't turn on - Could it be that the FBH is one of the later design ones, which doesn't output the signal to turn those things on?

[crazy frog]

[QUOTE=HarryM1BYT;2670847]Just to say - my apologies for the misunderstanding about the older version of FBH being able to work as a cabin pre-heater - as a standard fitment.

To answer the above - The FBH has a permanent live supply and is programmed to continue to run for a few minutes, after it is told to shut down, if it has not already shut down for some other reason. The burner chamber will be full of fuel and hot. That fuel needs to be burned off and the heat dissipated into the coolant via the pump - so it runs on.

To prevent it is easy enough, just interrupt the supply at the 20 amp (?) FBH fuse. Stopping it doing this would be a really bad idea and it is only drawing a couple of amps to run the combustion fan and circulation pump for a couple of minutes. Lots of other things continue to run for a while after you have parked up, switched off and locked up.

Only the interior fan and the FBH's ignition sequence draw any appreciable current from the battery. It draws a lot of current at first, to power the FBH's glow pin, to start the ignition of the fuel. Once fully ignited, it burns without the glow pin being powered.







Thankyou Harry,
for giving me a precise and conclusive technical answer to my question. Needless to say its doing what it should and I wont be messing with the fuse.

P.s I've saved a fiver not buying a Mouse Trap, I was sure there was a little varmint under there rubbing sticks and tinder.

Thanks again Paul. Crazy Frog