Heater not starting - voltage required?

[stim]

I have just spent the night in the van and had problems running the heater. It was working fine while we were having dinner but then at some point in the night it stopped working and would not start again. I think it shut off after seemingly spinning up the fan, but not sure about that because I was half asleep. The van is a 2 year old T6.1 Beach with 75Ah battery.

Here is a summary:

• Tried to turn on heating with both control panel and remote using both heat continuously and heat immediately. Always the same result. Heater light would come on and then turn off after a minute or so. Sometimes you would hear it try to start, sometimes not.
• Battery was at around 12.5/12.6v (so nearly full) when we arrived and about 12/12.1v when the problem started. When it did try to start and amps were drawn, the voltage dropped to 11.something.
• The heater would start fine with the engine running and continue to run once the engine turned off.
• My friends with an Ocean next to us had no problems with the heater all night and were also reading the same voltage on the control panel (12v).

I understand that the heater needs a bunch of juice to start but I would have thought 12v was enough? I think I saw a post by @WelshGas somewhere saying the heater will not work at 11.5v or less. Is this rest voltage or the value it drops to while starting? Why would my friend's Ocean with similar voltage be fine? Do you get less voltage drop when drawing current with two batteries? Could it be something else that is causing voltage drop between the heater and the battery? I am wondering whether to push my garage to check this (still under warranty) or whether it is really just the battery (probably not covered by warranty).

Bit disappointed that after only 2 years my battery cannot handle one night of camping with the heater but I guess that is what happens with AGMs (I am not able to plug it into the mains for 24+ hours to keep it in good shape).

Thanks in advance!

 

[flymartin]

I’ve had a couple of occasions recently where the heater in my 2022 Beach would not start, and I had to turn the ignition on and off to reset something, then it worked fine. I blamed the recently OUG9 software update for the glitch and hope it will be fixed in the next update.. My battery was full both times.

 

[stim]

I’ve had a couple of occasions recently where the heater in my 2022 Beach would not start, and I had to turn the ignition on and off to reset something, then it worked fine. I blamed the recently OUG9 software update for the glitch and hope it will be fixed in the next update.. My battery was full both times.

Hi, thanks for the info. What were the symptoms of not starting? Same as mine, i.e. light on and then off after a minute or so?

 

[Corradobrit]

Whats the diesel level in the main tank? The parking heater will not work if the level is below 25% full.

 

[flymartin]

Hi, thanks for the info. What were the symptoms of not starting? Same as mine, i.e. light on and then off after a minute or so?

Yep - click Activate with the knob, light comes on, screen says please wait, after about a minute the light goes off. Turning ignition on then off seems to reset things and the heating works as normal.

Whats the diesel level in the main tank? The parking heater will not work if the level is below 25% full.

Mine was about 80% the first time, I actually didn’t check the second time and couldn’t swear it was more than 25%

 

[stim]

Whats the diesel level in the main tank? The parking heater will not work if the level is below 25% full.

I would have been close to 25% but as I mentioned, it did work when I had the engine running so I guess there was enough fuel.

Yep - click Activate with the knob, light comes on, screen says please wait, after about a minute the light goes off. Turning ignition on then off seems to reset things and the heating works as normal.


Mine was about 80% the first time, I actually didn’t check the second time and couldn’t swear it was more than 25%

Interesting. Did you just turn the ignition on or you had to start the engine?

 

[WelshGas]

I have just spent the night in the van and had problems running the heater. It was working fine while we were having dinner but then at some point in the night it stopped working and would not start again. I think it shut off after seemingly spinning up the fan, but not sure about that because I was half asleep. The van is a 2 year old T6.1 Beach with 75Ah battery.

Here is a summary:

• Tried to turn on heating with both control panel and remote using both heat continuously and heat immediately. Always the same result. Heater light would come on and then turn off after a minute or so. Sometimes you would hear it try to start, sometimes not.
• Battery was at around 12.5/12.6v (so nearly full) when we arrived and about 12/12.1v when the problem started. When it did try to start and amps were drawn, the voltage dropped to 11.something.
• The heater would start fine with the engine running and continue to run once the engine turned off.
• My friends with an Ocean next to us had no problems with the heater all night and were also reading the same voltage on the control panel (12v).

I understand that the heater needs a bunch of juice to start but I would have thought 12v was enough? I think I saw a post by @WelshGas somewhere saying the heater will not work at 11.5v or less. Is this rest voltage or the value it drops to while starting? Why would my friend's Ocean with similar voltage be fine? Do you get less voltage drop when drawing current with two batteries? Could it be something else that is causing voltage drop between the heater and the battery? I am wondering whether to push my garage to check this (still under warranty) or whether it is really just the battery (probably not covered by warranty).

Bit disappointed that after only 2 years my battery cannot handle one night of camping with the heater but I guess that is what happens with AGMs (I am not able to plug it into the mains for 24+ hours to keep it in good shape).

Thanks in advance!

If the Leisure Battery voltage drops to 11.5v at anytime then the heater will closedown.
During startup a Glow Plug is heated up, and takes a lot of amps. Running requires a lot less amps.
This explains why the heater would start with the engine running and continue when the engine switches off.
The Ocean has double the Leisure Battery capacity of the Beach. So although the voltage may be the same in both vehicles a 10amp draw to start the heater in a Beach will show double the voltage drop compared to an Ocean .
So if both vehicles show a 12v starting voltage then starting the heater in the Beach drops the voltage to 11.5v but on the Ocean only to 11.75v. So the heater shuts down on the Beach but continues on the Ocean.

 

[flymartin]

Interesting. Did you just turn the ignition on or you had to start the engine?

No just the ignition. But it’s only happened to me twice so far, so I would only say it might be worth trying next time you have an issue. I’ll monitor mine and update here.

 

[sidepod]

I would have been close to 25% but as I mentioned, it did work when I had the engine running so I guess there was enough fuel.

It doesn’t work like that. Whilst the heater shares the diesel tank with the engine, it has a separate take-off point which is vertically higher that that used for the engine.
The idea being, if running the heater you’re not able to completely drain the tank and not drive away. This accounts for the 25% fuel level question.

 

[pluc99]

How high was the heater set? On the T6.1, the range corresponds roughly from 1=12° to 10=26°.
It may be a bit counterintuitive, but the lower you set the heater, the more often it will cycle on and off, thereby draining the battery faster than it would on a higher setting.

 

[WelshGas]

How high was the heater set? On the T6.1, the range corresponds roughly from 1=12° to 10=26°.
It may be a bit counterintuitive, but the lower you set the heater, the more often it will cycle on and off, thereby draining the battery faster than it would on a higher setting.

On my T5.1 the heater functions as follows.
Switch On, high current use to heat glowplug and high fan speed and fuel pump speed. As the temperature rises to the set level pump and fan speed decrease to low level and amps required drop to very low readings , about 0.5amps or less. Once on the low heat output if the temperature drops more than a few degrees then the output increases to raise the cabin temperature and then backs off and so on ad infinitum. However if the temperature continues to rise then the heater will switch Off until the temperature drops from the requested level and then restart again requiring increased amps to heat the glow plug.
The air inlet on the Drivers, RHD, stepwell has the inlet temperature sensor. If the drivers window is open a few cms then the inlet will be drawing in cabin and cold outside air.

 

[Ch1pbutty]

The fuel level is not so relevant in our T5.1;
It still ran with almost a dry tank (tested during a big family BBQ during heavy rain, van became kids cinema on the driveway during the fuel crisis so couldn’t fill up!…)

So would say its more likely voltage issue. If you can’t get it looked at by VW - A decent yacht yard, motor home conversion specialist should be able to assist as these heaters are quite common.

 

[stim]

It doesn’t work like that. Whilst the heater shares the diesel tank with the engine, it has a separate take-off point which is vertically higher that that used for the engine.
The idea being, if running the heater you’re not able to completely drain the tank and not drive away. This accounts for the 25% fuel level question.

I mean that if the heater ran, then there was enough full (level above tank take-off point) so I guess that was not the issue. Shame the POS control system doesn't give you any meaningful errors. How hard would it be for it to tell me "not enough battery capacity to run heater"?

 

[stim]

How high was the heater set? On the T6.1, the range corresponds roughly from 1=12° to 10=26°.
It may be a bit counterintuitive, but the lower you set the heater, the more often it will cycle on and off, thereby draining the battery faster than it would on a higher setting.

2-3. I find anything over 4 is way too hot, even when it is -10 outside. Why will the heater cycle on and off more with a lower setting? If I understand Welshgas correctly, it would be because it quickly finds the air too hot and so shuts off completely only to turn on again later (and using more battery capacity) rather than staying on but keeping a lower blow?

 

[chockswahay]

How high was the heater set? On the T6.1, the range corresponds roughly from 1=12° to 10=26°.
It may be a bit counterintuitive, but the lower you set the heater, the more often it will cycle on and off, thereby draining the battery faster than it would on a higher setting.

I’m wondering if this is what I have been experiencing ?

I am having REAL heater and battery issues! Help (please?)

I have posted on a couple of threads regarding these issues bit no real answers…… HEATER: I think it’s either faulty or rubbish! It will not stay running for more than 10 mins or so then turns off… van gets cold…..then it comes on again. The problem with this is that it spends a LOT of time...

vwcaliforniaclub.com

 

[willwander]

I’m wondering if this is what I have been experiencing ?

I am having REAL heater and battery issues! Help (please?)

I have posted on a couple of threads regarding these issues bit no real answers…… HEATER: I think it’s either faulty or rubbish! It will not stay running for more than 10 mins or so then turns off… van gets cold…..then it comes on again. The problem with this is that it spends a LOT of time...

vwcaliforniaclub.com

I did suggest you test it on a high setting.

 

[chockswahay]

I did suggest you test it on a high setting.

I did! and it may be the problem (or not, and that is a problem)

 

[chockswahay]

@stim did you fix it? This finally worked for me…..

Yup, I reckon my batteries are done for!

Mine is still on the original leisure batteries coming up for 10 years. It has had to have a new engine battery at 100,000 miles but not leisure. The van was well used for driving but not camping for the first 4 years before I bought it but rarely on hook up. Regularly plugged into the mains...

vwcaliforniaclub.com

 

[stim]

@stim did you fix it? This finally worked for me…..

Yup, I reckon my batteries are done for!

Mine is still on the original leisure batteries coming up for 10 years. It has had to have a new engine battery at 100,000 miles but not leisure. The van was well used for driving but not camping for the first 4 years before I bought it but rarely on hook up. Regularly plugged into the mains...

vwcaliforniaclub.com

It has been better recently because I have been turning on max charge every time I go out in the van. It also seems to work better with the roof open, perhaps as previously mentioned, the heater does not fully shut down and start again. However, it seems to lose charge quickly and the hours rating and the capacity scale (which are both useless) just skip around all over the show. I will likely upgrade to a lithium at some point.

 

[WelshGas]

It has been better recently because I have been turning on max charge every time I go out in the van. It also seems to work better with the roof open, perhaps as previously mentioned, the heater does not fully shut down and start again. However, it seems to lose charge quickly and the hours rating and the capacity scale (which are both useless) just skip around all over the show. I will likely upgrade to a lithium at some point.

Batteries can fail, that's why they have a warranty. I had 1 of 2 leisure batteries fail and it had a significant impact but corrected by changing both batteries.