Man-cave diesel heater 12V supply......

[DickyDoDah]

Drawing cold air in from outside not as bad as I thought.
I run 2 of these heaters flat out in winter. One recirculating the warm air. The other is outside ish and has just the one duct going inside for the outlet air. Not as bad as I was expecting. Not much difference in outlet temp.

You need to draw cold air from outside for the combustion for a couple of reasons. First off cold air has more oxygen so is better for combustion and secondly as the exhaust must be vented outside there is no Net loss of air in the room. If you did draw the combustion air from in the room and exhaust to outside then you would create a small vacuum in the room that would suck air from outside through any gaps in the structure and get draughts.

If you are referring to the heated room air you should only draw that from in the room so that it can be recirculated and the temperature increased. If the air is drawn in from outside it needs more power to raise the temperature so the maximum temperature of the room will never rise above a certain (low) level. If possible the air input for the heater should be taken from the floor level by using a duct of some sort.

As for heat scavenging from the exhaust I extended my exhaust with 22mm copper pipe as it was the cheapest option which was a bit of a surprise. I then attached aluminium plates to it using 22mm copper clips and painted the lot with matt black heatproof paint. Over the 2.5m length I see a temperature drop of over 100 degrees before it exits the building so there must be a reasonable amount of heat given to the room.

I mounted my heater at high level to make this easier and have extended the outlet vents in two directions using plastic drainpipe. I fitted the 2m of heatproof tube that came with the heater before it gets to the plastic and I've only seen a little bit of distortion in the plastic after running the heater at full blast for a few hours for a test. At some point I will add a low level intake to draw the cold air from floor level but that is at the back of a long list of things to do.
My garage is 4.5m X 12m and it can get quite warm in there so I'm reasonably happy with the setup. I'll add a few photo's tomorrow

 

[fizzy]

You need to draw cold air from outside for the combustion for a couple of reasons. First off cold air has more oxygen so is better for combustion and secondly as the exhaust must be vented outside there is no Net loss of air in the room. If you did draw the combustion air from in the room and exhaust to outside then you would create a small vacuum in the room that would suck air from outside through any gaps in the structure and get draughts.

If you are referring to the heated room air you should only draw that from in the room so that it can be recirculated and the temperature increased. If the air is drawn in from outside it needs more power to raise the temperature so the maximum temperature of the room will never rise above a certain (low) level. If possible the air input for the heater should be taken from the floor level by using a duct of some sort.

As for heat scavenging from the exhaust I extended my exhaust with 22mm copper pipe as it was the cheapest option which was a bit of a surprise. I then attached aluminium plates to it using 22mm copper clips and painted the lot with matt black heatproof paint. Over the 2.5m length I see a temperature drop of over 100 degrees before it exits the building so there must be a reasonable amount of heat given to the room.

I mounted my heater at high level to make this easier and have extended the outlet vents in two directions using plastic drainpipe. I fitted the 2m of heatproof tube that came with the heater before it gets to the plastic and I've only seen a little bit of distortion in the plastic after running the heater at full blast for a few hours for a test. At some point I will add a low level intake to draw the cold air from floor level but that is at the back of a long list of things to do.
My garage is 4.5m X 12m and it can get quite warm in there so I'm reasonably happy with the setup. I'll add a few photo's tomorrow

I am aware of all that.
The stand alone heaters come in a housing like a PC case. Not easy to rig up an intake for the main airflow. My other heater definitely recirculates but there isn't a noticeable difference tbh. Logic tells you otherwise but the outlet air is about the same temp on both!

 

[DickyDoDah]

I am aware of all that.
The stand alone heaters come in a housing like a PC case. Not easy to rig up an intake for the main airflow. My other heater definitely recirculates but there isn't a noticeable difference tbh. Logic tells you otherwise but the outlet air is about the same temp on both!

Oh, I thought you were talking about a diesel heater. Another reason for taking the combustion air from outside on them is that it is possible that they backfire or develop a fault and carbon monoxide in the combustion chamber can leak back into the room. The standalone heaters are as you say completely different and from the descriptions are a very much improved version of the old paraffin heaters we had when I was a kid.

 

[slim_boy_fat]

It is non vented. Very clean burn. Like a gas cooker is non vented.
It is FAR cleaner running than a catalytic calor gas tyoe heater which really makes my eyes water.
Only stinks on startup and shutdown. I whack the thermostat right up to stop it cycling. When room gets too warm I just choose minimum.
Has a 7L tank inside - you can take the tank out to refill whilst running. Made in Japan not China. Very popular in many countries.
Has all sorts of safety features - even an earthquake mode!
I use a CO detector as well just in case.
Had it for about 4 years now. Paid for itself in the first month.
Needs a service once a year which I do myself.

Sounds like the Zibro ones I've seen in a local(ish) large shop, they do chuck out some heat!

 

[fizzy]

Oh, I thought you were talking about a diesel heater. Another reason for taking the combustion air from outside on them is that it is possible that they backfire or develop a fault and carbon monoxide in the combustion chamber can leak back into the room. The standalone heaters are as you say completely different and from the descriptions are a very much improved version of the old paraffin heaters we had when I was a kid.

I was!
And I DO take the combustion air from outside!
The standalone heaters I was referring to are the Chinese diesel heaters in an enclosure.
I also have the other type which as you say is a modern take on the old paraffin ones.

 

[fizzy]

Sounds like the Zibro ones I've seen in a local(ish) large shop, they do chuck out some heat!

Yes that type. Brilliant in the right room.

 

[not done it yet]

Is the exhaust venting into the workshop?

Technically, that comment should be immaterial w.r.t. these cheap chinese diesel air heaters. The whole, complete exhaust should be completely, totally outside, and sealed and separated from the heated area. They are ‘parking heaters’, where someone is sleeping in the warmed area. IF there was to be any CO leaking from the exhaust into the sleeping area, the sleeper may never wake up again - ever.

The suitcase versions are for standing outside, blowing warmed air into the tent, or whatever, and should never be used/installed indoors.

Obviously lots of users ignore the instructions and get away with it. But youtube videos only encourage those, that don’t have a clue, to take a risk with their life that they are not even aware of. One might call that sublime stupidity?

At least those that know the risks install a CO alarm (one hopes) even if they ignored the installation instructions anyway.

Mine still not working but the unit still works, same as the one in the link

It could be (if of any decent quality) that the fan is thermostatically controlled? One would think that cooling not really required at only about 10% of its output. Think fans on stick welders or, while not a perfect analogy, the electric fan operation on an ICE vehicle.

 

[voipio]

The suitcase style diesel heaters that I've seen come with burner-side inlet and exhaust tubing, so they could easily be kept indoors, with the burner inlet and outlet routed to the outside. See e.g:

https://www.amazon.co.uk/Jacgood-5000W-8000W-Parking-5KW-8KW-Trailers/dp/B0BLYWFKTV

 

[not done it yet]

The suitcase style diesel heaters that I've seen come with burner-side inlet and exhaust tubing, so they could easily be kept indoors, with the burner inlet and outlet routed to the outside. See e.g:

https://www.amazon.co.uk/Jacgood-5000W-8000W-Parking-5KW-8KW-Trailers/dp/B0BLYWFKTV

I suggest you look at the proper suppliers/manufacturers installation ininstructions/operation of these things.

EBERSPACHER OR WEBASTO

The chinese installation/operating instructions are RUBBISH and should be largely ignored - for safety’s sake.

 

[voipio]

Excerpt from a Webasto diesel heater installation manual:

"Installation Location - The heater can be fitted both inside and outside the vehicle. When installed on the outside, care must be taken that the heater is fitted in a location that is protected against splashwater and spray."

The Eberspacher installation manual for the Airtronic D4 suggests numerous possible locations inside cars, vans, lorries, and excavators. If the recommended precautions are followed, these heaters are safe in these situations.

 

[m_c]

Excerpt from a Webasto diesel heater installation manual:

"Installation Location - The heater can be fitted both inside and outside the vehicle. When installed on the outside, care must be taken that the heater is fitted in a location that is protected against splashwater and spray."

The Eberspacher installation manual for the Airtronic D4 suggests numerous possible locations inside cars, vans, lorries, and excavators. If the recommended precautions are followed, these heaters are safe in these situations.

The heater body itself can be mounted inside or outside the vehicle, but it should be mounted so that the combustion pipework is completely external to the passenger compartment.

 

[JOEPRO]

It's refreshing to see so many experts here again on the subject of these heaters and how they should or should not be piped. Great work.



Intake inside.

Exhaust passes to outside through the cavity masonry wall.

For those who start with "going to die" etc apply some common sense. In my application this is used in my garage by me. Low level of risk. Whereas a sleeping risk in a mobile home etc is a different proposition.

 

[fizzy]

It's refreshing to see so many experts here again on the subject of these heaters and how they should or should not be piped. Great work.

View attachment 421995

Intake inside.

Exhaust passes to outside through the cavity masonry wall.

For those who start with "going to die" etc apply some common sense. In my application this is used in my garage by me. Low level of risk. Whereas a sleeping risk in a mobile home etc is a different proposition.

Indeed!
I run 2 of these heaters constantly in Winter. Using just kero. One of them lasted for about 5000 hours until a mate filled the tank with bleach whilst I was in hospital last year. Funnily enough never worked after that so had to buy a new one!
Nothing wrong with your install.

 

[Blobber]

While were on about these killer machines what are folks doing to extend the exhaust safely? mine turned up the other day but the exhaust is a bit on the short side so any safe suggestions for a bit more length?

 

[m_c]

It's refreshing to see so many experts here again on the subject of these heaters and how they should or should not be piped. Great work.

View attachment 421995

Intake inside.

Exhaust passes to outside through the cavity masonry wall.

For those who start with "going to die" etc apply some common sense. In my application this is used in my garage by me. Low level of risk. Whereas a sleeping risk in a mobile home etc is a different proposition.

Just for clarity, I've actually been Webasto trained, and know the manufacturer's guidance.

If anybody wishes to ignore the manufacturer's guidance, that is entirely up to them.

 

[Morris]

It's refreshing to see so many experts here again on the subject of these heaters and how they should or should not be piped. Great work.

View attachment 421995

Intake inside.

Exhaust passes to outside through the cavity masonry wall.

For those who start with "going to die" etc apply some common sense. In my application this is used in my garage by me. Low level of risk. Whereas a sleeping risk in a mobile home etc is a different proposition.

Must admit I was beginning to wonder where my sleeping area was in my workshop.

 

[Morris]

While were on about these killer machines what are folks doing to extend the exhaust safely? mine turned up the other day but the exhaust is a bit on the short side so any safe suggestions for a bit more length?

I used some stainless tube I found in the scrap box, a sched 40 elbow and tig glue.

 

[nickk]

Time to fire mine up getting a bit chilly in the shed

Soft northerners!

 

[jsf55]

While were on about these killer machines what are folks doing to extend the exhaust safely? mine turned up the other day but the exhaust is a bit on the short side so any safe suggestions for a bit more length?

There on ebay at about 300cm length ?

 

[Blobber]

There on ebay at about 300cm length ?

Just found a 2mtr length on the bay, chopped in half will do one for now and one for a spare