LPG heater- fumes

[Neil WyattModerator @neilwyatt]

I've condemned one of these heaters after it set a CO alarm off.

In theory the room was large enough for 2 out of 3 sections to be lit, but I didn't trust it and it took less than a half hour to set off the alarm.

A headache is a sure sign of things being wrong.

Plus it's a great sources of condensation.

Be safe, we need all our readers and forum members

Neil

[Neil WyattModerator @neilwyatt]

Posted by peak4 on 28/11/2019 16:15:58:

Posted by Rockingdodge on 28/11/2019 13:07:49:………………………………..

Maybe not the Professional drivers but certainly many motorhomers, caravanners and boaters do use them without any issues. Granted the quality/longevity can be questionable but there are british importers that give aftermarket support and there are plenty of forums out there doing the same………………………..

I've actually got a Propex propane heater in my Landrover, from when I was sitting for prolonged periods on cold rally stages.

Yes, they are propane, but have a flue and a heat exchanger, such that the exhaust products and the hot air don't mix. I that regard, they are similar to a balanced flue gas wall heater, but with a 12v fan assist.
When Propane was cheaper, I'd considered running a 12v Propex one to heat my small, well insulated, workshop. Water vapour wouldn't have been a problem, as it would have gone out of the flue, along with any combustion by-products.
My new workshops are unfortunately too big to easily heat, at 6.6m² with a double pitched roof, which is why I'm sitting indoors typing, rather than playing on the lathe.

The red 12v Propex ones certainly used to be fitted to some BT (jointers) vans, later being replaced by a different make; They may well use diesel ones now.

N.B. BT/GPO also used to issue propane radiant heaters for use in external jointers' tents. They must not be used in a closed space.
I was reading last week about someone reminiscing on an ex-BT Facebook group. Either he or one of his mates had passed a van they recognised at the side of the road, and stopped to say hello to their colleague. This proved fortunate, as when he opened the back door, they were both out cold with carbon monoxide poisoning, and didn't have long to live; yes they'd used the radiant heater in the van for some reason.

One option for a workshop, other than a Propex or similar, might be a diesel Eberspacher running off a 12v or 24v supply. Just make sure you plumb in the flue correctly and follow the same regulations as a gas balanced flue heater or boiler , with respect to siting in the vicinity of opening windows.

Bill

The balanced flue heaters are a much better idea as all fumes are sent outside. We had one in a camper but despite it never setting off the alarm my wife didn't trust it. I would always use a CO alarm with any gas heater.

Neil

[Clive Brown 1Participant @clivebrown1]

A diesel heater such as an Eber, or a Chinese copy, will output, very roughly, 10kWHrs. of useful heat per litre of fuel, ie 13p/kWhr. at current filling station prices. Mains 'leccy is about the same, so you need to source fuel at bulk heating prices to see a good economic benefit over a simple fan-heater.

Clive

[Roger ClarkParticipant @rogerclark]

Posted by Clive Brown 1 on 28/11/2019 21:55:36:

A diesel heater such as an Eber, or a Chinese copy, will output, very roughly, 10kWHrs. of useful heat per litre of fuel, ie 13p/kWhr. at current filling station prices. Mains 'leccy is about the same, so you need to source fuel at bulk heating prices to see a good economic benefit over a simple fan-heater.

Clive

 

True if you're using diesel but I buy Kerosene at the pump which is considerably cheaper and if you use heating oil for central heating that is compatible as well.

Roger

Edited By Rockingdodge on 28/11/2019 22:21:58

[Ex contributorParticipant @mgnbuk]

I inherited a Clarke "Little Devil" propane space heater when my father passed away. He used it to heat his garage / workshop. I used it once – toasty warm in my garage, but I was horrified to find my motorcycles soaked in condensation when I finished for the evening.

My garage is a stand alone, single skin Marshalite block built double garage around 5.5 meters square internally, with a pitched concrete tile roof. Shortly after moving here I insulated the walls with 20mm expanded polystyrene + 12mm chipboard sheets & floored the loft space. A 2kw electric convection heater makes little or no difference to heating the space & only heats me if I stand over it. My last motorhome had a Webasto Evo 55 5Kw diesel space heater – lots of heat, but a poor ducting installation by the MH made for an unevenly heated van. But it sowed the seed for a more suitable, affordable to run space heater for the garage – but not really affordable to buy, at around £1200 for a Webasto EVO 55 kit.

Then came the Chinese equivalents – £120 delivered for a 5Kw kit. Plenty of reviews for these & very little negative comment, so I splashed out. The UK supplied kit came in a couple of days & contained everything the listing said it would. Lashed up on the Workmate in an hour or so, powered by a 12v 20A switch mode power supply ( the heater draws upwards of 10A while starting up when the glowpin is heated, but drops to an amp or so for the fan when running), it started up first time & really belts out a lot of heat. I have a little anenometer with a temperature display that showed 15 meters/second 70 degrees C airflow at 75mm diameter at the hot air outlet . There is little smell (just a hint of dieselly fumes on start-up, then nothing – and that goes outside). A stand has been constructed out of angle iron and, if the weather can conspire to be decent at a free weekend to get a couple of bikes outside, it just needs the wall drilling for the exhaust pipe to get it in position & working.. Ducting run under a workbench will direct the warm air into the "machine shop" area.

I am currently running on Gas oil, as there is a filling station locally that has a forecourt pump – around 82p / litre when I filled a 25 litre container. At a consumption of around 1/2 a litre an hour, it isn't going to break the bank to run – just over 8p per KW/hr.. The suggestion is that these things run cleaner on paraffin & I have a found a local fuel merchant with a forecourt paraffin pump who charges around the same as Gas oil, so aim to change to that when the first tank runs out.

Main thing to be aware of with these is that the exhaust pipe runs very hot – the stainless exhaust pipe has gone dark brown at the point it leaves the heater & tests with an IR thermometer on the Webasto on my last MH showed over 160 degrees C at the outlet. Something to bear in mind if you have a wooden shed ! The fan noise was a bit obtrusive in the MH but isn't as noticable in the garage.

There is a free-standing cased version with an integral fuel tank available for little more than the vehicle kit I bought – if I were to buy again I would choose this option, as it just requires the 12V DC supply & the exhaust pipe routing outside to be up and running. My DIY frame has taken a lot more building than I thought it would.

Nigel B

[Howard LewisParticipant @howardlewis46836]

The only source of moisture and CO2 in thew workshop should be you! Even you need a supply of fresh oxygen, so ventilation is necessary.

NO heating by direct combustion, because of the moisture and unpleasant gas emissions.

CO is lethal, forming a stable compound with the haemoglobin in the blood which prevents Oxygen being carried.round.

CO2 is not poisonous, as such, but it does not support life, so will suffocate you.

Either use indirect heat, such as hot water central heating, or indirect combustion heaters whereby the products of combustion cannot enter the workspace.

The most indirect is electricity where you can use tubular heaters for to keep frost at bay, and a thermostatically controlled fan or convection heater to keep you warm. The waste heat from the machine motors will help to heat the place.

Howard

[Clive IndiaParticipant @cliveindia]

Has anyone gone for split aircon units – keep you warm in winter, cool in summer?

[SamsarandaParticipant @samsaranda]

Using Gas Oil for heating at 8p per Kw hour seems remarkably cheap, I currently heat my workshop with an oil filled radiator set low on a thermostat and it keeps the workshop warm and condensation free, the workshop is well insulated, however the electricity is currently costing me 18p per Kw hour on full rate and 11p per Kw hour on off peak. I do have solar panels generating 4Kw hours max when the sun is shining, have a 4.8 Kw hours battery so can save some surplus solar and top up at night with the cheaper off peak to use during the day, we are however heavy users of electricity in our household running pumps etc 24 hours a day on koi ponds. I wish I could get energy to heat the workshop for the equivalent of 8p per Kw hour.
Dave W

[not done it yetParticipant @notdoneityet]

A natural gas fired heater might be around 4p per unit – if they are made for this purpose.

I get by with lots of insulation, occasional electric heating while I am working (often just the dehumidifier on 0.7kW is sufficient) and a regular dose of the desiccant dehumidifier (overnight) to keep the relative humidity down. Costs about 7p per night for condensation protection or 10p to keep machine surfaces a little more pleasant for working. Workshop is not that big, mind. Lighting adds 35-50W as there are no windows to lose heat.

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Clive India on 29/11/2019 16:49:42:

Has anyone gone for split aircon units – keep you warm in winter, cool in summer?

Yes, had one for heating/cooling in the house for a couple of years. The latest inverter models are very efficient with a typical COP of about 4.5 for heating. So for every 1 kWh of electricity used they will produce 4.5 kWh of heat. They used to be impractical in cold areas but the latest Toshiba units are rated for heating down to -20 C outside. However the COP does drop at low outdoor temperatures and they can be slow to start when it is really cold as they have to go through a pre-heating cycle in the outdoor unit. Here, where the night time temperature never goes below -8 C they are highly recommended.

Russell

[JAParticipant @ja]

Posted by Russell Eberhardt on 30/11/2019 16:48:55:

Posted by Clive India on 29/11/2019 16:49:42:

Has anyone gone for split aircon units – keep you warm in winter, cool in summer?

Yes, had one for heating/cooling in the house for a couple of years. The latest inverter models are very efficient with a typical COP of about 4.5 for heating. So for every 1 kWh of electricity used they will produce 4.5 kWh of heat. They used to be impractical in cold areas but the latest Toshiba units are rated for heating down to -20 C outside. However the COP does drop at low outdoor temperatures and they can be slow to start when it is really cold as they have to go through a pre-heating cycle in the outdoor unit. Here, where the night time temperature never goes below -8 C they are highly recommended.

Russell

First Law of Thermodynamics?

JA

[Clive IndiaParticipant @cliveindia]

Posted by JA on 30/11/2019 16:54:13:

First Law of Thermodynamics?

JA

Please will you explain the point you are making.

[Robert Atkinson 2Participant @robertatkinson2]

The clue is in the proper name – heat pump These transfer energy from one unit to the other with a delta in temperature. They are more efficent when heating indors because a proportino of the electrical input is converted to heat nd adds to the wantd heating. I've had them in two homes now. Hitachi in last about 15 years ago and Daikin in the current. The Daikin will work below -20 outdoors.

Highly recommended.

Robert G8RPI.

[JAParticipant @ja]

From what I read 1 unit of energy in, as electricity, produces 4.5 units of energy, as heat. Energy is just energy, whether electrical, thermal or anything else. This contravenes the First Law of Thermodynamics.

The World would kill for such a device.

I have nothing against heat pumps, at all. Given the right conditions I would consider one.

JA

 

 

Edited By JA on 30/11/2019 19:42:25

[Robert Atkinson 2Participant @robertatkinson2]

Posted by JA on 30/11/2019 19:38:43:

From what I read 1 unit of energy in, as electricity, produces 4.5 units of energy, as heat. Energy is just energy, whether electrical, thermal or anything else. This contravenes the First Law of Thermodynamics.

The World would kill for such a device.

I have nothing against heat pumps, at all. Given the right conditions I would consider one.

JA

Edited By JA on 30/11/2019 19:42:25

No,

1 kW electrical energy input PUMPS about 4kW of ambient energy from outside to inside. about half the input electrical energy is also transfered so in heating mode you get 4.5kW of heating. an outside looses 4kW. Cooling mode only gives ((in this example) 3.5 kW of cooling.

No magic, works just like a fridge.

Robert G8RPI

[JAParticipant @ja]

Further to my rant concerning the First Law, I have looked up the Coefficient of Performance (COP) for a heat pump. It is the ratio of the energy moved to the input energy. In other words 4.5 units of energy, thermal, would be moved by one unit of energy, electrical. The total energy input to the pump would be 5.5 units and the useful output would be 4.5 unit.

Carnot can sleep happily in his grave.

JA

Robert beat me to the correction.

Edited By JA on 30/11/2019 20:01:49

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