Do you run your Calor bottles down til they're empty?

Aidan_M_M

I know butane is the poor relation compared to superior propane, but I noticed something interesting and important when doing a Gas test on a motorhome today.

I stripped, blasted and cleaned the burner and flue on a typical Dometic fridge, and replaced the gas jet.
Lit it, ran it for 10 mins or so, nice enough looking blue flame.
Fitted the gas analyser probe to the exhaust, ran for a few mins to let the readings settle... And here's the result.


That's an "off the scale" level of carbon monoxide (CO) , enough to make the meter flash and beep, which has never happened before!

Scratched my head , rechecked the fridge and jet part number, which was fine. Went around to the gas locker, unstrapped the bottle and sure enough it was quite light and almost empty.

Clipped on a new ish Butane bottle lying around, same regulator, ran the fridge for another 5 mins and checked the levels again.


Much better, reasonably good in fact, and would be probably better after more running.

This equates to almost 90% efficiency, better than most household appliances, and in good running order I've seen them up to 93%.


So , apologies for all the longwinded posting, but to sum up, butane gets to be dangerously rubbish when the bottle is low!

Aidan_M_M

Aidan_M_M wrote: »

I know butane is the poor relation compared to superior propane

Butane is cheaper, has a higher energy density. People say propane burns hotter but this is not the case it operates at a higher pressure and we burn more of it.

Propane doesn't freeze so maybe that's a win in the Winter.



What normally happens the CO Aidan, out the fridge exhaust or vents?

Freedive Ireland

Sir Liam is right on the calorific value of butane being better but with the corresponding problem of a boiling issues in winter. Possible items with a low cylinder might be what are traditionally called heavy ends of the gas so along with the stenching agent you could have other bits of gas from inside the cylinder, minute but maybe enough to throw out the efficiency of combustion. Sometimes we smell "gas" when coming to the end of a cylinder. Possibly more probable is the flow rate not being right if it was running out of gas and so pulled more air in, increasing the amount of O2 burnt and giving a higher CO reading in return. I think.
Thing is I would think the flame would be going yellowy if that was the case.

Agent_47

Well went to the recycling centre, saw some regular yellow Butane but no camping gaz or small propane patio bottles,

Chappy was also adamant that they do not give out items sent for recycling so will try elsewhere.
Going the propane route as have had the low temp issue with Butane

I run butane all year round and keep the bottles insulated. It's cheaper and lasts much longer. Even when I was running propane on a butane regulator.

If it's not possible keep the bottles from freezing it pays to have one of each.
I ran with both for 8 months and then decided I didn't need propane.