Hi folks, two weeks ago i found a Optimus Nova on amazon for "only" 85€/110$. From the pictures it looked like it had the old CEJN-coupling so i didn't hesitate and bought it. When it arrived i was disappointed because it had the new bayonet-connector. Would have been to good to be true! Nevertheless i'm gonna keep it because now i can use my old one to play with it an convert it to an regulated stove with an stainless generator-tube. 8) That was on my mind for a long time now since i had problems with simmering in cold temperatures using my silent-cap and kerosene. A few months ago, while aimelessly surfing the web, i found a picture of a new Optimus Nova pump on their website. The location of the NRV was different. Surprisingly it is only shown on their Swiss and French site Swiss Optimus site Unfortunately they showed a picture, where the NRV is mounted on the wrong side. Makes no sense in "off"-position When you look at the German, Scandinavian, International and Asian-Pacific part of the site the old pump-design is shown. International Optimus site For Canada and the United States they don't even show a spare-pump United States Optimus site So, to cut a long story short, here are two pictures of the "new" Optimus Nova pump: The NRV is now positioned upways("ON"-position), above the fuellevel, so that in case of a failure no liquid fuel escapes from the stove. Compared to my older Nova(series with bayonet-coupling and leakage problems)there are also other differences which i'm gonna show to you during the next few days. Greetings, Fenris
Fenris, it loooks like the NRV barely will clear the lip of the opening is that the case? Thanks for the pictures.
Hi Big BTU, the NRV won't even fit if put straight onto the bottle. But to put the pump in you just need to insert the tip of the NRV at an slight angle first. It is easier than putting an Coleman Apex II pump with its air/fuel-mixture-tube construct into its bottle Took some pictures: I haven't measured the clearance from the NRV to the inner of the bottle, but if the pump is inside (not yet in the threads) you can easily let it touch the bottle. So I would say it is located about 2mm away from the bottle-wall: (Angle of vision is a bit distorted ) BTW: I think this new "safety feature" will only work properly on a full fuel bottle if the thread of the NRV is sealed. Otherwise liquid fuel can still enter the pump via the thread which is still located underneath the fuel level for some time. Also got now some pictures of other main differences/changes I found with the latest Nova. Regulating-spindle: I will have a look inside the burner with an borescope to see how the new regulating spindle-tip closes the orifice completely since it has not really a cone. Closing it with the small face behind the tip might produce shavings which then could block the jet. We'll see what happens after some weeks of use and abuse 8) Attachment of regulating-spindle: Now they use the same screw which is used for the on/off-valve on the pump. I liked the brass screwcap with its coarser thread more
Hi Fenris, are you considering to exchange the bayonet connector with an Rectus/CEJN Adaptor? And if yes, which material/metall would you choose (since the built the adaptors out of brass,steel, alu)? Regards
Hi Ingwer, Nice to see you here Yes, i'll change the the connector, since i had bad experiences with the bajonet thing on my first Nova. I want to use the CEJN connector. I will try to get one via special-order from Globetrotter. That worked fine 3 years ago. If i can't get it there i'll take an rectus connector. To be honest, i don't care about the material that much. I take what i get. Important form me is the material of the O-rings inside. I can't remember exactly which materials were available, but i know that there were some, which were not useable for fuel! So thats what you should primarily whatch out for when you buy those. Schönen Gruß, Fenris
Hi Fenris, pretty interesting, those are some major design changes. What is your opinion abut the spindle change? Do you think it will regulate the flow of the fuel better? Thanks Fenris.
Hi Big BTU, I'm gonna fire it up tomorrow 8) Then i can tell you something about the influence of the spindle-design change. To me, the adjustability was already ok. Not really a need for a change there. I think one reason for the design change might be that without the cone the spindle won't get stuck after cooling down like it does with the old design. Maybe customers have criticized this? After the first firings i noticed the jamming of the spindle and just stopped shutting the stove off with the regulating spindle. From then on i always flipped the bottle just before i was finished with cooking to let the fuelhose run dry and let the flame go out. Then i simply leave the spindle open. Leaving the spindle open while pressurizing the bottle again only happend one or two times...
My compliments Fenris on a really fine, informative, well-illustrated and well-reasoned post. Looking forward to hearing your thoughts about the performance of the stove. Your concern about the material of the 'O'-rings is justified. When I stripped a CEJN fitting ( link) I found that a Primus Omnifuel spare 'O' ring was a good match and it could obviously be relied upon to be fuel-proof. John
John, thank you for your compliments Since i always learn something new here on CCS it is a sheer pleasure to give something back to all you stovies! Before i continue with the Nova i'd like to explain, why it is so important to make shure you have the right O-rings in your coupplings: Companies like CEJN or Rectus produce their coupplings for various media! Not only for fuels, also for other liquids or pressurized air, gases etc... So please make shure you get a coupling with a suitable O-ring material like Viton(FKM), Nitril(NBR) or Fluoroelastomers (FVMQ). These are only examples. Here you can have a quick look if the material you can get is suitable: compatability chart If you search the web a little you will also find more information about operatingtemperatures and stuff like that. So, now lets get back to topic Before i fired the new Nova for its first time i had a look inside the burner with a borescope. I placed the camera of my mobile phone in front of the eyepiece and took pictures. Sorry for the bad quality: New Nova: Old Nova: Like i presumed the spindle from the new Nova causes right from the beginning small scratches inside whereas the old spindle with its cone just pushed very little material away(after 4 years of excecive use!)You could see a very small collar where the cone begins. I'm really looking forward how the scratches affect the use in the future. Sadly i found small shavings from the machinework inside the burner. But that was also the case with the old one Now to my observations on its performance: Unfortunately i wasn't able to let the two stoves burn side by side because i already cut the old burner into pieces 8) But i think the overall power is the same. The adjustability feels slightly more accurate. With my old Nova there was half a turn of the spindle from simmer to full throttle whereas with the new Nova it is three quarters of a turn. EDIT: I almost forgot to say that the new spindle also gets stuck when turned in and the stove cools down.
