Primus No10 Burner - Flame Issues and Other Question(s)

Hi all

Just got my recent 1st purchase of a Primus 10 stove working and have placed it under my Hestia 10 outdoor oven.

Fits perfectly in the oven alcove and is gradually heating up the oven (see the photo).

However, I am not happy about the flame on the burner. It is burning ok, but the flame is very yellow at the top, but blue below it and is only radiating out from one side, despite my pricking it several times with the pricking tool.

I am using paraffin to burn and is was lit with meths in the cup.

The pump is working ok and when pumped increases the flame height and intensity, for a while. The pressure does drop off after about 5 minutes, but I presume that is normal.

Any pointers regarding getting a better bluer flame would be gratefully received.

Also why the flame is only flaring out on one side?

Finally, the last photo shows an item that came with the stove. Does anyone know what it is used for? Is it to go over the top of the burner trivet to direct the flames more vertically?

Thanks in advance.




Thanks.

 

Good evening, the No.10 would originally have been fitted with a large silent burner, this is the reason it was specified by Condrup as being ideal for oven use. In all other respects it is the same as a No.5. Yours has gained a roarer burner at some point.

Have you tried pricking the nipple to clean it? That may cure the off centre flame.

From your description, the stove is losing pressure. It will give best performance and reliability if you give it a service, as the seals are likely hardened with age and are leaking. The filler cap seal and pump valve seal (commonly referred to as the non-return valve/NRV seal or 'pip' on this site) are the usual cause of leaks, they are consumable service items with a limited lifespan.

The item in the last photo is a heat deflector plate, it sits over the tank top to stop the tank top overheating (potentially melting the soldered joints). It is required when using a stove in situations where there is a lot of thermal feedback- as in heating an oven- so it's great you have one.

 

Hi, Sorry the last comment is slightly wrong. The last photo shows the “disc” that came with the Hestia oven.

if anyone knows what it is used for I would most grateful.

 

Hi Blackdog,

Thanks for replying so quickly.

I have pricked the nipple several times, using the Primus tool, and the “pin” has gone down its complete length into the nipple, and I have tried to “scrap” it around to clear out the nipple hole but the flame is still on one side.

I think I will order some new seals for the burner as the previous owner did say it has not been used for a while.

With regard to the deflector plate, would that sit on the burner cup, just below the burner, or down resting on the tank itself?

Thanks.

 

New seals all round would be a good plan to start with, the stove will hold pressure reliably and may burn better. Is the pricker a close fit in the nipple, or is it very slack (admittedly it's a bit difficult to judge)- a worn jet orifice can lead to poor combustion.

A poor flame may be caused by other issues with the burner, such as the nipple being worn oversize, a leak between nipple and burner, or a crack in the burner itself, heavy carbon buildup inside the burner. Wait and see, hopefully nothing too severe.

The plate with the chain attached rests on the tank and keeps the tank cool, for the safety of it and your fingers when you need to use the pump or air release valve.

 

As Blackdog has said, the device in your last photo sits on the stove tank (slot accommodating the burner riser tube) to protect the stove tank from an excess of radiant heat. An accessory from Primus for use with any large pot (or the Hestia) likely to direct radiant heat down onto the tank.

Your stove’s leaking air. Pressure dropping after five minutes is not normal. Earlier today I boiled a chicken carcass outdoors for a couple of hours to make stock with THIS Chalwyn. After initially bringing the water to a boil I set the tank pressure to produce a steady simmer and along with checking the water wasn’t boiling dry gave the stove pump a couple of strokes, merely, every half-hour or so to compensate for the reducing fuel level and consequent increase of volume of air above the fuel.

 

Primus Heat-Shield


Primus #1/#5 heat shield

 

I’m wrong, on the spirit cup. Thanks @kerophile for the demonstration.

 

@Kevmeister

In my own experience, flame issues of the type you are currently experiencing tend to be due to a jet issue, whereupon replacing the jet has then cured the problem.

Whenever replacing a jet or refitting a burner, it is a good idea to apply copper grease to the threads. This provides additional sealing capability and also makes any future removal of these parts much easier.

Pharael.

 

Thanks guys for your input. I will try out your suggestions.

 

Hi, with regard to Blackdog’s entry on last Sunday at 08:09, does having a silient burner entail a complete new burner top, or just the addition of a brass flame spreader inner and outer cup?

 

My photo of the burner head is shown in my original entry on this thread. Thanks.

 

Hi @Kevmeister, you'd need a complete burner, including the inner and outer burner caps.

 

Okay. Thanks. I just bought a Primus no10 with the silent burner, (not yet arrived), so I hope this is the right one.

 

@Kevmeister

This is the burner fitted to a Primus No.10



My No.10: 6-row outer cap, inner cap fitted with an extending spigot. The jet is hexagonal.



Pharael.

 

@Kevmeister

This why the Primus No.10 was recommended for the Hestia 10…

#2 No.10.



Pharael.

 

Pharael thanks again for your help. I see from your photo the reason why the no10 stove is required,; the flame intensities are completely different!

 

Pharael, can I ask you what products you used to get your stove from its original state, in you first photo, to the pristine look in your latter photo?

 

I have several No.10’s, some with original patina and one which was restored to its original condition (as above).

I use citric acid and Autosol.

I would strongly suggest reading through @kerophile excellent post on stove restoration here

Pharael.

 

Thanks again Pharael.