Maintenance of your stove
It is a good idea to do some maintenance on your stove. In fact, it is a good idea to know how to do maintenance on your stove. Practice at home beforehand is always better than discovering in failing light in the middle of a snow storm that you don't kno
Maintenance of your stove
It is a good idea to do some maintenance on your stove. In fact, it is a good idea to know how to do maintenance on your stove. Practice at home beforehand is always better than discovering in failing light in the middle of a snow storm that you don't know how to fix your stove and you haven't the necessary tools either.
There are all the obvious things to look for, like damage to the fuel tank or to the hoses. You should replace the hose if it looks damaged, or just buy a new stove and be more careful in future. But there are many other small details too:
- Make sure you actually have the necesary tools for repair: the right spanner (usually supplied) and a fine wire for cleaning the jet is the minimum. Toilet paper is useful for cleaning the stove - and remember to wash the soot off your hands afterwards as well.
- Check any screw joints for good clean mating with no leaks. A bit of silicone grease may make them do up more smoothly, but don't overdo it. A drop of threadlock may be a good idea on the threads after they have been done up, but of course this may make field service a little more difficult. Leaking fuel is deadly.
- Check any O-rings: a smear of silicone grease (usually supplied with the stove) works wonders here. You should do this every year on principle. Done on the small O-rings on the needle valve and on the thread of the needle valve can make adjusting the stove much easier, believe me!
- If there is a pump, make sure it is easy to use and that it works. Many pumps have a leather washer as the seal: a drop of ordinary light oil every so often keeps this soft and effective.
- A drop of oil on the pump shaft helps reduce wear too. It can also make for some metallic goo on the pump shaft which needs cleaning off before you start playing with it.
- If the stove has a tank, check for gunge at the bottom and flush it out.You might be surprised what collects there over time.
- If the stove has a fuel line, check the nut anchoring it is done up tight. If this gets loose you can have fuel everywhere. It can loosen if you twist the fuel line around. This has great potential for disaster.
- If all this worries you, pick a stove which doesn't need much maintenance. Cheap gas stoves are usually much simpler than liquid fuel stoves, while metho stoves are extremely simple, albeit slow.
Dirty and bisbehaving needle valves
A crucial component of both canister and liquid fuel stoves is the needle valve, also called the control valve. This serves not one but two functions. Obviously it serves to regulate the flow of fuel to the burner, allowing you to simmer gently or boil vogorously, but it also serves as a full shut-off valve. While most stoves use one valve for both functions, the wo functions are different. The Coleman Peak Apex II stove is a rare example of a stove which has a separate valve for each function.
Why is it important to recognise the difference between the two functions? Because you rely on the shut-off function to stop the flow of fuel completely, and this has to work perfectly or you will have fuel everywhere. Deadly stuff. But it doesn't matter if the control valve is a bit sloppy: all it has to do is limit the flow to some variable degree. This difference matters when you do maintenance on the valve. Damage the surface of the needle or the valve seat while cleaning and you may still get flow control, but the valve may not shut off completely any more. Get grit into the valve seat (dirty fuel, poor handling of the stove) and you can create a permanent leak.
With all that as a warning, let's look at when and why you might need to disassemble the valve for cleaning. The picture here shows the needle valve out of a Snow Peak GST100 canister stove. The parts are as follows.
- The locking ring over the valve stem which normally stops you screwing the valve right out
- The screw thread which controls the position of the needle valve.
- Double O-rings which seal the connection and keep the fuel from leaking out at the valve stem.
- The slightly tapered tip which is the 'needle valve' part of the valve and does the flow control.
- The steeper shoulder which serves as the complete shut-off part of the valve.
- White gunge on the needle valve, explained below.
The steeper shoulder labeled E is the bit which does the full shut-off. This must be kept smooth to work. The tapered needle bit at D is what varies the flow: if it is rough or scratched little harm is done - but don't damage it anyhow!
This valve was used under some very irregular conditions which arose out some experimental work. Several nearly empty gas canisters had been decanted into a single canister, and in fact too much fuel was put into that single canister so that it was nearly full. This is something you should not do of course. When this canister was used some liquid fuel was splashed up into the stove in the early stages, and this caused quite irregular burning. What had not been anticipated was that the little bits of fuel in the nearly empty canisters apparently contained a very high level of whatever trace odorant gas had been used - left over when the propane and butane had boiled off. When the fuel from these canisters was decanted into a single canister the result was a very high level of that 'trace' odorant liquid. When the liquid fuel bubbled up into the stove and expanded through the needle vale, the odorant gas collected at the needle valve. It may have interacted with the silicone lubricant on the O-rings as well - I am not sure. Anyhow, I ended up with a needle valve (and valve seat) with a certain amount of 'gunge' on it, and this made the valve a bit unreliable. Sometimes I had to open it a fair distance to get it to work - and then shut it back down quickly as it suddenly opened up too much. Cleaning was definitely in order.
You can remove the needle valve itself on nearly every stove I have ever seen for cleaning. You should do once a year and make sure it is clean. Look into the valve seat with a strong light as well, and make sure that is clean. We recommend an ordinary tissue and a soft wooden match stick or toothpick for the cleaning. Once you have cleaned the needle valve and the cavity it goes into you should turn your attention to the O-rings. These should look smooth and not deformed. If they look damaged replace them: they can be bought from many gear shops as repair kits. Usually some silicone lubricant is included. Put a little smear of this on the O-rings and also a drop on the threads to lubricate them. Then reassemble gently. Then test the stove straight away, both for leaks at the valve spindle and for smooth operation. Never take an untested stove walking!
Dirty fuel jets
The other crucial component of both canister and liquid fuel stoves is the fine jet, just after the valve. If this gets even partly blocked you can have a lot of trouble. In the case of canister stoves you will rarely have any problems at all, but liquid fuel stoves can give some problems. In any case, cleaning the jets requires considerable care. You must never ever force anything into the jet which might change its shape or increase its size! If you carry a cleaning wire, make sure it is a loose fit inside the jet and has no burrs at the end!
Many canister stoves have a little bit of gauze mesh inside the jet - presumably to protect the jet from dirt. I have never had to clean a canister jet and I have never seen any dirt on the mesh.
Liquid fuels - petrol and kero, are a different matter. Have a look at any petrol or diesel engine, and you will see a 'final filter' just before the engine. The MSR International Shaker-jet stove comes with a built-in jet clearing wire, as does the venerable Optimas 8R. These fuels seem to have dirt in them sometimes.