I have read in a number posts that when you turn on a NS Oscar you need to open the steam valve. THe manual (such as it is) says that on first startup the steam valve should be closed.It is a pain starting with the valve open because if you arent there steam blows out which isnt good. What is wrong with starting with the valve closed ? Anyone starting with steam off without a problem ?
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Hi,
It varies with my Oscar. I never start with it open and usually I don't need to bleed it prior to using it in anger. Naturally before I steam i run it for 15 - 30 sec which removes the water.
I do however on occasions need to open the valve but then I shut it straight away. The reason I need to do this is that sometimes about 30 seconds after turning it on the boiler sounds like it is boiling dry - a sharp crackling sound like there is an cm of water in a kettle. I simply release the air and you can audibly hear the boiler change in sound. It rarely happens and I have no idea if it is causing damage. Maybe get to know your machine and if you don't have an issue while you are around then move to a timer.
Cheers Yabba
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I had almost the exact reverse behaviour as Yabba.. Mine would always start with the wrong temperature if I didn't do the vacuum breaker thing.
The issue is that the temperature is controlled by boiler pressure. So if you don't do the venting thing, you end up with what is called "false pressure" (which is a crazy name, but there you go). The noise Yabba hears is I think the water flash boiling due to the lower pressure in the boiler (when it cools, a partial vacuum forms - so the boiling point is artificially lowered).
So if you want reliable temperature, you need to either manually vent, or put an anti-vac valve in. I did the latter - it is a very simple job. I took off the steam arm feed, put in a Tee with the boiler on one end of the tee, the anti-vac valve on the top and "eased" the existing copper steam tube into the side of the tee. For the cost of the valve and tee, I just don't know why NS don't do this ex-factory...
/Kevin
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Hi Kevin,Originally posted by KJM View PostI had almost the exact reverse behaviour as Yabba.. Mine would always start with the wrong temperature if I didn't do the vacuum breaker thing.
The issue is that the temperature is controlled by boiler pressure. So if you don't do the venting thing, you end up with what is called "false pressure" (which is a crazy name, but there you go). The noise Yabba hears is I think the water flash boiling due to the lower pressure in the boiler (when it cools, a partial vacuum forms - so the boiling point is artificially lowered).
So if you want reliable temperature, you need to either manually vent, or put an anti-vac valve in. I did the latter - it is a very simple job. I took off the steam arm feed, put in a Tee with the boiler on one end of the tee, the anti-vac valve on the top and "eased" the existing copper steam tube into the side of the tee. For the cost of the valve and tee, I just don't know why NS don't do this ex-factory...
/Kevin
I learnt something thanks- Good information. I assume that would account for why when I initially bleed the steam (after initial heating - Light off) and run water thorough the head it immediately turns back for further heating (approximately 5 MINS).
Cheers Yabba
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If you do this when you first power up, yes, the pressure will equalise pretty quickly. If you wait till the heater cycles off, it'll probably be the 5 mins Yabba says before the temperature will be OK (but the opening of the valve will be equally quick).Originally posted by ceeldee View PostThanks a lot guys, very good info. Just to be clear , I only need to open the valve and then close it , I don't need to wait for steam ?
I do commend to you the vac breaker mod! There was a thread here someplace with lovely pictures that inspired me to do mine. It really is an easy thing to do and makes the machine a walk up and turn on exercise without having to think about it!
/KevinLast edited by KJM; 9 April 2013, 08:46 PM. Reason: Further clarification - darn must read it before sending!
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