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RioGrandeFan

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Discussion starter · #1 ·
After I am done running my model for the day and after it cools off I notice the throttle is stuck to the point where I need to use pliers to free it up. Once freed up it is fine and only happens when the model has cooled off. When the model is hot and I close the throttle I am not using any excess force. Any reason for this?

Thank you.
 
#2 ·
Yes the reason is that when you fully close the regulator when the engine is 'hot' and then it cools down the metal around contracts onto the regulator spindle and 'tightens it's grip'. I usually crack open my regulator when I have finished a run and of course boiler pressure is nil and that stops this problem, also a good idea to put valve gear in mid position to eliminate engine creep if boiler has some pressure when doing this.
I do this when I remember of course, so if I forget I just go through my lighting up routine and when it gets hot again the regulator spindle free's up again to move easily.
Russell
 
#4 ·
It's worth noting that you don't want too much throttle open as it cools, as the throttle pipe goes through the lubricator. You may suck some steam oil into the boiler, which can be quite messy, I'm told. If you have a Goodall valve or a check/clack valve to feed water in to the boiler, then they will pull in water as the boiler cools and the steam condenses. If you have a blowdown, then open it and let the cooling boiler use it to stabilize. The throttle should then be gently closed but not tightly.

P.S. On one occasion, I fire up my EBT #12 but the r/c throttle had no effect whatsoever. It transpired the throttle was stuck closed and the r/c crank was slipping on the shaft. I obviously had closed the throttle too tightly.
 
#5 ·
Good point Pete, I forgot about the lubricator and I always blow down or leave a blower valve open before I crack open the regulator.
And Rio Grande Fan you aren't being a pest as we all like to pass on knowledge but don't know where to start to people here will chime in with different aspects and I learn all the time from others , both experienced and inexperienced.
Rusell
 
#7 ·
Another thing to think about, when the boiler cools it forms a decreased pressure vessel. Whatever gas of vapor is in there will occupy less volume. This could cause some problems with opening the throttle. I added Goodall valves to all my steamers and this lets the boiler suck air as it cools and have had no problems as you have.
Opening the blower should also allow the pressure to equalize and avoid the problem.
 
#9 ·
RioGrandFan,
I am late to this party, but first of all, "Been there, done that." If you forget to loosen the throttle when cooling down and it sticks, I world reiterate to you to reread Russell's comment on reheating the boiler (with water in it) to un-stick the throttle. It is best to never use pliers to free up the throttle. You might also loosen the whole throttle assembly. ("Been there, done that, also!")
Dan
 
Discussion starter · #10 ·
Better late than never!

Last time I ran the locomotive and I was done I closed the throttle, left the blower open to relive the pressure, once the pressure was at zero I closed the blower and slightly opened the throttle until the loco was completely cool then closed the throttle. This seemed to work for me.

Maybe another topic but I'll ask here. When should I use the blow down valve on the sight glass? I use it every time I want a quick "accurate" water level reading in the boiler but should I be opening this every time I'm done running? Or does it matter?
Thanks!
 
#11 ·
That is your preference. If you will be running in a few days, just save the water in the boiler. 'MY' preference - if I run an engine that will be not used for a considerable (?) time, I will drain the boiler. With a little pressure in the boiler, opening the blow down valve on the sight glass will pretty much empty the boiler. (with a little help from holding the engine on a angle) Lots of people have an opinion about draining the boiler. For copper boilers, I use the above preference. For my Regner and Mamod brass boilers, I make sure that I empty them if they are not going to be used in a day or so. Again, lots of opinions are available. My opinion and $5 bucks will buy you a cup of coffee at Starbucks!
Dan
 
#12 ·
The problem also arrises because most often the regulator is quite up front of the boiler (usually under the dome with Asters) meaning that the fairly long rod which reaches the cone point will also feel the loss of expansion during the cooling process. This in turn forces the cone against the throttle neck, locking the throttle. I have a friend over here in France who does a good deal of business repairing or building up kits for people (A sort of mini TRSservices) You can't imagine the number of locos he has had to dismantle completly to fix this and often to re weld the pointed throttle piece to the rod, it is often separated in the incident!
So not only you should open the regulator once shutting down, but never try to open it without first heating up the boiler (with water in it of course) before trying to open it, most often you won't need pliers to do it then. This is a very common incident on Asters.
This is why assocations like G1MRA and forums like this one are usefull, they permit people with experience to give useful info to tenderfoot steamers.
Happy steaming, Simon
 
#13 ·
If you have one of the new Accucraft " Peckett" models follow the advice listed above. The locomotive has a stainless-steel throttle valve and will lock in the closed position. Mine arrived with the throttle closed and was stuck and had to be heated to release the throttle spindle before operation.
Charles M .
 
#14 ·
What I do with mine, manual or R/C, slow the throttle down till the locomotive is just creeping, then slowly move the direction rod into N position, the throttle is still slightly open the loco can cool and the throttle is still free for the next run. I also crack the water fill so the contraction of the steam can easily draw air.
 
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RioGrandeFan
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