# Accucraft Royal Hudson Blowdown valve



## Ionian (Jan 19, 2011)

Hi everyone,
I recently purchace Accucraft's Royal Hudson and are preparing her for her first firing.
Can anyone tell me where the blowdown valve is located?
Thanks,
-Doug


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## Charles (Jan 2, 2008)

Posted By Ionian on 08 Feb 2013 05:29 PM 
Hi everyone,
I recently purchace Accucraft's Royal Hudson and are preparing her for her first firing.
Can anyone tell me where the blowdown valve is located?
Thanks,
-Doug
Doug
Alcohol fired, none...not sure about the gas fired but probably the same setup


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## Ionian (Jan 19, 2011)

Thanks for the reply Charles. I do have the alcohol burning hudson.
I guess I was a little confused, since the manual refers to it in the shutdown section. 
I guess I am not going crazy after all .... or








Thanks again,
-Doug


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## David Leech (Dec 9, 2008)

Hello Doug, 
Welcome to MLS. 
IF this is your first alcohol fired, or even your first live steam loco, I would urge you to ask, or seek, help from anyone with experience. 
It is not difficult, but instructions are often lacking or misleading when it comes to actually doing it. 
I know of someone who tried to fire up his Aster without a suction fan, and caused much paint damage. 
There are quite a few of us on this site who are here to assist you with any queries, so ask, and you shall receive. 
Let us know how you do. 
All the best, 
David Leech, Delta, Canada


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## Ionian (Jan 19, 2011)

Thanks for the warm welcome David,
I have been into model steam engines for several years now (mamod, wilesco, pm research, etc.), but this is my first large scale loco (it's been a dream of mine to get here







) 
I have made a draft fan from a computer fan, but will run some test before I try to make steam.
If anyone else has examples of their draft fan mods I would love to see them.
I also noticed that the wicks were not installed I wonder how many folks have tried to fire up without them








It has been about a week since I recieved the loco. I would love to fire her up this weekend. But I am in no hurry!!
Thanks again David,
-Doug


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## David Leech (Dec 9, 2008)

Hi Doug,
I don't think that any of the Royal Hudsons arrived with wicks installed.
Out of interest, with the burner out of the loco and hooked up to the tender, I tried lighting it to see what would happen.
I was most disappointed!
I expected to see a large flame, but there was absolutely nothing.
I guess that there is not enough air for combustion to take place down inside the wick tubes.
Glad to read that the first run went well.
I do enjoy my Royal Hudson. 
All the best,
David Leech, Delta, Canada


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## Ionian (Jan 19, 2011)

That sounds like an interesting experiment. 
I have converted all of my static steam engines to Alcohol by making my own burners.
In fact, the main reason I choose the Hudson was that it was a Alcohol burner.
I did notice some interesting quirks when trying to light the Hudson. Like if I failed to light the burners on the first go, I found that pulling a new batch of air into the fire box with my draft fan help a great deal on the next try.... etc.

Wow what a fantastic picture of your Hudson. Your coaches are amazing. Do you have any close up pics of them (or links to) I could look at?


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## johnsteam (Feb 16, 2008)

Well, I am disappointed with my Royal Hudson. Such attention is paid to exterior detail, but not the water level glass. The glass was too long by about 3/16 of an inch and so the top of the glass covered the the steam port back to the top of boiler. So I was getting constant false level readings, resulting in over filling the boiler and running dry. I shortened the glass and discover another problem, with the glass still removed I inserted a piece of tube into the lower glass fitting and tried to blow into it and could not. So I am up against a major job to access the bottom fitting. 
Mine is a gas burner and has a blowdown valve, it comes off the steam side (top) of the boiler. My experience with industrial boilers it should come of the boiler bottom to blow out sediment and to drain. John


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## Semper Vaporo (Jan 2, 2008)

Yes, the term "Blow down valve" is a total misonomer.

In the real world the "Blow down valve" is used to vent sediment from the bottom of the boiler using the water in the boiler to carry the crud out. A real one is on the bottom of the boiler because that is where the sediment collects.

In a toy boiler like these, as far as I can tell because of where it is mounted, its only purpose is to release all steam pressure at the end of a run, and if left open then the negative pressure caused by the boiler cooling will be relieved through it, instead of contaminating the boiler by sucking oily water back through the throttle (a major source of crud in a toy boiler).

Personally, I would name a valve like these a "Manual pressure release valve". I suppose it might prove more useful as a steam outlet for an auxilary appliance, like a whistle (albeit poor valve for that) or a fuel tank heater (which I think some people have done).


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## David Leech (Dec 9, 2008)

John, 
Sorry to hear about your Hudson. 
If the top was blocked with the glass tube, and nothing coming in through the lower one, I'm surprised that you got any water in the gauge. 
Another up here in Canada had a similar problem and slowly took bit's off until he could be sure that there was no 'connection' between the boiler and the lower water gauge tube, and not just a blockage. 
He then sent it back to Accucraft for a replacement locomotive. 
Good luck, 
All the best, 
David Leech, Delta, Canada


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## johnsteam (Feb 16, 2008)

Thanks David: Having a level of water in the glass is a mystery. The last time I ran it in August 2012 and it ran dry with 2/3 water in the glass, I'm hoping the boil dry did not do damage to cause this blockage, like something melted internally. I've had the Hudson since 2010 and because I did not have a wide radius track to run it on until 2012, it only ran 3 times in August of 2012. So it was just a show piece for the first 2 years. It'll be a while till I get it apart to investigate what I have to deal with, send it back to Accucraft after 3 years, attempt to fix it or scrap it. I would try to fix it but I would probably need parts, fittings, screws, etc. 
I must appologize for using someone elses thread for this issue. 
John Dreveski


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## Pete Thornton (Jan 2, 2008)

I'm hoping the boil dry did not do damage 
I have accidentally run my butane-fired EBT Mikado with almost no water and it shows no signs of damage. (How do I know it was dry? Well, when I worked the hand-pump, I got a very loud loud hiss from the boler and a lot more steam pressure than I had before. I'm sure the new water was hitting the uncovered flues.)


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## Ionian (Jan 19, 2011)

I must apologize for using someone else thread for this issue. 
No worries John, I'm am sorry to here about your troubles with the RH. 
Hope you get it fixed soon! 
-Doug


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## johnsteam (Feb 16, 2008)

This is something that I read once. Butane will not make a hot enough flame to do damage, eg: I have a butane torch and it will not get metal hot enough to silver solder. So I hope this is the same as locos running dry, I hope it would take a lot lot more than just a few seconds of no water in the boiler to do damage. John


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## Semper Vaporo (Jan 2, 2008)

It may not get hot enough to melt silver solder, but it could get hot enough to damage the metal it is aimed at. But that would take a long time and I doubt if the fuel tank contains enough butane to play a flame on the boiler flue/firebox to get it that hot.

One should also know that some of the really "toy" boilers (such as those on the stationary boiler/engines from Wilesco, Jensen and others) might be soldered with regular tin/lead solder (plumbing or electrical solder) and that can be damaged even by the Esbit tabets or Jellied alcohol (Sterno) fire, so it would be best not to fire one of them on butane.

One time I was running one of my Mikes and I noted that it was running really "peppy"... responsive to the throttle and lots of power... then it gave a very brief spurt of power and speed and then just stopped! I went to it, thinking my R/C receiver had maybe died and closed the throttle. I worked the controls on the transmitter and could see that the throttle and Reverser servos were working fine. I looked at the sight glass and it looked low, but was not empty. So I worked the tender hand pump a couple of times and on the 2nd one I could hear the sound of water flashing to steam, and watched the sight glass drain to nothing and suddenly frost up with the same hissing sound of water flashing to steam. I shut off the flow of alcohol to the burners, but that leaves the fire burning for a couple of minutes while the residual alcohol burns off. I tried several times to blow the fire out and just managed to get it to go below the firebox and set fire to the servo cables! Lots of panic over that and the fear of what I was doing to the boiler, but I decided it was worse to inject more water in and risk thermal expansion/contraction damage and by then the fire was out. I am satisfied that no damage was done to the boiler as it is "big" and radiates a lot of heat so it didn't have a chance to get "too" hot. (I did have to replace the servo cables!)

If your boiler goes dry, try to douse the fire as quickly as possible and do not immediately pump water into the boiler. Let it cool down, inspect it for obvious damage as best you can and then refill it and run some more! I doubt very much that it will be at all damaged.

If you are burning Propane or coal then the check for damage should probably include a hydrostatic test for leaks. (Hydrostatic testing is to fill the boiler with WATER... NO AIR and pressurize it with more water (NOT AIR) up to, but not over one and a half (1.5) times the normal working pressure... such as, if your boiler runs at 3 atmospheres [3 bar, 45 PSI) then pressurize it to 4.5 bar [67.5 PSI] and check for leaks.)


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## Ionian (Jan 19, 2011)

WOW I bet you were sweating it out while the burner was dying out. 
I looked at the sight glass and it looked low 
What do you think caused the false reading? 
-Doug


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## Semper Vaporo (Jan 2, 2008)

I was in more panic trying to put the burning insulation of the servo wires out rather than worry much about the fire under a dry boiler. I knew it would burn out soon, but I wish I had not blown across the firebox from the side opposite where I had routed the servo wires (I put the Reverser servo is below the smokebox and the receiver is in the tender so the wires run along and under the running boards, but that is just above the firebox sides).

The false sight glass reading was just surface tension holding a few drops of water in the glass after the level in the boiler dropped below the lower connection. Once that surface tension was broken, probably by the sudden change in pressure when I pumped in a slug of cold water on the hot flues and the bottom of the boiler, the water ran out. Somehow the jarring of the engine running was not enough to cause it to drop out of the glass.


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