Ping Pong Ball Check Valve or Roto Damper

[Mache]

I have a BBQ Guru 10 CFM Pit Viper blower with a BBQ Guru Small Universal / Weber Adapter fitted to my 18" WSM. During recent cooks, I have experienced runaway temperatures and have had problems starving the fire of oxygen to bring the temperature quickly back into range. I am considering building either the Roto Damper or the more simpler ping pong ball check valve to address this issue.

I have ordered an additional 1.25" OD o-ring nozzle from BBQ Guru (the same nozzle that is on the Pit Viper) and would like to insert the damper or ball check valve in series between the WSM and the blower.

With the ping pong ball check valve, I will need to set it up so that the ping pong ball can use gravity to close off air flow. Because of this requirement, it may require additional PVC piping complexity.

While the Roto Damper does not depend on gravity to operate, it is more expensive to build and more complex to control.

I have a 4.0 HeaterMeter and was wondering which approach I should implement.

I would love to hear the forum's thoughts.

-- Mache

 

[Tom Kole]

The servo driven valve works very well. I have never used a ping pong ball valve but the graphs that have been posted look very good. Since the ping pong valve can be put together by anyone with very little investment, I would say try it and see what you get. If you are not quite satisfied, send Ralph an email and buy a servo driven damper.

EDIT: If you are getting runaway temps on a WSM, you probably need to get your leaks under control. In my experience using WSMs and an HM, thermal losses were enough to keep them under reasonable control with just a fan and no damper.

 

[Mache]

Thanks Tom, good advice.

My only concern is that the ping pong ball check valve is gravity-based. To have enough ground clearance, I need to first pipe up from the BBQ Guru Universal / Weber Adapter with extra PVC to gain some height to allow the blower to be on the bottom of the ball check assembly. For the WSM, it would it would look pretty kludgy. The Roto Damper, not dependent on gravity, would definitely be a cleaner solution.

My WSM is around 20 years old and while pretty stable at 225F, runaways have happened around 200F or lower. I know the stock door is very leaky. My plan is to replace it with a Cajun Bandit and look into Nomex gaskets between the joints and the door. Once I do that, I should have control that would rival a BGE.

BTW, I grew up in Baltimore. Nice to see someone from my home state.

-- Mache

 

[RalphTrimble]

I echo what Tom said. in my experience WSM type of pits lose enough heat that they can be controlled with just a blower, that is what I use on my thin walled WSM type smoker and it works great (just a blower connected to my "air burner", no valve at all).
I think if you move on the nomex and seal up your door and make sure your other vents are sealed you should be able to control that pit without a damper or valve.
Like Tom said, the ping pong valve is REALLY CHEAP to make, so if you feel you really need a valve perhaps try that one... As for fitting it on your WSM, the last ping pong valve I made was shorter than a Bic Lighter, so you wont have to go up too far to come back down to that size valve. After I broke my first servo flap valve I always keep a ping pong valve on hand in case I have a servo failure or something, though my prototype roto damper is still working great after sitting outside for months so I don't think I will be needing the ping pong valve, but it is nice to have on hand because it is a very simple solution to overshoot. The ping pong valve DOES work great, it will cure your overshoot if the rest of the pit isn't leaking too much... Of coarse if you want a roto damper you can shoot me an email.

 

[Mache]

Thanks Ralph,

The fact that I can make a ping pong valve the size of a Bic Lighter is something I did not remember from the thread. I will re-read it. If it is that compact, I agree, its the way to go. My interest in all this was to do temperatures lower than 225F reliably. Right now, that seems to be the lowest consistent temperatures I can get with my rig. Sealing it up and putting in a ping pong valve will certainly extend its range.

-- Mache