A while ago had issues with the pond pump used to provide coolant water for the product condensers. The pump failed and then had hot alcohol vapour coming out the product condenser with the stream of product.
This was on my LM/VM still while in VM mode. The still just sounded different. Suddenly had gurgles in the column. Left hand on the condenser told me there was a problem. It was damn hot. Ran my hand through the product steam at the same time and got steam heat. Hit the kill switch for the element and started looking things over. The pump was on a separate circuit so it should have been pumping. When I lifted the return hose out of the reservoir there was no flow. I did get the pump going but I am no longer confident in it.
I have used two different reservoirs depending on where still was set up. One is not big enough to do a complete run and needed to be pumped off and fresh cold water added during a run. The other one was just big enough for one long run. Decided to rethink the reservoir and pump idea.
Ended up removing the pond pump and attached coolant line directly to city water for the next run. Running the pot still I used a small brass ball valve attached to the hose bib to adjust water flow to the condenser. Water flow was adjusted to keep product output cold. The water coming off the condenser was a very small stream and to hot to keep my hand in it. The Liebig condenser held an obvious temperature gradient for the entire length. The hot water discharge from the condenser was drained into the old reservoir so I could monitor water usage. It used a lot less water to do a run. A LOT less.
Never had a pump fail during a run but have had difficulty getting them to prime and flush the lines. The pump was replaced last July. I think I’m done with pumps.
Removing the pump removed another potential safety variable while running the still.
"What harms us is to persist in self deceit and ignorance"
Marcus Aurelius
I’m not an alcoholic! I’m a drunk. Alcoholics go to meetings!
You said you were able to get the pump going again. What did you do just unplug and plug it back in again? Pond pumps are designed to run 24/7 for years until they crap out for whatever reason. I'm curious as to what caused to stop. Often it can be something in the impeller. I've had pond pumps that were finicky to start, but once they started they would run forever.
I've used pond pumps only a handfull of times and quickly discovered that it was best to first prime the lines with water first then the pump recirculates water easily. It was harder to prime the lines using a pond pump. Depends on the pump too.
The best pumps I've ever used is a 12V diaphragm pump. Many are designed to run 24/7 while others are for intermittent use. They are high pressure so it will prime your hoses easily. They're not cheap like pond pumps, but the one I have has worked for over 15 years on my Reverse Osmosis water filter.
It acted like it was debris in the impeller blade but I never found anything. I unplugged the pump gave it a shake and bump on the bottom of the reservoir.
The whole still is pretty tall. It’s a lot of lift for a small pond pump. Not sure if there was air trapped in the reflux condenser resulting in a steam/ air lock.
"What harms us is to persist in self deceit and ignorance"
Marcus Aurelius
I’m not an alcoholic! I’m a drunk. Alcoholics go to meetings!
Dancing4dan wrote: ↑Tue Feb 22, 2022 5:49 am
Not sure if there was air trapped in the reflux condenser resulting in a steam/ air lock.
Good point. I never considered that as being the culprit. Living in the country on well water has spoiled me when it comes to water consumption. A high pressure pump with an adequate size reservoir should solve all of your pump problems. Those diaphragm pumps/booster pumps simulate home water pressure only it is 100% consistent unlike home water pressure.
I don't know anything about this pump, but it looks interesting. It has an auto shut off feature, but I imagine that can be omitted by just not connecting a tube to it.
I think this is the one I have, but I'd have to go into my crawl space to confirm the model number.
that's my condenser cooling setup. small submerged pump circulating thru two hydraulic unit coolers with fans. I keep the water hose on and handy just in case of pump failure.
Dancing4dan wrote: ↑Tue Feb 22, 2022 5:49 am
It acted like it was debris in the impeller blade but I never found anything. I unplugged the pump gave it a shake and bump on the bottom of the reservoir.
The whole still is pretty tall. It’s a lot of lift for a small pond pump. Not sure if there was air trapped in the reflux condenser resulting in a steam/ air lock.
What is the head height rating for your “small pond pump”? I ran into a similar issue early on using a cheaper pump from Harbor Freight. It was one size under their largest pump and I think head height was rated at 11’. I was using clear line and could see it stopping right at the 6.5’ mark. I exchanged it for their largest pump 20’+ head height and never had another issue.
Dancing4dan wrote: ↑Tue Feb 22, 2022 5:49 am
It acted like it was debris in the impeller blade but I never found anything. I unplugged the pump gave it a shake and bump on the bottom of the reservoir.
The whole still is pretty tall. It’s a lot of lift for a small pond pump. Not sure if there was air trapped in the reflux condenser resulting in a steam/ air lock.
What is the head height rating for your “small pond pump”? I ran into a similar issue early on using a cheaper pump from Harbor Freight. It was one size under their largest pump and I think head height was rated at 11’. I was using clear line and could see it stopping right at the 6.5’ mark. I exchanged it for their largest pump 20’+ head height and never had another issue.
That pump probably would have worked just fine. You just have to prime the lines with water first then the pump doesn't have to work so hard just to recirculate water.
Dancing4dan wrote: ↑Tue Feb 22, 2022 5:49 am
It acted like it was debris in the impeller blade but I never found anything. I unplugged the pump gave it a shake and bump on the bottom of the reservoir.
The whole still is pretty tall. It’s a lot of lift for a small pond pump. Not sure if there was air trapped in the reflux condenser resulting in a steam/ air lock.
What is the head height rating for your “small pond pump”? I ran into a similar issue early on using a cheaper pump from Harbor Freight. It was one size under their largest pump and I think head height was rated at 11’. I was using clear line and could see it stopping right at the 6.5’ mark. I exchanged it for their largest pump 20’+ head height and never had another issue.
That pump probably would have worked just fine. You just have to prime the lines with water first then the pump doesn't have to work so hard just to recirculate water.
I could unhook the line and drop it to shoulder level and water would flow out the end. When I raised it up I could see the top of the water level and it stayed stagnate no matter how far I raised it. It would only flow out the end once below it’s head height. The lifting capability of a pump matters.
Pond pumps don’t run a closed loop, they are draining back into a reservoir. That means all the water they subjected to head pressure the whole time. They aren’t circulating water, in our application, they are pumping water that is recirculating back into an open reservoir.
There is a huge difference between primed hoses and pure head pressure without primed hoses. If the hoses are primed and both ends are submerged, it is MUCH easier for a pump to recirculate water. Just saying.
There is another recent post on HD about a failed pump.
Pumps work until they don’t.
Be prepared for when they fail. Know before hand what events will happen when a pump fails. Where is the vapour going to go? What ignition source is the vapour exposed to? If there is a vapour flash fire what else is going to light up? How much product is within the fire zone? Are you going to be on fire?
This experience led to find a way to simplify my still operation / setup. For me less moving parts is better. Less things to go wrong. I can use city water to eliminate one potential fail point.
Be safe.
"What harms us is to persist in self deceit and ignorance"
Marcus Aurelius
I’m not an alcoholic! I’m a drunk. Alcoholics go to meetings!
Dancing4dan wrote: ↑Thu Feb 24, 2022 5:54 am
I appreciate all of the posts here.
There is another recent post on HD about a failed pump.
Pumps work until they don’t.
Be prepared for when they fail. Know before hand what events will happen when a pump fails. Where is the vapour going to go? What ignition source is the vapour exposed to? If there is a vapour flash fire what else is going to light up? How much product is within the fire zone? Are you going to be on fire?
This experience led to find a way to simplify my still operation / setup. For me less moving parts is better. Less things to go wrong. I can use city water to eliminate one potential fail point.
Be safe.
Plumbing into the city water supply was how I finally went as well. I highly recommend a water pressure regulator set below your supply pressure to help keep flow/pressure constant. Especially if running CM. Without one I could see a slight output change if there was a toilet flush, or water turned on elsewhere in the house.
