March Pump - AC-3C-MD

[Cuzco_Brew]

Hi All,

Looking for some advice on a pump. First things first, I live in Peru so for practicality reasons I can't just walk down the LHBS and pick up a pump, ordering one from the US is also out. Good news is I have found a march pump for sale down here in Peru, but it's not the standard 809HS model that everyone seems to use for brewing, its the AC-3C-MD. Now the vender has said it's identical to this one AC-3C-MD. Obviously it isn't this exact pump, I have asked for a few more details as to where the vender came accorss it (they aren't that common down here) and if it's new or what condition it's in.

The specs for it can be found on the march web site here http://www.marchpump.com/series-three-info.htm

The question is, is it suitable for home brewing?

 

[schmagy]

says it is used, and came out of a laser chiller.... pump itself would work fine. What is unknown is the coolant used to chill a laser. Probably not to exotic, but still not ideal.

Looks like it comes with a temp controller board. Might work well for a fermentation chilling setup.

 

[Cuzco_Brew]

The vender says it's Identical to that one on ebay, but it isn't that particualr one. So no idea if it's new or used.

 

[Catt22]

It may work OK. I don't see anything in the specs that would be a deal killer. The ebay one is way overpriced. How much is your guy asking for his? You said buying it from the US is out of the question. Why is that? Won't any of the vendors ship one to you or what?l If that's the case, maybe you could hook up with someone on the forum and have them buy one and ship it to you. That would require some trust on your part and there would be some risk involved, but then again, the money involved isn't all that much really. I'd probably ask one of the more well known guys here. Are there customs issues maybe? I'm gonna guess that's the main problem, not the risk.

 

[lanvp]

One important requirement for a home brewing pump is the capacity to transfer hot liquids. There are many low flow pumps available in the market but the choices narrow when you need a food grade pump that can handle liquids up to 250F (121C). That is why many home brewers use the March 809 pumps. You should ask the vendor for the actual spec sheet just to be sure.

Buena suerte!

 

[Cuzco_Brew]

From what I can tell from the specs off the March website, it's only rated to 90C not 121C. That isn't ideal, but as water boils at 88C up here at altitude I figured it might be ok. The vendor says it’s used and it’s about $160US. Might hold out and get for someone to bring me one from the US.

Customs is the issue with buying one from the US and sending it down. They tax you not only on the value of the item, but also on the cost of shipping.

Thanks Guys

 

[Catt22]

The temperature specification of 90C won't be a problem. That equates to 194 F. There's a common misperception about the temp specs on these pumps. The specification limit relates to the strength of the plastic pump head. The plastic (and most other materials) lose strength at higher temperatures. These pumps are designed for circulating hot fluids in closed systems where the line pressures can sometimes approach 200 psi. IOW, the working temperature limits relate to the maximum system pressure. It has nothing to do with the food grade issue. Since we home brewers are typically dealing with only a few psi of pressure or so, there's no chance of the pump housing failing due to exceeding the temperature limit. Additionally, it's near impossible to pump boiling wort or water as the pump will likely cavitate well below 212 F. The best I can do with my pump is about 200F before cavitation occurs. Most of the more common March and Little Giant pumps heads can easily handle the temperatures and pressures we encounter. IIRC, my LG pump is rated to only 200 F. I've been brewing with it for more than five years without a single problem.

 

[lanvp]

The temperature specification of 90C won't be a problem. That equates to 194 F. There's a common misperception about the temp specs on these pumps. The specification limit relates to the strength of the plastic pump head. The plastic (and most other materials) lose strength at higher temperatures. These pumps are designed for circulating hot fluids in closed systems where the line pressures can sometimes approach 200 psi. IOW, the working temperature limits relate to the maximum system pressure. It has nothing to do with the food grade issue. Since we home brewers are typically dealing with only a few psi of pressure or so, there's no chance of the pump housing failing due to exceeding the temperature limit. Additionally, it's near impossible to pump boiling wort or water as the pump will likely cavitate well below 212 F. The best I can do with my pump is about 200F before cavitation occurs. Most of the more common March and Little Giant pumps heads can easily handle the temperatures and pressures we encounter. IIRC, my LG pump is rated to only 200 F. I've been brewing with it for more than five years without a single problem.

I understand your point of view but have to disagree a little bit. The rating of the pump is for operational temperature, I agree with that. But, the pump is the device pressurizing the line. Meaning, when you close your valve with the pump running, the line will see maximum pump output pressure (right?). Unless you have a pressure regulator. My concern is that you do not have all the data on the head material. It may be a strong polymer with a low TG (glass transition temperature). This is the point at which the plastic will start to loose structural strength. I do agree that the chances for an exploding head are near to none but the life of the device may be limited. I look at the pump as a complete system made of many components. The system will be as strong as the weakness link.

The other concern with temperature and food grade is the interaction. Like you know, most polymers will continue to out-gas throughout the life of the part. A good example is the film build up on the inside of your car windows. That oily film that coats the glass. Outgassing or leaching process accelerates with temperature. Since we do not know the origin of many of the pumps in the market, "food grade" is a cheap insurance to avoid some of the nasty stuff. If you do not care, then more power to you. I do like to limit the exposure when I can. And yes, it is just a tiny amount but I do not want a "third eye", an extra limb or an exotic illness (just kidding!). My point is that designers will select the best material for the application intended and that may not be the best selection for "food contact". It may be great for resisting chemical attack from a coolant, not so good for beer drinkers.


When every thing is said and done, it comes down to a matter of choice (and availability ). If you find a good pump and you are OK with it, then it is the right pump for you!

For the record, no cavitation issue with my pump (yet). Huum...

Good luck!

 

[Catt22]

Not really,

1. In a closed system the pressure can be way above what the pump could produce. I think you are confusing line pressure with head pressure. They are not the same thing at all. The typical small mag drive pumps are only rated at something like 12-20 ft of head which is only about 5-10 psi max. Pumping against the max head would be the equivalent of pumping with the output valve closed. ie, max pressure and zero flow rate.

2. You can easily find all the pertinent data on the head material used for most any pump. Most of the more common pumps have Ryton, Polysulfone, Polypropylene or Nylon pump heads. These materials are much different than the material used in the manufacture of the seat covers of your car. The lack of an NSF certification does not necessarily indicate that a pump is not suitable for brewing. Some pumps simply were never targeted for the food industry market and for that reason, the mfg saw no reason to go to the trouble and expense of acquiring the certification.

3. The pump heads won't explode or fail prematurely as the result of excessive pressure as they won't be exposed to any high pressure as we typically use them. It is prudent to read the pump specifications, but understanding them is just as important. Same for the pump curves. Obviously, not all of the pumps available can handle high temperatures, but if they are rated at anything like 150 F or above there should be no problems.

3. The beer itself likely contains far more "nasty' and potentially hazardous chemical compounds than anything a plastic pump head might contribute. If I was at all concerned I would get a pump with a stainless steel head. The Ryton head my pump has is good enough for me. After all, Ryton is a Chevron Phillips product. We all trust Chevron now, don't we?

4. If you want to experience the fun of cavitation, simply try to pump actively boiling water. It doesn't work very well.

5. Yes, the bottom line it is a personal choice. My only point was that the maximum working temperatures for these small magnetic drive pumps are frequently misunderstood. I'm no expert on this **** by any stretch, so please don't rely on my opinions alone. Do your own homework and come to your own conclusions.

 

[lanvp]

Not really,

1. In a closed system the pressure can be way above what the pump could produce. I think you are confusing line pressure with head pressure. They are ...

Maybe,

Items:
1. In a close loop, agree!

2. For a March or LG pump the information may be readily available. "Identical to" means not the same. Without the spec sheet you can only guess. The materials you listed are very good for thin wall molded parts. Especially when using glass filled formulation for dimensional stability, and strength (increasing the TG closer to melt point too!). These virgin materials are OK. My concern will always be with the additives to process the materials like plasticizers and other stuff to improve the flow and forming processes (for ex. BPA). The car interior was an example of the outgassing mechanism or the process of releasing "stuff" (aka is some cases VOC).

3. I can live with that...

3. (the other item 3 on the list) - It is my understanding that there are no pathogens in beer!!! OK, maybe bad taste but that is relative to the tester.

4. I haven't pump boiling water but did extensive testing pumping boiling wort from BK through CFC. I use it to sterilize it (10 to 15min cyles). Apparently, I was lucky . I will take your word on the unpleasantry of cavitation...


This have been a great discussion. Thanks for the information!

Cuzco_Brew:
Sorry of hijacking the conversation. Hope you get the pump soon. Keep us informed.

 

[Catt22]

1. Yes, in a closed loop system the pressures can far exceed what the pump can produce on it's own and the ratings are the maximum working temperature at the maximum working pressure. The temperatures can be exceeded so long as you are at less than the maximum working pressure. How much so, depends on the specific materials. IOW, it's not an issue of the materials releasing nasty chemicals at the higher temps, but one of the strength of the material.

3. I think we were talking about introducing undesirable chemical compounds into the beer from exposure to plastic components, not pathogens. I would be more concerned about the plastic used in coolers, hoses and PVC fittings etc, than I would the pump heads and related pump parts exposed to the wort, especially since most of the common pumps we use were designed as circulation pumps for domestic hot water systems.

4. It all depends. If you have sufficient positive suction head on the pump, you can pump liquids at close to boiling temperatures, but if it is actually boiling when it reaches the pump inlet, vapor pockets will enter the pump and it will cavitate. Minimally this will only cause some rattling noise and maybe cause the pump to lose its prime. Worst case it can eventually damage the pump if it goes on long enough. Fortunately, the temps drop pretty fast to below the boiling point, so it's only a minor annoyance most of the time. I used to pump near boiling water up into an elevated HLT and it just wouldn't happen until the temp dropped to about 200 F. Any restrictions on the suction side of the pump can aggravate the problem considerably. That's one of the reasons I changed to larger diameter hoses long ago. That helped a lot.

Yes, it's good to toss this stuff around. As I said earlier, I'm not an expert on any of this, so don't rely solely on what I post. Oh yeah, duh. We did sort of drift off topic some. I hope the OP finds a suitable pump for a reasonable price. It's cool that we have someone home brewing in Peru. I'm sure that's not easy to do. If it were me, I'd probably just stick with coffee and cocaine! Just joking, ya know. Too much coffee can give me the jitters.