CV spouts or CV spout adapters?

[whity]

We have sureflo vacuum systems in our 4 bushes. We will be putting new drops and spouts this season. Should we consider CV spouts or the CV spout adapter?

[n8hutch]

Provided that you have 3 feet or longer Drops I don't think there is much benefit to using a CV spout with a new drop line. I would just use a disposable seasonal spout. If your going to go the 2 piece route, check valve / stubby adapter. Then you may want to go with a stubby and a non cv spout for the first year. Unless of course you don't care about the money saved.

[DrTimPerkins]

Nate is correct. With brand new drops there is little to be gained by using CV spouts or adapters. They will provide a very slight benefit in sap yield the first year which is likely to be not worth the added cost. In subsequent years the difference in yield (and net economic benefit) increases.

[S.S.S]

Definitely use the stubbys either way you go. You will thank yourself later.

[Biz]

I think it can be a different situation when using the small Shurflo pumps, depending on how they are controlled, and the CV's may help. These small battery operated pumps usually get turned off at night. When the pump stops and there is non-frozen sap in the line there is an amazing amount of sudden backflow, which will contaminate the top hole. The CV taps should reduce the effect.
The other thing that can be done is to wait until the lines have frozen before turning off the pump to eliminate backflow, but this is tough to do in reality. And it needlessly discharges the battery, if keeping it charged is a concern. I know last season I had a line on a Shurflo pump which got turned off every night. The drops were not fresh, I didn't use CVs, and the line completely stopped running a week before a gravity line right across the road, 30 ft away. I blame it on the back flow but the 3 year old drops may have had an effect too.
This coming season I will be using CVs with new drops, and my new controller will wait for sap flow and vacuum level to drop before turning off the pump, which should all help. Will be interesting to see how it works out.

Dave

[Super Sapper]

I use a temp. controller on my lines with shurflo pumps to turn them off just after the line freezes. I have been swamped the last couple of years at the end so my lines sit with sap in them for a couple of weeks at the end with no freeze and stuff does start to grow. New drops with seasonal spouts actually are cleaner than the CV spouts when I get around to pulling taps. The CV spouts do help on 2 plus year drops but I have not seen any problems with seasonal spouts on new drops. I have gone to all 3/16 lines as the ones on a slope get the added natural gravity but the ones on flat ground just seem to run better than the 5/16 if you have a pump on the line.

[Sapmanandrobbin]

Where can I find CV spouts for 3/16 drops? Thanks

[DrTimPerkins]

New drops with seasonal spouts actually are cleaner than the CV spouts when I get around to pulling taps.

That is normal. CVs were designed to reduce movement of contaminated sap from used droplines back into the taphole (backflow). They do not protect the dropline from contamination or keep them clean. In general, the majority of backflow is on the order of a few inches (which is why new spouts work fairly well). With some regularity, backflow can also originate from a foot or two away (which is why new drops with new spouts work well). On rare occasions (hopefully), backflow can result in sap moving from 10' or more away (which is why a totally new lateral line system works best).

3/16" lines are a bit different. Because of the small diameter, the same amount of vacuum differential (due to a leak, releaser dump, shutting off pump, etc.) will move sap MUCH further back into the system toward the taphole. New spouts don't seem to be nearly as effective. Droplines help for most occurances of backflow, but not quite as well as with 5/16" lines. We'll be running more experiments this coming spring to see which sanitation strategies are most beneficial (both in terms of sap yield and net profit).

To answer another question, Leader Evaporator now makes a stubby with 3/16" tubing connection to use with CV adapters - either the original or the newer clear polycarb versions.

[n8hutch]

Currently most guys are using a 3/16 tee fitting that has a 5/16 barb on the side that would lead to your drop, a 5/16 drop line and a 5/16 cv spout.

I have been told that a 3/16 cv spout is coming. I think that they would be available from Leader first because I believe they have a patent and or the rights to the patent.

I am going to convert all of my 3/16 Drops this season to 5/16 and I will use a clear polycarbonate seasonal spout, next year I will try the CVs

[Biz]

Forgot to mention, my lines and drops were all 3/16" last year so backflow was more of an issue, as Dr. Tim suggests. I am going with the 3/16 tees with 5/16" drops and CV's next season like Nate mentioned. Tackling the problem from all angles! Will be interested in seeing that the sanitation strategy testing shows.