2 pumps or 1

[blissville maples]

Wondering if having one large pump say 7.5 horse vs 2- 3hp has any advantages, or more disadvantage?

If one pump is down always have the other to hold some sort of vaccum on the system would be one advantage.
If one pump is already owned then only need another small pump vs one big one. (My situation)

I guess I can't really think of any major performance changing disadvantages, but that doesn't mean there aren't! Sure you'll have two circuits two switches etc but that's no biggie I don't think.

Any insight or experience appreciated
Thanks

[DrTimPerkins]

You can do this, but the two pumps would need to be fairly well matched. We have two sets of two Busch pumps set up like this. They can each operate independently or be operated while bridged together. Typically we run them in pairs that are bridged, but if one needs maintenance during the season, or one goes down for some reason, we'll close one down and let the other take the full load.

All our pumps are similar and wired the same with VFDs and pressure transducers. We also keep a spare pump so if one of the pumps craps out we can pull it out and replace it quickly.

We don't do this necessarily as a way to maximize production, but mostly because we do try to keep some research areas segregated from the production system. It just makes it easier to not have to compromise or have conflicts between research and production. However being able to bridge the pumps is helpful to both research and production due to the redundancy in case of a failure of one or the other.

An alternative I've heard is that people will have one big pump for early season. Once the leaks are all repaired and the system is tight they'll turn on the smaller pump and shut down the big one. If there is a storm or vacuum is lost for some reason, they'll switch back to the larger pump for leak checking. This is because if the system is kept really tight it doesn't require the full 1 CFM/100 taps, so a small pump is able to handle it pretty well. But the larger pump moves more air, so is good in the early season and for leak checking. This can save some $ in electricity and provides some level of backup in case one pump or the other fails.

[ecp]

In this case are both pumps plumbed together with a tee or just hooked into the releaser? I've been looking at a bigger pump or 2 pump option (undersized right now) and would like to know more. Also the whole large pump small pump idea seems silly when you can just pump a vfd on the pump and cut energy that way.

[DrTimPerkins]

In this case are both pumps plumbed together with a tee or just hooked into the releaser? I've been looking at a bigger pump or 2 pump option (undersized right now) and would like to know more. Also the whole large pump small pump idea seems silly when you can just pump a vfd on the pump and cut energy that way.

In our operation the two pumps are just side-by-side with a tee in each line with a bridge pipe and valve between them. We've set them up before so we could have one or both pump run either or both sides, but with the various options and moisture traps the plumbing gets complicated and lots of twists and turns that reduce CFM (the straighter and the bigger the pipe the better...same for air and for sap).

We don't do the small pump - large pump thing, but I know some people who do. Although the VFD can ramp down a lot, it might save some wear and tear on the big pump....although I think that most quality pumps actually do better when running continuously than not.

[blissville maples]

So basically they should be approximately around the same cfm. probably 2 identical pumps would be best for this scenario.

It doesn't sound like a bad thing. And I guess that does make alot of sense with the leaks, definitely makes it easier with more air coming through, and yes once it's tight you probably do need considerably less if you're able to stay on top of the leaks that do occur.

So over all if pumps are matched well and one isn't sucking on the other there shouldn't be much or any negative consequences to this.

[DrTimPerkins]

Correct. As long as the pumps are matched well it works.