Hello everyone!
I have a spa "jets" issue that I was hoping to get some help with.
I have a client with a pool/spa combo with a VSP. The jets (7 of them) are on the spa return manifold and are opened by a valve actuator. There is a cut "air" line (2" stand pipe with a wedge cut out) to mix with the spa jets, but has no air blower.
When the jets are turned on they only get about 6"-8" into the spa, and the air is mixing real well. As they continue to run the air mixture gets less and less until there is no more air, and only water returning.
I waited until the air stopped,but jets were still on. I then removed one nozzle and from that removed nozzle, that single line was working better than I've ever seen. Shooting out about 2 feet, with perfect air. The other 6 were just pushing less water flow, and no air.
I have adjusted the 2HP VSP from 2750 rpm's to both higher, and lower rpm's but the results are the same.
The current nozzles are 5/8" bayonet style with 1/4" openings
My questions are:
1. Is air getting backed up in the air channel because of too much back pressure?
2. Will switching to nozzles with larger openings allow the jets to push out further that 6" and not stop the air from mixing?
I thank you in advance for your responses and advice.
Replies
Scott
There are so many possibilities with this issue.
Is the pump for the jets a dedicated type or is it a shared pump with the filtration system?
Do you know the plumbing configuration for the spa jets:?
-Pipe sizing on both suction and return
-Sch.40 Rigid or flex
-Pipe layout-looped configuration
-Brand or exact style of jet
Spa jets generally have a range of required GPM to work properly-10-12 for each jet.
They will work properly provided on initial plumbing layout the pipe is sized properly to deliver water to the jets on the return as well as providing a large enough suction line. If these initial factors are not met, they will not work at their maximum.
Spa jets need an even flow to each by creating a looped plumbing layout where as water is introduced in 2 points in loop equidistant from each other. Your jet return line from the pump is larger then the manifold. Once at the looped manifold, it's reduced in size to the jets body size. Essentially a large supply is brought to the spa.
I will see if I can find and post a typical looped plumbing layout for a visual.
The suction line is just as important. Without the properly supply to the pump, you will never achieve proper jet action. I tell my clients if the pipe suction is too small, it's like sucking water through a cocktail straw-not enough supply.
We use Sch. 40 rigid only. Absolutely no flex/spa hose.
Just shootin' from the hip here, it sounds like there is too much back pressure and it's causing the air to stop. A venturi system on a jet allows air to be drawn as the water passes through the jet. This will work fine as long as the water is getting through.
If the pump is a shared filter/jet pump, when the filter gets dirty it will create back pressure resulting in little or no jet action and certainly no air bubbles.
I still see a lot of these set ups. The nationwide builders at the time (lates 70's and into the 80's) did this to basically save money. Customers got a pool/spa combo as an upgrade(and paid for it) but they had no idea what they were missing.
2 hp pumps on a 48SF DE filter destroyed grids and cost more to operate.
If it allows, a separate jet pump is the preferred set up. It's sounds however you have an existing set up and basically stuck with what you have short of ripping things apart and starting over.
I guess alternating nozzles and flow on the pump is about the best you can do at the moment. Fortunately the VSP gives you some advantage to dial-in an acceptable flow.