Main drain vs skimmer - Pressure

[nameBrandon]

Hi all,

I'm relatively new to pool ownership and had shared my initial pool renovation thread here (The Great Mistake (photo heavy!) ). The pool is gunite, ~22k gallons, built-in spa, ~30 years old. Now that the pool itself is in good shape, we're focusing on the equipment. The pool company we use for the renovations (new lines, skimmers, replaster, new deck, etc..) seemed to be having trouble consistently getting the filter pump and filter to run. It would hold pressure a little bit and the filter/pump would prime and work, then eventually water would stop sloshing around the top of the filter (Sand filter, BTW) and the pressure would hang out around 2 psi. The only equipment partially working is the filter and the main filter pump. The spa jets and the booster pumps are all dead. All of the equipment is original (except the heater), so we're taking 30-year-old sunken pad with cracked and patched PVC, rusted out pumps, 30" filter that is one big egg of exposed fiberglass, etc... The company has repeatedly said they pressure tested all of the new lines multiple times and they hold pressure just fine.

This week, I had a company working for the home warranty we purchased look at the equipment (see if we can get anything replaced under warranty). These guys seemed pretty good. Right away he moved to running the filter / pump off of the main drain which he said had 100% pressure and worked fine. He said when hooked up to the skimmers as it should be, he was seeing about 85% pressure and there was a minor leak. This was already a fair bit more information than I'd gotten from the main pool contractor, and using the main drain actually allowed for consistent running of the filter, pump and heater, so we could start to use the pool a bit.

I didn't think to ask the guy, but what does that actually mean, "running off the main drain", and what does that look like differently than running off the skimmers. Is that adjusting the multiport valve in a certain way? I'm wondering if I was looking at the equipment, how I would know if it was running off the main drain as opposed to the skimmers? I'm also concerned about the new skimmer lines.. If the pool renovation company is saying they hold pressure fine, could the multiport be bad (very possible), or some other connections to those lines be at fault?

 

[ajw22]

Post pics of your equipment pad and valves and it will be easier to explain.

 

[cfherrman]

Running of the main drain would be suction only from the main drain.

What I have a real problem with is how do you make a statement of 100% pressure from main drain and 85% from the skimmer. If you haven't owned the pool for a year or two or installed the equipment and pipes new how do you know what the typical pressure should be.

My guess he was getting more pressure from the main drain only compared to the skimmer only, which means you are getting more flow from the main drain than the skimmer.

So, why more flow.....

Low water in skimmer
Plugged skimmer and/or lines
Suction side leak in skimmer lines(can hold pressure and still leak at vacuum)

 

[nameBrandon]

Post pics of your equipment pad and valves and it will be easier to explain.

See below. It's a mess.. 30 years worth of neglect, so we're definitely starting with a new pad and everything next year, just trying to make sure things are done properly for that work that has already been done.

Running of the main drain would be suction only from the main drain.

What I have a real problem with is how do you make a statement of 100% pressure from main drain and 85% from the skimmer. If you haven't owned the pool for a year or two or installed the equipment and pipes new how do you know what the typical pressure should be.

My guess he was getting more pressure from the main drain only compared to the skimmer only, which means you are getting more flow from the main drain than the skimmer.

So, why more flow.....

Low water in skimmer
Plugged skimmer and/or lines
Suction side leak in skimmer lines(can hold pressure and still leak at vacuum)

Thanks! I wish I knew more to tell you. My only guess is him looking at the gauge on top of the filter. That's the only place he could get a quantitative measurement as he didn't break out his own gear or anything. I'm assuming he saw the 10+ psi when hooked up to the main drain, and less when he hooked it up to the skimmer.. so maybe he meant 85% of what he saw from the main drain? Again, just my guess, I have no idea what I'm talking about.

 

[ajw22]

I didn't think to ask the guy, but what does that actually mean, "running off the main drain", and what does that look like differently than running off the skimmers. Is that adjusting the multiport valve in a certain way? I'm wondering if I was looking at the equipment, how I would know if it was running off the main drain as opposed to the skimmers? I'm also concerned about the new skimmer lines.. If the pool renovation company is saying they hold pressure fine, could the multiport be bad (very possible), or some other connections to those lines be at fault?

Look at the pic below. Each of your pipes has a ball valve. The rightmost pipe is your MAIN DRAIN. The ball valve on that is open. All the other ball valves on your pipes ae closed Except for the far left that is partially open.

You turn on and off the flow from your SKIMMER or MAIN DRAIN using the ball valves on the pipes. You can tell what you are running off by the position of the valve handles.

Your MPV controls your filter functions and not the flow in from the different pipes.

I do not know how someone can conclude that your skimmer line only flows at 85%.

I would run it with both your SKIMMER and your MAIN DRAIN valves open. Right now only MAIN DRAIN is open.

 

[nameBrandon]

Look at the pic below. Each of your pipes has a ball valve. The rightmost pipe is your MAIN DRAIN. The ball valve on that is open. All the other ball valves on your pipes ae closed Except for the far left that is partially open.

You turn on and off the flow from your SKIMMER or MAIN DRAIN using the ball valves on the pipes. You can tell what you are running off by the position of the valve handles.

Your MPV controls your filter functions and not the flow in from the different pipes.

I do not know how someone can conclude that your skimmer line only flows at 85%.

I would run it with both your SKIMMER and your MAIN DRAIN valves open. Right now only MAIN DRAIN is open.

View attachment 118608

Thank you! Do I need to do anything when I open the skimmer valve (other than open the valve, I mean).. Stop the pump or anything? Anything with that Jandy valve box at the front of the filter pump?

 

[ajw22]

Just open or close the valve slowly and observe what is happening with the pump. You never want to starve the pump of water so if the pump is losing water then return the valve to its prior position.

You can stop the pump before moving valves but I find its safer observing the pump as you move a valve. If you are doing something wrong you will hear it and see it at the pump.

The Jandy valve leading into the pump has a motorized actuator on it. You have some type of automation that controls that actuator and one on the POOL/SPA return line. Both valves need to turn to draw water from your SPA and RETURN ir back to your SPA. There are ways to manually turn the actuator and valve.

What pool/spa control panel do you have?

 

[nameBrandon]

Just open or close the valve slowly and observe what is happening with the pump. You never want to starve the pump of water so if the pump is losing water then return the valve to its prior position.

You can stop the pump before moving valves but I find its safer observing the pump as you move a valve. If you are doing something wrong you will hear it and see it at the pump.

The Jandy valve leading into the pump has a motorized actuator on it. You have some type of automation that controls that actuator and one on the POOL/SPA return line. Both valves need to turn to draw water from your SPA and RETURN ir back to your SPA. There are ways to manually turn the actuator and valve.

What pool/spa control panel do you have?

Thank you again! I think the only thing I've noticed when things don't seem to be working properly is the lack of water running through the top of the filter.. so I guess I'd just look out for that?

Here's a shot of the panel. It's an Aquadyne circa 1989.

 

[ajw22]

I don’t know sand filters that well. Have you opened the filter to inspect the sand and laterals?

On your pool panel there is writing that says:

“A” code
2 -light
4 - booster
8 - spa mode

Do you have a control panel somewhere inside that the 2, 4, 8 refers to?

Post a pic of the page on the inside of the door.

 

[nameBrandon]

I don’t know sand filters that well. Have you opened the filter to inspect the sand and laterals?

On your pool panel there is writing that says:

“A” code
2 -light
4 - booster
8 - spa mode

Do you have a control panel somewhere inside that the 2, 4, 8 refers to?

Post a pic of the page on the inside of the door.

I don't believe there's any other control panels for the pool. There is something in the lower right, outside of that panel box, I'll have to see if perhaps it contains a switch or something next time I'm over there. This is the best I can get your for now, we're not living there yet (interior is almost done being renovated) so these are all from existing photos I've taken.

 

[ajw22]

There is a black wire coming out of the side of the JVA2400 actuator. When you can, follow that wire and see what box it is connected to. Post some pics of where it is connected.