Spa issues

[Gourockian]

I have a small 2-jet spill-over spa which does not have a return check valve, so when the pool pump motor shuts off, the spa water settles to the same level as the pool. I'm not so worried about that as it doesn't take too long to fill up again.

My main concern is that when emptying the spa for cleaning, air is sucked in through the drain when the water is removed and gets trapped in the return line. This means that the next time I open the spa drain valve, I have to do it gradually and leave the main pool drain fully open, to reduce the amount of air being pulled though the pump. This, of course, increases the time taken to empty the spa. I've never removed the spa drain cover but wondered if there should be some kind of check valve installed there to prevent air intake?

Should this air in the drain line normally be purged during the emptying of the spa? The reason I ask is that this never happens but as soon as the spa drain valve is closed, the air disappears from the pump strainer basket. This leads me to suspect that there is also an air leak somewhere in the spa drain line.

Another problem seems to be that I probably have a leak in one of the two jet supply lines as one seems to be weaker when refilling the spa. I've also noticed a gradual drop in pool level when the spa is running so have emptied it for now. It looks like I'll need to call in a leak detection $$ervice.

Finally, the spa has two 3/4" air pipes connected to the jet lines but as the spa is seldom used, I'm proposing to cap them off. They don't work as it is, even though I've cleared them out using a Harbor Freight Power Plunger (handy tool). I suspect the reason they don't work is that some years ago, the diverter valve went bad and instead of getting a new one, I inserted a regular tee nearer the filter to split the output between the pool and spa. A 2-way valve on the spa line controls/shuts off the flow but as the pool line is permanently open, the spa jets do not have the same pressure as before. I'll probably get around to replacing the diverter valve at some point but may have to re-jig the plumbing a little. Is capping off the air lines likely to cause any problem in relation to the operation of the jets, apart from having no air bubbles? I plan to recoat the concrete deck with Encore Coatings Cool For Pools, which will slightly raise the deck level so would want to cap them in advance.

I apologize if some or none of the above makes any sense but would welcome any comments or advice.

Regards,

Al

 

[1poolman1]

I have a small 2-jet spill-over spa which does not have a return check valve, so when the pool pump motor shuts off, the spa water settles to the same level as the pool. I'm not so worried about that as it doesn't take too long to fill up again.

My main concern is that when emptying the spa for cleaning, air is sucked in through the drain when the water is removed and gets trapped in the return line. This means that the next time I open the spa drain valve, I have to do it gradually and leave the main pool drain fully open, to reduce the amount of air being pulled though the pump. This, of course, increases the time taken to empty the spa. I've never removed the spa drain cover but wondered if there should be some kind of check valve installed there to prevent air intake?

Should this air in the drain line normally be purged during the emptying of the spa? The reason I ask is that this never happens but as soon as the spa drain valve is closed, the air disappears from the pump strainer basket. This leads me to suspect that there is also an air leak somewhere in the spa drain line.

Another problem seems to be that I probably have a leak in one of the two jet supply lines as one seems to be weaker when refilling the spa. I've also noticed a gradual drop in pool level when the spa is running so have emptied it for now. It looks like I'll need to call in a leak detection $$ervice.

Finally, the spa has two 3/4" air pipes connected to the jet lines but as the spa is seldom used, I'm proposing to cap them off. They don't work as it is, even though I've cleared them out using a Harbor Freight Power Plunger (handy tool). I suspect the reason they don't work is that some years ago, the diverter valve went bad and instead of getting a new one, I inserted a regular tee nearer the filter to split the output between the pool and spa. A 2-way valve on the spa line controls/shuts off the flow but as the pool line is permanently open, the spa jets do not have the same pressure as before. I'll probably get around to replacing the diverter valve at some point but may have to re-jig the plumbing a little. Is capping off the air lines likely to cause any problem in relation to the operation of the jets, apart from having no air bubbles? I plan to recoat the concrete deck with Encore Coatings Cool For Pools, which will slightly raise the deck level so would want to cap them in advance.

I apologize if some or none of the above makes any sense but would welcome any comments or advice.

Regards,

Al

If the main drain in the spa is uncovered (no or very little water) the pump will pull air regardless of what other suction line may be open to it as well.
Air does not get trapped in the lines. As soon as water is forced into the plumbing it is expelled into whatever body the line goes to or is pulled into the plumbing and then get to the pool.
If there is a suction leak air will continually be pulled in. That is a separate issue.
If there is no way to stop the spa from draining with the pump off the plaster will continually be uncovered at the same time. Not good for the plaster.
Blocking the air line will not affect the water into the spa.

 

[Gourockian]

If the main drain in the spa is uncovered (no or very little water) the pump will pull air regardless of what other suction line may be open to it as well.
Air does not get trapped in the lines. As soon as water is forced into the plumbing it is expelled into whatever body the line goes to or is pulled into the plumbing and then get to the pool.
If there is a suction leak air will continually be pulled in. That is a separate issue.
If there is no way to stop the spa from draining with the pump off the plaster will continually be uncovered at the same time. Not good for the plaster.
Blocking the air line will not affect the water into the spa.

Hi, thanks for your reply. Yes, I understand about the air being sucked into the drain when the spa is emptied but I don't know how that can be avoided, unless there is some device (checkvalve?) that can shut down the line when the water level in the drain sump drops.

I also understand that air does not normally get trapped in the lines due to water flow but if air is sucked in after emptying the spa, that air has nowhere to go after the drain valve near the pump is closed. It is still in the drain line after refilling the spa, as there is no water flow through it until the next drain 'cycle'. That volume of air is very evident as soon as I open the valve again but gradually reduces to a few bubbles due to the suspected air leak.

At the moment, I'm not too concerned about the plaster of the spa being damaged as both it and the pool require to be completely resurfaced. However, I will probably have to fit a checkvalve to prevent the water level dropping at some point in the near future. As far as I can tell, it's draining back through the returns and into the pool.

Thanks for confirming about blocking the air lines.

Regards,

Al