Why does my spa drain?
This article will focus on finding the reason(s) a spa (in a pool with
connected spillover spa setup) would drain after the system is turned off and
how to fix it. Written by www.WCPandS.com
1 - Incorrect valve position
The most common reason for a spa to drain is because of an incorrect
valve position. This also happens to be the easiest to fix.
Since there is no industry standard setup, below is a picture of the
most common suction and return pipe setup. Your system may differ but the
principals are the same. (Click on any picture to enlarge)
Suction side (directly in front of the pump):
There are usually two moveable valves on the suction side for selecting
between pool and spa. Some, however, have another next to that on the pool side
for selecting between the skimmer and pool cleaner.
Return side (either immediately coming out of the filter or immediately
coming out of the heater if one exists):
There is a valve to select between pool return and spa return on the
return side.
A brief note on valve actuators:
The pictures in this example have valves with electronic actuators on
them.
Automatic pool controllers use the actuators to move the valves to
change between different filtering modes i.e. Spa mode, pool mode, spa fill,
and spa drain. Below are a few examples of automatic systems that use actuators.
These actuators are sitting on standard 180 degree valves.
During normal operation, both valve fronts will be pointed to “spa off”,
while the handles point to the open side (as seen in the main setup picture at the top).
These valves can be changed manually via a toggle switch either under
the actuator or behind it. Automatic controllers cannot detect if these toggle
switches are used and will not auto correct the valve position if manually
moved. Sometimes, one of these are accidently switched from being bumped, and
will need to be manually toggled back.
How the spa would drain if the
valves are turned incorrectly:
A few examples of why your spa would drain if the valves were changed
are shown below.
Note: Click on any picture to see a larger version. the blue arrows represent water flow after the system is turned off.
Note: Click on any picture to see a larger version. the blue arrows represent water flow after the system is turned off.
A - A split 50/50 water return.
The idea is to return half the water to the pool and the other half to
the spa. When the system is off, the weight of water from the spa pushes water
back though the spa return pipe and into the pool return pipe, which drains the
spa.
B - Full spa return.
This is the most common mistake and very messy for the pool. The idea is
to send all of the water from the system to the spa. When the system is turned
off, the weight of the water is pushed through the spa return line, backwards
though the filter (pushing dirt with it), backwards through the pump, and then
out though the pool suction line.
C - A split 50/50 water suction
Even with a working bypass, this will probably drain the spa when on or
off.
This will pull half the water from the pool, then the other half from
the spa while returning everything to the pool. When the system is off, the
weight of the water pushes water though the spa suction, then backwards down
the pool suction line.
D - Full spa suction
Again, even with a working bypass, this one will also probably drain
the spa regardless of whether it is on or off.
When the system is off, the weight of the water pushes water though the
spa suction pipe, through the pump and filter, then out the pool return line.
On most equipment setups, the valves should be set in the “Spa off”
position.
2 - A bad check valve
When working correctly, check valves are inline devices that allow
water to flow in only one direction. The most common use of these is on a
bypass pipe between the pool and spa return lines.
This is done so that when the system is in pool mode (Spa
suction/return off), a small amount of water is allowed to flow in to the spa
to keep the spa water moving.
There are many different models of swimming pool check valves and below
are pictures of a few different variations.
Some have the option to remove the check valve with quick release
unions or a few screws; this is helpful if the problem happens to be an object
stuck in the flap or simply replacing a broken flap.
Others will need to be cut out from the system and be replaced with new
check valves. These units are cheaper than their removable counter parts. I
would never install or recommend a check valve that did not have a removable
flapper since it is common for a check valve to fail.
3 - A leaking valve
This one is less common but needs to be checked if all of the above has
been already been checked and confirmed to be working properly.
There are rubber gaskets inside of each selectable valve. If this
seal/gasket fails, water will flow freely from the spa into the pool.
To replace them, the insides of the valves will need to be replaced.
These parts are not a universal size, so you will need the exact make/model and
pipe size to replace these.
4 -A cracked pipe or plaster
The most difficult to find and costly to fix is a cracked pipe or
cracked plaster. In this case, the water leaving the spa will not return to the
pool. Instead, the water would be lost underground. There are various companies
that can detect underground leaks without unearthing the pipes. One that we
have used in the past is “American Leak Detectors.”
(New)5 -A faulty 3 port valve seal
Although unlikely it is possible for water to flow through a closed three-way valve with or without an actuator attached. This happens when the raised rubber seal breaks or becomes deformed, allowing water to flow past a closed seal. On a perfectly working system, when the system is turned off there should be no sounds coming from the pipes.
I have only seen this happen twice and each time was with a Waterway TruSeal 3 port valve.
Below is a picture of a valve that allowed water to pass through even when closed.
The rubber seal around the edge has torn.
The fix is to replace the insides of the valve. Once the screws holding the top are removed, the top plate can be pulled up and off.
A new TruSeal valve is shown below