Check valve between filter and heater?

[frankml1]

Hi all, I’m currently redoing my equipment pad and noticed that the manual for my filter (Pentair Triton TR100C) states that a check valve must be installed between the filter and the heater to prevent damage to the filter. I had already planned on installing a flowvis check valve directly after the pump (to maintain suction when powered off) and a standard check valve downstream the Mastertemp 250 heater (as part of my heater bypass and to have protection between the heater and my IC40 SWG). I‘d prefer to keep the check valves to a minimum, so I am wondering what your thoughts are on Pentair’s filter valve recommendation, and if any of you have felt the need to install a check valve between your filter and heater. Thanks!

 

[Ticojpunk]

Good question. Saw the same thing in my Aqua Comfort heat pump manual. I noticed my pool installer did not install a check valve or mention it. I checked with him and he said no need. I checked with my local pool store (really big store in my area) and they also said no need. Not sure what to think on it. I don't see how a check valve could HURT, though everything is hooked up and not leaking and I always hate to introduce another component in the chain once everything is running well.

 

[1poolman1]

Hi all, I’m currently redoing my equipment pad and noticed that the manual for my filter (Pentair Triton TR100C) states that a check valve must be installed between the filter and the heater to prevent damage to the filter. I had already planned on installing a flowvis check valve directly after the pump (to maintain suction when powered off) and a standard check valve downstream the Mastertemp 250 heater (as part of my heater bypass and to have protection between the heater and my IC40 SWG). I‘d prefer to keep the check valves to a minimum, so I am wondering what your thoughts are on Pentair’s filter valve recommendation, and if any of you have felt the need to install a check valve between your filter and heater. Thanks!

That is a carry-over from the days when pool heaters had heavy cast iron or cast bronze headers and huge firewalls that retained a lot of heat after the heater and pump were turned off as most people would not properly cool a heater before shutting the pump off. That heat would then migrate into the plumbing and cause a lot of damage to anything plastic (PVC). Newer system, especially those with composite headers, fiberglass fire-box insulation, automation and their cool-down cycles, don't usually have that issue. If you don't have automation, be sure to cool the heater anyway (run the pump about 5 minutes after shutting the heater off) just to be sure. If you have been using a spa, don't just turn the valves to pool, the cold water can cause thermal shock to the heat exchanger. The manufacturers will tell you (if you ask) that a properly cooled heater will last at least 30% longer than one that isn't.

 

[frankml1]

Thanks, appreciate the responses.

 

[JamesW]

the manual for my filter (Pentair Triton TR100C) states that a check valve must be installed between the filter and the heater to prevent damage to the filter.

Can you show the exact quote that says that a check valve must be installed?

 

[JamesW]

If the manual requires or recommends a check valve, then you should use one.

You should use a cooldown period in any case.

 

[frankml1]

Here is the exact wording from the manual.

1. When installing backwash lines, it is recommended that a vacuum breaker be installed on installations where the backwash line length exceeds 40 ft. or the backwash line discharges more than 10 ft. lower than the surface of the pool. Alternately a vacuum break pit should be provided.
2. A check valve is recommended between the filter and heater to prevent hot water “back-up” which will damage the filter and valve.
3. The maximum operating pressure of the unit is 50 pounds per square inch (psi) and 75 pounds per square inch (psi) for the Triton HD model (only). Never operate this filter above these pressures or attach a pump to this filter that has more than 50 psi shut off pressure or 75 psi shut off pressure for the Triton HD model (only).
4. Never install a chlorinator upstream of the filter. Always locate downstream and with a check valve between the chlorinator and filter.

 

[frankml1]

If the manual requires or recommends a check valve, then you should use one.

You should use a cooldown period in any case.

I suppose I could always move the FlowVis between the filter and the heater and forego the check valve I had planned after the pump.

 

[Dirk]

Flow is constant throughout the system (as long as there are no weird bypasses), so the FlowVis will read the same in either location, even after the heater. Similarly, a check valve before or after the filter will be just as effective to "maintain suction," presuming you meant keeping the water in the plumbing from back-flowing into the pool through the suction-side plumbing. As long as nothing is leaking, a check on either side of the filter will do that.

And no check valve is needed between the heater and the SWG. That is also a "throw-back" to when tab-feeders were located where your SWG is now, to keep "nasty" tab water (acid and chlorine) from drifting from the tab feeder backwards into the heater while the pump is off. That is what #4 means by "chlorinator." That refers to a tab feeder, not an SWG. An SWG doesn't leech anything when it is off, and even if it somehow got powered on while the pump was off (or malfunctioning), the SWG's flow sensor wouldn't allow it to produce chlorine.

So if extra components, or extra check valves in particular, are a concern, you really only need one: the FlowVis right where the filter manual wants one. You don't really need two, and you certainly don't need three.

 

[JamesW]

It says recommended, not required.

You should not need it if you have a cooldown period.

If there is a problem that they blame on the lack of a check valve, they might deny a warranty claim if you make one.

 

[Dirk]

If there is a problem that they blame on the lack of a check valve, they might deny a warranty claim if you make one.

And that's the real reason to put a check where they "recommend" one. Your FlowVis between filter and heater would satisfy both #2 and #4 of their warranty-busters.

 

[Newdude]

If there is a problem that they blame on the lack of a check valve, they might deny a warranty claim if you make one.

And that's the real reason to put a check where they "recommend" one

Warranty tech : crud we can't deny the claim for lack of a check valve. Guess we'll have to use something vague and unprovable. *checks clipbord*.... ahhhhhh. Here we go !!! Poor water chemistry.

 

[JamesW]

Here are just a few reasons/excuses to deny the warranty.

Chlorine over 3.0 ppm.

Did not register the warranty within 60 seconds of installation.

Lack of a check valve.

Nitrates over 10 ppb.

Not professionally installed.

pH not kept at 7.5 +/- 0.001.

Phosphates over 10 ppb.

Pool is salt water.

TA not kept at 80 to 120 ppm.

TDS over 100 ppm.

Water too dry.

Water too wet.

 

[frankml1]

Flow is constant throughout the system (as long as there are no weird bypasses), so the FlowVis will read the same in either location, even after the heater. Similarly, a check valve before or after the filter will be just as effective to "maintain suction," presuming you meant keeping the water in the plumbing from back-flowing into the pool through the suction-side plumbing. As long as nothing is leaking, a check on either side of the filter will do that.

So if extra components, or extra check valves in particular, are a concern, you really only need one: the FlowVis right where the filter manual wants one. You don't really need two, and you certainly don't need three.

Thanks, I didn't realize a check valve after the filter could be effective in maintaining suction, so that is where I will put it.

 

[frankml1]

Thanks for all the information, I will put the Flowvis after the filter to satisfy multiple recommendations and the only other check valve I plan to use is for my heater bypass. Is cool down something I need to program into my Pentair automation or is that part of the heater's programming?

 

[Dirk]

Thanks, I didn't realize a check valve after the filter could be effective in maintaining suction, so that is where I will put it.

The only exception is when you clean your filter, at least with a cartridge filter, I don't know if this applies to backwashing a sand filter, but it would apply if you disassemble a sand filter. As soon as you disassemble the filter, you "break the seal" and that would allow air into your plumbing. Then water would backflow out of the pump and back into the pool. A check valve in front of the filter would prevent that. A check after the filter would not.

When I clean my cartridge filter, I crack the filter's pressure valve and open the drain at the bottom of the filter. All the water drains out of the filter onto the ground. But my FlowVis is before my filter, so if that filter cleaning action would release crud back into the pool, I wouldn't know. I guess you'll know the first time you try it! But you could prevent that by opening up the pump basket and temporarily blocking the pump's inlet pipe with just about anything, an expansion plug or even a rag. (Just don't forget to remove it before restarting the pump.)