Straight vs 90° Check Valve

[sjsoldo]

Plumbing a heater bypass. I use the Jandy valves. The angled check valve will save some plumbing. Any downside?

 

[Dirk]

Why do you think you need a check valve? If I'm picturing what you're doing correctly, then a check valve might not be needed. Is it a solar heater, or a gas heater? If you draw up a little sketch of what you're trying to do, then our experts can give you the skinny on that.

Which doesn't actually answer your question, I realize. I 90 reduces flow some amount. So does a check valve. Both together would be more resistance than just one or the other. Neither so much that it matters in the grand scheme of your pool's plumbing... I don't know of any other specific downsides...

 

[sjsoldo]

Sir, I am an avid TFP reader. The website indicates that when installing a heater bypass, a check valve should be placed on the output plumbing of the heater:

Heater Bypass - Further Reading

www.troublefreepool.com

Presumably this is to prevent backwards flow into the heater , and this appears more relevant if you have a SWG after the heater.


So, given the recommendation for a check valve, and the need for a right angle bend in the plumbing near there, I am considering either:

1) Use an ordinary elbow, and place a straight check valve after that elbow and before the bypassed flow
<or>
2) Instead of the above, use a 90 degree angle check valve which would both accomplish the 90 degree bend and the check valve function.


I was asking to see if there are any downsides to the 90 degree check valve over the straight one. Am I making sense?

FYI I have a gas heater.

 

[Dirk]

I think @ajw22 had a hand in that article. He'll be able to give you a better answer than I can. @Jimrahbe knows a lot about plumbing, too.

If you take the bypass out of the equation, a check valve is not needed between a heater and an SWG. So it's not clear to me why the bypass would change that.

And if there is water in the heater, and the three-way valve is in bypass mode, water won't backflow through the heater, there's no where for it to go. But perhaps the check valve would keep a small amount of water moving the wrong way as the valve is turned? Still seems optional to me... Do you winterize your pool? That might have a bearing.

If you want to be able to disconnect the heater (like for repair) while leaving the rest of the system active, then yes, you would need a check valve, or other isolation valve.

It's academic. There's certainly nothing wrong with having the check valve after the heater (except for the small amount of restriction it adds).

Let's see what the guys say...

(You should add your location to your profile, as where your pool is can affect the advice you get. )

 

[ajw22]

The CV in the Heater Bypass article makes the bypass work using a single valve. You close the heater in and out line using one diverter valve. Using one diverter valve and a CV prevents errors that can happen when two valves are used

 

[ajw22]

And if there is water in the heater, and the three-way valve is in bypass mode, water won't backflow through the heater, there's no where for it to go. But perhaps the check valve would keep a small amount of water moving the wrong way as the valve is turned? Still seems optional to me... Do you winterize your pool? That might have a bearing.

That only works if the heater does not leak and holds pressure. If you have a leak in the heater core you need the CV to stop the back flow of water when you bypass the heater. Without the CV the bypass is useless in many heater failure scenarios.

 

[Turbo1Ton]

That only works if the heater does not leak and holds pressure. If you have a leak in the heater core you need the CV to stop the back flow of water when you bypass the heater. Without the CV the bypass is useless in many heater failure scenarios.

When I reworked my plumbing to add the heater bypass and IntellipH, I was just about to toss the check valve that the PB had installed (they had incorrectly put in a chlorinator, instead of the SWCG cell). Fortunately, at the last minute, I thought of the above scenario, where I might need to remove the heater in order to work on it, and was able to reuse the check valve that I had.

To answer the OP's question, I am not sure that the losses matter, since you would have both an elbow and a CV regardless. As Dirk mentioned, neither is going to have much of an effect on the overall system. I would use whichever makes for a cleaner looking install.

--Jeff

 

[sjsoldo]

Now that I think about it, the primary reason for the check valve is to make the heater bypass "idiot proof". Instead of a check valve you had a second valve and turned it the wrong way, you could block the flow of water and damage your system.

 

[JamesW]

I was asking to see if there are any downsides to the 90 degree check valve over the straight one. Am I making sense?

The 90 degree check valve is fine.