RP4A/RPLF4A Breakdown and Explanation
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- เผยแพร่เมื่อ 1 มี.ค. 2021
- I take the RP4A (same as the RPLF4A) apart and explain the different components and some things to look for if you suspect that it may have frozen. This would be the procedure for 2" and smaller sizes.
Below are links to the major repair kits available on my webstore. Other kits can be found on our webstore. Complete assemblies can also be found on the webstore.
For clarification repair kits are specific to the 1/2" size and then the 3/4", then the 1", the 1 1/4" and 1 1/2" take the same kits and then the 2"
Also linking to the ball valve tool to turn the ball valve on and off. For small valves backflow-supply.com/products/...
For larger valves backflow-supply.com/products/...
3/4" complete rebuild kit, 4A00410 backflow-supply.com/products/...
1" complete rebuild kit, 4A00510 backflow-supply.com/products/...
1 1/4" - 1 1/2" complete rebuild kit 4A00710 backflow-supply.com/products/...
2" complete rebuild kit backflow-supply.com/products/... - แนวปฏิบัติและการใช้ชีวิต
Great video. Very informative. Thank you!
Thanks for taking the time. Concise and professional. You make a good teacher.
Nice info. I was able to diagnose and repair my RP4A with this info.
After 3 hours and taking apart almost the entire thing the problem was in the release area it couldn’t go back and forth because of some buildup cleaned it out and applied a lot of lube and the leak finally finally stopped
Applied a lot of lube where? What type of build up? I could see the need for some lube on the o-ring under the bushing on the stem but no where else. I have not seen build up keeping it from moving, but have seen a swollen, or unlubed o-ring prevent the stem from sliding through the bushing.
Feel free to call me at 801-355-6736 or email me at sean@backflow-supply.com if your issue comes back.
@@backflowsupplyslcut9394 I think it was the unlubed o- ring keeping the stem from sliding
I just want to thank Sean for this video and also his amazingly quick response to a question I had for him. His tips (and this video) were exactly what I needed to fix my issue. As a "local" here in SLC, we're grateful to have such a knowledgeable resource close by!
Thanks Gregg!
“Hi, I’m still Sean”. Lol. We have been installing more of these lately. Made in USA and a bit better price than Wilkins. Not a lot of freeze worries in our area and have been happy with the quality. So far I have only changed a CV on one and cleaned and lubed an RV on another. If I remember correctly, they were both .75” devices. Your videos are good and helpful. Thanks.
Thanks Sean! Awesome info!
God bless for your time in sharing of your knowledge!
You are welcome Russell. Thanks for taking the time to comment.
Hi Sean, thank you for the video. I won't start to see the freeze damage until the beginning of May here in the Cleveland Ohio area. I usually see a lot of cracked test cocks and inlet/ outlet ball valves as the irrigation guys need to learn how to properly winterize the device. As you know it is important to put the ball valves at a half open position to drain the water from in and around the ball including the test cocks which are ball valves. All my best from backflowjoe.
Thanks so much for comment and the reinforcing the importance of winterizing the ball valves and test cocks
This video is just what I needed to trouble shoot my back-flow preventer. Sure enough my unit froze around the relief valve. I’m seeing the spray coming from the cover sides and the relief valve stem is broken. I have a new relief valve and I’m hoping I can flatten out the cover as you’ve suggested to make this repair. If not I’ll be forking over the big bucks for a new unit. Lesson learned-pull the relief out to drain all the water out of the bottom. Thanks for posting this information Sean!
Hopefully you were able to pound it flat. You can get the new cover as an option before a new assembly.
This is a really great video and explanation.
But can this backflow preventer be installed upside down or vertically?
Thanks in advance.
No. This should not be installed upside down or vertically.
Question... What would happen if you swapped the spring for the number 1 check valve with the spring for the number 2 check valve? Would it still work as normal? Cause it to leak out of relief valve? Thanks
Dimitri, I know I answered your question in the email, but didn't realize the question was here as well, so I wanted to post the response so others saw it also...
On an RP the relief valve would not be able to shut if you switch the #1 and #2 check springs. Remember the #1 spring needs to be a minimum value of 5 psi, the #2 spring needs to be a minimum value of 1 psi and the RV spring is minimum value of 2 psi. So if you put #2 in #1 position it doesn’t allow the water to be diverted to the relief valve to close it because the #2 spring is only 1 psi and has less resistance than the RV value of 2 psi. It would open the #1 check and pass through the RV vent.
In the DC models the spring doesn’t matter as they both should be a minimum of 1 psi.
I installed a new RP4A, bled the input and I'm sure its installed in the right direction but as soon as I turn the water on it starts gushing out the bottom. The unit is brand new so what might be the problem.
Maybe you have resolved this already. But the first thing to do is to get a flow going through the backflow assembly greater than what is coming out the relief valve. I am assuming this is going to a lawn sprinkler system. Even though it is dumping water turn a zone on that will get the required flow of water and observe if it stops dumping. If it does you know there is an issue in the first check valve. If it doesn't it is an issue with the relief valve.
It is not uncommon on a new install for debris in the line, rocks, rust or other debris gets flushed into the first check. Take it apart and see if that is your issue, inspect the rubber and the seat to make sure they didn't get damaged and put it back together and turn it on again. Hopefully it doesn't dump again. But sometimes it will and it could still be more debris in the line.
I have seen a few issues with the relief valve in the last year in brand new units. So far I have not been able to determine the cause but have provided those that brought the unit from me with a new relief valve and it has solved the issue. This is rare.
You are welcome to call me at 801-355-6736 if needed. Ask for Sean.
Can I buy that socket adapter to shut off the water?
If you are referring to that tool used at 2:22 in the video, yes you can buy those to shut off the ball valves on backflow assemblies. There are three different sizes. Part numbers WV100, WV101, WV106. backflow-supply.com/collections/backflow-test-kit-accessories
HI Sean, I just found your videos on the Apollo RP4A and they are very informative and helpful. Here in SA TX we don't get many freezing days, but we did just have the first and sure enough the next day I heard gushing water coming from the vent hole. I assume there is a crack in the actual metal right? I have not taken it apart yet but will inspect tomorrow. Question- I have already shut the first ball valve off which stops the water leak, but to actually remove the entire assembly from the line I need to shut if off at the street correct? Second- I can twist the entire assembly just by hand- it's plumbed into PVC. How tight must it be once I reinstall? I assume just twist the whole assembly and remove. Correct? Once I have it off line, would you recommend changing out the PVC into metal by cutting just above ground and joining the existing below grade PVC to metal or just leaving the PVC? It is insulated at the moment. Regarding draining the lines if we have another freeze... I don't have a compressor to attach nor is there an air line currently plumbed in. So would I just open the test cocks to release pressure. Do I need to remove the relief valve and remove the spring and keep it inside once water is removed by doing so? Last confirmation- since I have killed the water at the first ball valve entering the assembly, do I need to open the test cocks before disassembling the unit? Is there still pressure on the back side of the assembly? Does that make sense? Sorry for the long response, but you are a master as it appears by the videos. Thanks again.
Samuel, I will try to answer your questions.
Yes you may have a crack in the brass. It maybe under the first check valve right in the center line going down into the relief valve area. It is also possible you have a broken component only. But if the brass is cracked it is done.
Yes, you will need to shut this off at the street before you remove the assembly. However, until you know the assembly needs to be replaced I would not remove it. You can do repairs and inspection inline.
If you do not have union nuts to take this out and it is just hard piped, you will have to cut one side of the PVC to remove it. Even though you can turn it by hand currently as you loosen one side it tightens the other side.
When you reinstall I would recommend using plumbers tape, or pipe dope, but you need to be careful with the pipe dope. So many people use to much, are sloppy with it and get it in the pipes and it blows into the backflow assembly and causes problems. I would just stick with the plumbers tape, (teflon tape) and just tighten it until it is snug with a wrench.
I am not an expert at plumbing. Someone more experienced may tell you differently, but this has worked for my projects. I have also seen the mess of the pipe dope when people bring the assemblies in after they have installed a new assembly.
It is up to you if you want upgrade these pipes to metal pipes or leave them as PVC. PVC is pretty flimsy but I do see them this way. I would at least use union nuts when you put it back in place on the pipes coming up out of the ground, regardless if it is metal or PVC pipe. I would also use a tie rod or other strong metal support to drive down next to the pipe if you are going to leave PVC and strap the metal support to the PVC pipe to give it some stability. That is up to you. If you don't have an issue just put it back to PVC.
A comment about insulation. Insulation only slows down the freezing process and delays the warming up process if you do not have a heat source with it. Eventually it will become the same temperature inside the insulation as it is outside if there is no heat. It might be helpful for an overnight dropping below freezing and warming up the next day above freezing, but if it stays cold enough long enough it will still freeze.
Regarding draining the lines, just opening the test cocks will drain most of the water out of the backflow but not the lines. I would still recommend taking the relief valve cover off and removing the diaphragm assembly, make sure the water is out and you can put it back in place and put the cover back on.
If you redo the system you may want to install an air compressor fitting after the backflow to blow your system out in the future.
Lastly, when you open the assembly, with the #1 ball valve shut off it is a good practice to open the test cocks to drain the water out of the assembly. But in this instance where the water is already draining out it might not make a difference.
If you have more questions you are welcome to email me at sean@backflow-supply.com or call 801-355-6736.
Thanks!
Hi Sean, there's water coming out of my relief valve from where the diaphragm sits. It's not a mist as you noted, but more like a spray. Water is also coming out of the vent. Is that repairable with one of your rebuild kits?
If I understand you correctly the water is coming from in between the relief valve cover and the body of the assembly is where it is spraying from? And then leaking out of the vent opening as well. Did this freeze? If so you may need to do more checks on the body of the assembly to look for any types of fractures on the outside of the body and more importantly behind the number one check on the inside down the center line of the body. If the body is not damaged then yes repair kits will most likely be needed and can repair it. You may also need to inspect the relief valve cover plate to see if it is bowed slightly which is why you have the spraying coming from there, if I understood your question correctly. You might be able to flatten the cover plate to resolve that.
If you need to talk more and need more clarification please call me at 801-355-6736 or email me at sean@backflow-supply.com
The crack you show inside the check valve @ 13:00, is it supposed to be there? Or is it a freeze crack & needs replaced?
That is a freeze crack. It can't be repaired so you would have to replace the assembly. Even the fractures I show on the outside of the body would most likely require replacing the assembly as this is an indication the body has warped and the body is no longer true and the o-rings can't seal as they should allowing water to get by them instead of sealing it.
Shut off SOV#2 is all you forgot.
What did I forget about the #2 SOV??
What an awful design. After all that work and parts, after that valve has been in service for a few years it will likely not reassemble well.
Solution: Replace that assembly with a Wilkins 975XL
Good video though.
Thanks Lunker. However, while this assembly does have some issues, the reality is they all do. I have never had problems with the assemblies going back together well unless it has had some damage to the body.