Question about fluctuation water pressure

[slash007]

I put a pressure gauge on my back flow device to monitor incoming pressure, and notice that it intermittently drops from 55 to about 25 psi while someone is washing, but only for about a second. It holds steady around 55psi when nothing is going on, but during any activity, it drops to 25 or so for about a second then right back up. Does this probably every few seconds. Would the incoming water be the issue, or my equipment? The backflow device is also constantly running out a little water when anything is in use. Also, I notice that everytime the hydrominders fill up, as soon as they stop, the back flow device spits out water. Thoughts?

 

[cwguy.com]

Maybe a vent port? on your backflow preventer is stuck open.... crap in it or just wear?

I have no clue about the pressures.... but it might be crap in the backflow preventer also? I believe the only why to test the pressure is to compare with readings before the backflow preventer.

 

[MEP001]

If your backflow preventer is leaking, it's not working right. It sounds like it's not recovering quickly enough to a change in the pressure on the downstream side. I would guess the sudden drop corresponds to a float valve opening.

 

[2Biz]

Is there any cast iron in the piping coming in to your wash? Ever heard of galvanic corrosion? I have a 2" main coming into my wash. The copper main was connected to the brass 2" meter with cast iron flanges. The 2" copper pipe was restricted down to about 3/4" in the area of the flanges due to galvanic corrosion. I was lucky to figure this out. It would have caused me lots of problems down the road!

 

[Randy]

A RPV “Reduced Pressure Valve” will drop the water pressure about 10-15psi if it’s working correctly. If it’s leaking from the vent it needs to be cleaned, rebuilt or replaced. Most of them are rebuilt able as they have stainless steel seats. Take the check valves out and inspect them for any debris, if the seals are questionable you can sometimes take the rubber off the check valve, turn it over and reuse it. Disassemble the diaphragm, looking for any debris or tears the diaphragm. There are many different brands and model RPV they all function the same way, these are just general suggestions.

 

[slash007]

I will check to see what the incoming piping is, but I see all brass in the equipment room I think. Just need to check how it comes in exactly. Last year I had an issue with the back flow running water all of the time, even when not in use. I bought a rebuild kit and changed everything. The leaking stopped, but went back to leaking whenever it's in use. It is a significant amount of water, there is a always a trail of water down to my drain and a big circle around the back flow.

 

[Randy]

It sounds like you might have some debris inside of the back flow assembly. When was the last time it was tested and inspected by a state certified backflow tester?

 

[2Biz]

Take a magnet and check all pipes, flanges, and fittings to make sure there is no steel/cast iron in the incoming supply...

 

[slash007]

It sounds like you might have some debris inside of the back flow assembly. When was the last time it was tested and inspected by a state certified backflow tester?

It is inspected yearly. Current inspection just became due, so I will have that done soon.

I will check the incoming supply, but it looks to be all copper inside the ER. I had a lot of trouble with galvanic corrosion a few years ago, so I got rid of all the galvanized piping everywhere in the wash.

 

[Randy]

It is inspected yearly. Current inspection just became due, so I will have that done soon.

If it's leaking it won't pass the inspection. What do they charge to test them?

 

[slash007]

If it's leaking it won't pass the inspection. What do they charge to test them?

$75. Been leaking when running for years, always passed the pressure test. Does seem worse now.

 

[cwguy.com]

$75. Been leaking when running for years, always passed the pressure test. Does seem worse now.

Have you ever tried inspecting the check valves? It will probably be an easy fix.... like cleaning a large solenoid.

Do they actually see your preventer and know it leaks?

 

[slash007]

Have you ever tried inspecting the check valves? It will probably be an easy fix.... like cleaning a large solenoid.

Do they actually see your preventer and know it leaks?

I did put in a complete rebuild kit last year, so I am familiar with it. I should have taken it apart yesterday since it was raining, but have been focused on getting my new stand/weep system working before the freeze hits tomorrow. I will take it apart next rainy day.

 

[cwguy.com]

I did put in a complete rebuild kit last year, so I am familiar with it. I should have taken it apart yesterday since it was raining, but have been focused on getting my new stand/weep system working before the freeze hits tomorrow. I will take it apart next rainy day.

I see I missed that. Well was there a lot of crap in it? If not why not just purchase a new one?

Good thing is.... the backflow preventer weep works! LOL

 

[slash007]

With it raining this morning, I took by backflow preventer apart to check it. Everything was clean and seemed to be sealing properly. All parts are less than one year old and the brass doesn't seem worn, so what else can I check for/fix that would cause it to spit water every time a hydrominder fills and stops or the weep kicks on and off?

 

[Randy]

What size and manufacture is it?

 

[slash007]

1.5" Wilkins 975XL

 

[slash007]

Anyone ever had to do this?

Problem- Cause Should valve be replaced?
Solution
A.
Valve spits periodically
from the vent.
A.1
Fluctuating supply pressure.
No
A.1
Install a spring-loaded, soft seated check
valve immediately upstream of the device.
A.2
Fluctuating downstream
pressure.
No
A.2
Install a spring-loaded, soft seated check
valve downstream of the device as close
as possible to the shutoff valve.

 

[cwguy.com]

With it raining this morning, I took by backflow preventer apart to check it. Everything was clean and seemed to be sealing properly. All parts are less than one year old and the brass doesn't seem worn, so what else can I check for/fix that would cause it to spit water every time a hydrominder fills and stops or the weep kicks on and off?

Bypass the backflow.... if that fixes the problem replace the backflow. Or just purchase a new backflow?

I had a similar problem and I purchased a rebuild kit which did not fix the problem. I then just purchased a new backflow. It fixed my problem.

 

[Randy]

When you installed the rebuild kit, which kit did you use? the rubber parts kit or the complete kit that includes everything inside the backflow unit.