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Old 07-30-2010, 10:47 AM
surewin surewin is offline
 
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Default Sprinkler

Wet Sprinkler System

System side pressure and supply side pressure are the same? Do you guys know what's causing this? Also, it's equipped with a backflow preventer. I suspect this might be the cause but wanted other opinions. Also, what is the solution? conducting a 2 inch drain test?
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Old 07-30-2010, 03:47 PM
CKL958 CKL958 is offline
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Quote:
Originally Posted by surewin View Post
Wet Sprinkler System

System side pressure and supply side pressure are the same? Do you guys know what's causing this? Also, it's equipped with a backflow preventer. I suspect this might be the cause but wanted other opinions. Also, what is the solution? conducting a 2 inch drain test?
If an attempt has been made to bring the system pressure up and it does not rise, you have a leak. I wouldn't so much suspect the backflow as a leaking drain valve, or a gasket on the flapper not seating properly. The backflow is on the city side of the system - it will have no effect on the building side of the system holding pressure.
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Old 07-30-2010, 06:35 PM
infernobuster infernobuster is offline
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A few things i would check ..

- a possible leak at the inspector test site
- a leak in the system itself
- bad jockey pump or bad jockey pump lines
- faulty gauges ( they have to be swapped out every 5 years)
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Old 07-31-2010, 12:36 PM
sugar sugar is offline
 
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is there an alarm valve or just a manifold with a flow switch and test and drain? New or old system??
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Old 07-31-2010, 04:32 PM
gfd31 gfd31 is offline
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What is the "system pressure" supposed to be?

It is possible to have both the "city pressure" and the "system pressure" to be the same, or relatively close.

If there was a leak, or even a problem with the backflow preventer the system would have "flow" and the alarm should be sounding, and if it's connected to a fire alarm system you should have either a supervisory or a trouble on the FACP at the very least.
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Old 07-31-2010, 05:48 PM
CKL958 CKL958 is offline
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Quote:
Originally Posted by gfd31 View Post
If there was a leak, or even a problem with the backflow preventer the system would have "flow" and the alarm should be sounding, and if it's connected to a fire alarm system you should have either a supervisory or a trouble on the FACP at the very least.
Flow switches generally wouldn't trip for water travelling backwards in the system. They are a spring return paddle that closes contacts when pushed. Therefore, water travelling towards the city would be pushing back to the "normal" position, and would not cause an alarm.

In a system that utilizes a pressure switch on the alarm line to detect flow, the main alarm valve would have to be open to allow water into the alarm line to create an alarm.

The backflow would be the absolute last place I would be looking. The pressure has to leak through the alarm valve to pass back into the city supply.
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