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A building pressure valve that couldn’t be adjusted.
City water reached a Langley condo building at 110 psi. The main pressure-reducing valve was supposed to bring that down, but it had stopped responding. We tried a new pilot valve first, then replaced the whole valve when it failed completely.
City pressure was 110 psi. The building was getting 90.
A pressure-reducing valve (PRV) lowers high city pressure to a safe level for the building. Here, city pressure was 110 psi and the building was seeing 90 psi, which is hard on fixtures, valves and appliances.
We shut the main valve and adjusted the low-flow valve to 63 psi, but adjusting the main valve’s pilot did nothing. The pilot was already turned all the way and its spring wasn’t working, so we quoted a new pilot valve.
A new pilot didn’t fix it. The valve itself had failed.
When we installed the new pilot, a lot of debris came out of the old pilot and the valve body. We flushed it out, bled the air and opened everything back up, but pressure went straight back to 90 psi. The main valve was worn out, and that model is discontinued.
A few weeks later the building called with no water at all. The main valve had stopped passing water, so we opened the bypass to run the whole building through the low-flow line, then installed a new 4-inch flanged PRV with new gaskets.
Try the smallest fix first, then replace what has failed.
Pressure valves are expensive, so we started with the part most likely to fix it.
Measure
Record city pressure and building pressure at the water entry.Adjust and diagnose
Set the low-flow valve, test the main valve and its pilot.Repair
Replace the pilot, flush out debris, and retest.Replace
When the main valve failed, keep water on through the bypass and install a new PRV.Building pressure is back to 64 psi.
With the new valve in, we set the low-flow side to 64 psi and the main side to 62 psi, opening at 60 psi. City pressure is still 110 psi; the building now sees 64. We also tightened the packing on the 4-inch gate valves beside the PRV, which had started to drip.
Building pressure measured at 90 psi against 110 psi city pressure
New pilot valve installed and debris flushed out
Water kept on through the bypass during the failure
New 4-inch PRV installed and set to 62–64 psi
Start with the problem. We will help plan the next step.
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