§\ THE CITY OF NASHUA “The Gate City’
Division of Public Works
Wastewater Department
DATE: July 22, 2021
TO: Board of Public Works
FROM: David Boucher, Wastewater Superintendent
RE: Variable Frequency Drives, Wet Weather Facility
The Wet Weather Flow Treatment Facility (WWFTF) has four Raw Water Pumps
that move the wastewater and storm water through the WWFTF wet well and
into the rest of the Facility. These four pumps operate based on water level and
controlled by Variable Frequency Drives (VFDs).
One of the VFDs began to fault out so we had all of them looked at by an
outside company. It was determined they were obsolete, couldn’t be repaired,
and all would need replacement. We were proactive in getting quotes, hoping to
get them replaced before failure, however, we saw the first VFD fail completely
on June 30, which prevents us from using that Raw Water Pump. With three Raw
Water Pumps remaining, the WWFTF has no pump redundancy if the facility
receives flows greater than 40 MGD. With three remaining VFDs in similar
condition, the potential to lose them at any moment and an 8-9 week lead time,
we had requested an emergency PO in the amount of $39,980.00 for the purchase
of four VFDs. Shortly after the PO was issued, it was discovered that two of the
vendors had submitted quotes for VFDs that were too small for our pumps. The
initial order was stopped and the PO was cancelled.
<7U dated equipment information was given to all three vendors and new quotes
“ Te wested. We received quotes back from two of the vendors and the
Wastewater Electricians have verified that the proper sized VFDs have been
quoted. Due to the larger size VFDs needed, the quote amount has increased
from the original PO request. We requested an emergency PO in the amount of
$53,605.50 to M&M Electrical of Nashua, NH for the four VFDs needed to keep
‘sctrical of Nashua was the
WA
a,
hone (603) 589-3560 » Fax (603) 589-3474
this critical piece of infrastructure running. M&M
company that provided us the lowest quote.
2 Sawmill Road * Nashua, New Hampshire 03060 +
