SAN DIEGO — Right there across from the San Diego Padres new Petco Park, with views of the historic Gaslamp Quarter and San Diego bay, stood a really ugly hotel. You know it was an ugly hotel when its owner thinks it was an eyesore.

"It's a tilt-up concrete structure that was the sore thumb of the San Diego skyline," said Robin Callaway, vice president/commercial operations for mechanical contractor A.O. Reed.

Last October, the 15-year-old hotel was shut down and its owner, the San Francisco-based Stanford Hotels, announced plans for an extensive makeover inside and out.

"The building has basically been stripped to the bare bones and now we're putting it back together," said the hotel's General Manager Jim Durbin, noting nary a window frame, electrical wire or bathroom pipe remains from the original property.

It's the hotel's prime location that persuaded the owner to abandon an earlier plan to spend $12 million for guest room renovations alone. Instead, it is pumping close to $40 million into a complete overhaul, including new heating, air conditioning, plumbing and electrical as well as upgrades to fire-life safety systems.

Describing it as akin to the "Phoenix rising from the ashes," Durbin said when the hotel reconstruction is complete later this year, "It will be a gorgeous new property."

From a mechanical perspective, it needed a gut rehab, Callaway said.

The building contained a Sovent DWV system that had been eaten away by caustics, Callaway said. The drainage system had also been pummeled by water softener salt, heavy detergents from the laundry and swimming pool overflow. The HVAC piping was shot. Callaway speculates that it may have been from neglected water treatment. In addition, it was Type M copper that showed high-velocity erosion. A.O. Reed is replacing it with Type L.

The 21-story building is a rectangle up to the ninth floor. After that it rises as a U-shape. The configuration gives it two roofs to use for mechanical equipment. The kitchen exhaust, for example, terminates on the lower roof.

Guest rooms are in the U. The first floor contains the lobby and the hotel's restaurant, followed by five floors of semi-enclosed parking garage, topped by an eighth floor containing meeting rooms, administration and the grand ballroom. The top floor of the hotel features a penthouse health club and an outdoor bar.

Callaway noted that Stueven Engineering, Escondido, Calif., designed the mechanical systems with a designassist from A.O. Reed.

Coming in from the city water service, A.O. Reed installed three Armstrong booster pumps that feed water through a 4-in. main up to the rooftop. The rooftop mechanical room contains two Raypak boilers and a 1,000-gal. storage tank. Water in the fully circulating system heads downward through a 3-in. primary riser with separate risers for the back-to-back guestroom bathrooms. Manifolds on the ninth floor recapture the water, which is pumped back up to the roof through 3/4-in. lines. The circulating domestic water loop is set at 120F.

The kitchen and the laundry each have their own Raypak boilers and separate hot water systems.

That plumbing serves guest bathrooms with Crane toilets, and Kohler and American Standard tubs and sinks. Faucets are by Dornbracht. Public restrooms all used Sloan flushometers.

The Crane toilets are floor-mounted rear-discharge units that match up with the holes used for the Sovent system. Callaway thinks that floormounted, rear-discharge toilets are always a bad idea — let alone for a seismic area — because the floors and walls of any structure anywhere will shift in different directions over time. A.O. Reed had no choice, however, because engineers said that boring 3-in. holes in the floors for bottom discharge toilets would degrade the structure.

The HVAC system is primarily fourpipe hot and chilled water through Carrier vertical fan coil units, supplied by a 215-ton McQuay air-cooled R-22 reciprocating chiller. Each room is individually controlled with a Honeywell thermostat.

The chiller also supplies large Mc-Quay air handlers for the corridors, meeting rooms, ballroom and other common areas. Some air handlers are on the upper roof and some on the lower roof. One on the upper roof supplies 100% outside air and controls the humidification levels of the corridors. Air handlers feed VAV systems in the common areas.

A.O. Reed used all Greenheck fans for pressurization and exhaust.

The central corridors for guest rooms are pressurized at one end with air supplied by the humidification/ dehumidification unit and power exhausted at the other end. Constant volume fans pressurize the elevator shafts. The stairwells are static pressure controlled via variable frequency drives. Both stairwells and elevator shafts have a higher pressure than the corridors, and the corridors are at a higher pressure than the guest rooms.

Each guestroom bathroom has a light switch interface to an exhaust fan that leads into a shaft with a constant volume exhaust fan on the roof. Because there's a 22-in elbow between the guest rooms and the central shaft, they couldn't use fire dampers, so the guestroom fans will run even during an emergency shutdown so smoke can't be forced from one guestroom to another.