Attachment_5_-_Heritage_Center_Field_Report_6-6-2022.pdf

FIELD REPORT

Cushing Terrell Architects Engineers 13 North 23rd Street P.O. Box 1439 Billings, Montana 59103 406.248.7455

Project: Yellowstone Heritage & Research Center – Gardiner, MT Field Report No.: M01

By: Kim Beaudry Project Ref.: XXXXXXXX

Date: 6-6-2022 Time: 8 am – Noon WEATHER: Overcast TEMP RANGE: 36°F to 46°F

Est. % of Completion/Discipline Conformance with Schedule:

Present at Site:

Kim Beaudry – CT, Claude Long, Ron Burke, Chris - National Park Service

Abstract The heat pump loop underground tank appears to be leaking, and the tank is currently being bypassed. The heat pump loop at the Heritage Center is now over-heating and causing cooling issues in the building. The Owner has requested assistance in trouble-shooting the issue. Presently the control system is inaccessible to the Owner.

Field Investigations & Observations

The heat pump loop and heating water system were Investigated with findings listed:

• Checked the heat pump loop system pressure at the inlet of non-operating loop pump. Verified heat pump loop system pressure is at design 22 psig.

• The expansion tank was isolated and inspected to verify the tank is not water-logged and the bladder pre-charge air pressure is correct. Verified the expansion tank is not water-logged, and the air bladder pressure is at design 22 psig.

• Checked the loop connections to the underground tank. The normally closed tank bypass valve is open, the normally open valves to the underground tank are closed.

Cracked the ball valves to the tank and verified the lines are in a vacuum, which is consistent with a tank leak.

• Checked the loop connections to the hot water storage tank. The hot water injection pump P-28 was off, and the hot water inlet and outlet connections to the loop were at loop temperature, indicating no induced flow thru the hot water storage tank.

• Inspected the outdoor cooling tower o The tower fan was operating, and turning in the correct direction.

o The tower discharge damper actuator has failed, and the dampers are currently disconnected and propped open. Later in the day a box with a new damper actuator was discovered on the air handler in the Mechanical Room.

o Opened the tower sump access door and verified the mechanical sump water fill float valve was operating properly and the sump water level was normal.

13 North 23rd Street P.O. Box 1439 Billings, Montana 59103 406.248.7455 o Inspected the tower spray pump, and the pump was not operating. Inspected the pump motor starter and found the pump starter had tripped on thermal overloads.

Pressed the thermal overload manual reset and the spray pump started. Opened a valve on the spray pump discharge piping and verified pump water flow.

NOTE- This verified the pump was operating, however the spray pump discharge header needs to be accessed to verify the spray nozzles are not plugged.

Inspection of the header and spray nozzles inside the tower was beyond the scope of the site visit.

o Opened the tower access door on the side of the tower below the discharge dampers. Visually inspected the tower media on top of the tower. No issues.

Following the Mechanical Room investigation, the team went to the Facilities Office to check the status of the control system access. There was no computer in the Facilities Office. KimB then contacted the Controls Technician (Dave Brenden) that originally installed the controls for the building by phone, and he provided the following information based on his past knowledge of the building:

• The control system is web accessible, and will require the use of a computer with a web browser connected to the building computer network for controls access.

• Although Dave has not worked on the building for quite some time, he does have the controls web access IP address, user name, and password from the last time he worked on the system.

During the investigation, there was discussion with the maintenance staff whether the underground tank is needed, or whether it could be permanently bypassed. See recommendations below.

During the investigation, there was discussion with the maintenance staff regarding winter operation and winterization for the cooling tower. Currently the lines to / from the cooling tower are located underground. The possibility and potential of re-routing the lines to / from the cooling tower overhead was discussed. The Owner indicated they have the in-house capability to re-route the piping. Although the overhead piping would be easier to drain, the existing piping is adequate, is insulated and heat traced, and allows for winterization. See recommendations below.

13 North 23rd Street P.O. Box 1439 Billings, Montana 59103 406.248.7455

Closed Circuit Fluid Cooler-1

Closed Circuit Fluid Cooler-2

13 North 23rd Street P.O. Box 1439 Billings, Montana 59103 406.248.7455

Closed Circuit Fluid Cooler-3

13 North 23rd Street P.O. Box 1439 Billings, Montana 59103 406.248.7455

Findings

Based on the trouble-shooting observations, it appears the cooling tower performance has degraded significantly over time, resulting in a decreased capacity to cool the heat pump loop. The underground storage tank has been masking the problem by cooling the large volume of water in the tank at night, then carrying the building daytime cooling load. Now that the tank has been bypassed due to a leak, the cooling tower capacity issues are becoming apparent. The non-operating spray pump due to the tripped thermal overload also compounded the cooling tower issues.

Recommendations

Cooling Tower Follow manufacturers recommendations and perform service on the cooling tower.

Items requiring service: (including but not limited to)

• Draft fan: fan, motor and belts, electrical equipment

• Spray pump: pump, motor, piping, spray headers & nozzles, electrical equipment

• Tower media

• Tower sump basin

• Tower discharge dampers

• Sump heater

• Chemical treatment system

• Piping heat trace system

Underground Tank As previously discussed, If the cooling tower is operating properly, there should be no need to utilize the underground storage tank. The tank is an energy conservation device that creates a flywheel effect, storing heat in the day and using the heat at night.

Following refurbishment of the cooling tower, the need for the underground storage tank under normal conditions can be tested by isolating and bypassing the storage tank. Should testing confirm the tank is not needed under normal conditions, the tank could then be bypassed and isolated. Should the Owner opt for repairing the tank, testing is recommended to determine if the leak is in the piping or the tank.

13 North 23rd Street P.O. Box 1439 Billings, Montana 59103 406.248.7455

Cooling Tower Winterization During spring and fall “shoulder” seasons, the morning outdoor temps can drop below freezing, and the afternoons temps can warm enough to require heat rejection from the loop. The cooling tower is configured to operate during these shoulder seasons.

All outdoor cooling tower piping is heat traced and insulated with a PVC cover. The spray pump basin has a sump heater to eliminate the need to dump the sump basin every time the outdoor air temp drops below freezing.

During winter months, the tower sump should be winterized. all sump make-up water and chemical feed lines should be isolated and drained to ensure the piping is empty.

The tower spray pump and chemical feed circulation pump and sump heater should be electrically disconnected and locked out, and the pump casings and tower sump basin should be drained. If occasional loop water cooling is necessary after the tower sump is winterized, damper operation & fan control are still available to cool the loop water.

When outdoor air temperatures are below freezing, flow must be maintained in the cooling tower heat pump loop piping at all times to avoid freeze damage. The cooling tower discharge dampers will be closed, and the cooling tower hood and coil sections are insulated, minimizing the heat loss. Draining the heat pump loop piping is NOT recommended. Draining the piping and introducing fresh water and oxygen is very harmful to ferrous (containing iron) piping systems. The combination of iron and oxygen creates iron oxide (rust), so the introduction of oxygen into the piping systems should be minimized.

As an additional safety measure, recommend modifications be made to the controls system to send Facilities Staff critical alarms via email and text message in the event of a loss of heat pump loop flow.

Controls System Contact Dave Brenden with Long Building Technologies (406-797-7082) in Billings, MT to restore controls system access and provide control system service.

End of Report

Attachments

• HP Loop & Heating System Control Schematic

• Expansion Tank Service Diagram