24-BM16 QA.pdf

RFB 24-BM16

CITY HALL BOILER REPLACEMENT

Questions & Answers Questions deadline 7/26/2024

Answers Posted by 8/2/2024 (answers in red)

1. Can we get the gas pressure coming into City Hall? The pipe is 7 inch.

2. Was asbestos found in the boiler? JDR said the current boiler was installed after the required asbestos rules came into effect.

3. Is the City open to alternate boiler brands? The city wants to stick with what JDR has in specs.

4. What are the controls? Niagra system

5. Is there an access route to the exhaust fan? Or plans to the roof? Everything should be in JDR plans.

6. On sheet E200, Keynote 5, it mentions DIF-1 and a receptacle on the roof. Any more information or pictures that can clear that up?

• the location of the nearest receptacle circuit on the roof to be utilized for the GFCI on/near the equipment.

• The location of where the penetration is to be made for DIF-1.

• The location on the roof where DIF-1 is connected.

*See photos on pages 3-4*

7. Is there elevator access or what is the best access to the boiler? Elevator access and stairwell access

8. What is the weight limit for the elevator? 3000 pounds

9. Specifications call to provide points and alarms to the BAS. What is the existing BAS? Niagra system

10. Specification call to match existing control sequence, can you confirm what the sequence is?

Sequence provided below, confirm exact sequence with existing control system.

HOT WATER HEATING SYSTEM

START/STOP

The boiler main loop water temperature shall be controlled by the boiler control panel or boiler controller furnished by the boiler manufacturer. The HVAC Contractor shall be responsible for installing the boiler control panel and providing complete control wiring for the installation.

The boiler control panel shall sequence and stage the boilers (B-1 and B-2) to maintain a constant boiler loop supply water temperature. When sequenced by the boiler control panel, the in-line pump (BP-1 or BP-2) associated with the boiler shall start. When flow is proved by the flow switch on the boiler outlet, the burner shall be enabled and shall fire.

Boiler system shall be enabled by the building automation system through the boiler control panel or controller, with a manual enable provided at the boiler control panel or controller for user control.

The existing main system pumps shall be controlled by the building automation system, existing Sequence to remain.

BOILER LOOP TEMPERATURE CONTROL

Provide for building hot water supply temperature control an outside air temperature sensor and a hot water supply and hot water return water sensor. The boiler control system shall modulate the boiler burner in response to outside air and supply water temperature to maintain supply water temperature setpoint. Building hot water supply temperature shall be reset based on outside air temperature in accordance with the following schedule:

OA HWT

-0- 180 60 140

SAFETIES:

General:

All safeties shall be hard wired to the boiler safety circuits.

Provide alarm signals through Boiler control panel to Building automation system if online boiler fails to maintain primary hot water loop temperature. Upon failure of the online boiler, the second boiler shall fire and operate as required to maintain temperature setpoint.

Boiler Shutdown Switch:

When a Boiler Shutdown Switch is pressed, this shall cause the boilers to be shut down. An auxiliary contact shall be provided to notify the DDC system of a Boiler Emergency shutdown.

Upon reset of the Boiler system, the unit(s) shall restart automatically without user intervention subject to any restart delays.

11. Who is the existing chemical treatment provider? Global Water Technology