RFIs B105 HVAC.pdf
PDF 132 KB Posted
- Attached to
- VGLZ 242015 Repair HVAC B105
- Solicitation number
- W50S8525BA003
About this file
This document is a Requests for Information (RFIs) for Solicitation W50S85-25-B-A003, VGLZ 242015 Repair HVAC B105, dated 23 July 2025. The RFIs contain technical clarifications from the 127th CES regarding a HVAC system replacement project at Selfridge Air National Guard Base. Key details include replacement of six boiler loop pumps, installation of a commercial grade condensing boiler with 920-980 MBH capacity, and replacement of a variable frequency drive (VFD) for the supply fan. The responses address specific technical questions about equipment specifications, piping layouts, mechanical room modifications, and control system integration, with the 127th CES providing precise guidance on sheet revisions, equipment requirements, and contractor responsibilities for the HVAC system upgrade.
The RFIs reveal that the project involves comprehensive HVAC system modifications, including boiler replacement, pump upgrades, and VFD installation. The contractor will be responsible for verifying motor data, reconnecting the new VFD to the existing DDC system, and ensuring all components are installed in an operable and functional condition. No testing and balancing (TAB) is required, and all work is confined to the mechanical room. The responses indicate flexibility in equipment selection while maintaining specific performance requirements, such as the boiler's heat output and electrical specifications.
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Other files
| File | Type | Posted |
|---|---|---|
| OF1419 Abstract of Offers W50S8525BA003.pdf | ||
| Solicitation Amendment W50S8525BA0030001 SF 30.pdf | ||
| Sheet 6 of 8.pdf | ||
| Sheet 3 of 8.pdf | ||
| Sheet 8 of 8.pdf | ||
| SOW Addendum 01.pdf | ||
| Sheet 5 of 8.pdf | ||
| Sign In Sheet 7-16-2025.pdf | ||
| W50S8525BA001 Pre-Bid Conference_Site Visit Slides 7-16-2025.pptx | PPTX presentation |
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Requests for Information (RFIs) as of 23 July 2025
Solicitation: W50S85-25-B-A003, VGLZ 242015 Repair HVAC B105
Q1. Please provide schedules for the new equipment requested. Pump schedule, expansion tank, accessories.
A1. 127th CES: All boiler loop accessories are being demoed and replaced. There are a total of
(6) pumps that will be demoed and replaced. The replacement requirements for all demoed pumps are in the SOW. All of the demoed and replaced accessories are called out in the SOW.
The expansion tank is listed as 100 gallons. The SOW was revised on item 14 to include the addition of flanged stainless steel braided flex connections for all new pumps. tjr
Q2. The boiler schedule indicates to provide a Lochinvar KBN550 or equal, however this model does not provide the 920-980 MBH required by the schedule or indicated in the Statement of work. This would require a much larger boiler, gas supply, and venting. Also, the 550 MBH model is not available, only a 500 or it jumps to a 650. Please advise?
A2. 127th CES: Sheet 5 was revised to say “ Commercial Grade Condensing Boiler” with no reference to a brand name. The 920 to 980 MBH is correct. tjr
Q3. Sheet 8 shows a hot water heating coil, and a finned tube detail, however we do not see a scope of work for any of these devices. Please confirm all work is confined to the mechanical room?
A3. 127th CES: Sheet 8 was revised to be a BLANK sheet with all content removed. All work is in the mechanical room. tjr
Q4. Sheet 6 and 8 show 2 different piping layouts. Which one should we follow for piping, layout, pipe sizing, and components of the system?
A4. 127th CES: Sheet 8 is a schematic of the original system. Sheet 8 was revised to be a BLANK sheet with all content removed. Sheet 6 was revised and is a schematic. Per the SOW piping changes to the boiler primary and secondary are required by this contractor to provide the required lead lag configuration. tjr
Q5. Does the existing combustion air louvre within the mechanical room need to be sealed off after the new pipes are routed through the roof?
A5. 127th CES: No changes required for mechanical room louver. Tjr
Q6. Please provide more detail on the requested VFD’s for the air handling units?
a. What is the motor data the vfd is supplying? HP, voltage, current, any other specific requirements, etc. . 127th CES: The SOW Option 01 – states that the supply fan is 20
hp. This Fan is 460 V – 3 phase. This contractor will verify all of this data prior to ordering as is standard process. tjr
b. The statement of work indicates multiple units; however the drawings only appear to show 1 unit. 127th CES: The SOW Option 01 - requires that the VFD for the supply fan be replaced. tjr
c. Is air balancing, or TAB required after installation of the new VFD’s? 127th CES: TAB is not called out in the SOW and is not req’d. tjr
d. Do any programming or control changes need to be done to the VFD? Is the unit only utilizing S/S, speed, status, and alarm hard wired points? 127th CES: DDC will be modified as required per the SOW by this contractor to reconnect the new VFD to the DDC in an operable and functional condition. There currently is an existing VFD working in this location on the supply fan and some minor changes and additions may be required for the new VFD. tjr
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