Primary Secondary Pumping
Primary Secondary Pumping
(OP)
Hi, I'm designing heating for a 12 story residential building with PTAC units @ 400 GPM & 180F. The developer does not want to use primary-secondary pumping. I know the benefits in control and design by using primary-secondary, but is it absolutely required. Will not using it a cause problems in a system of this size.
Thank you.
Thank you.





RE: Primary Secondary Pumping
RE: Primary Secondary Pumping
RE: Primary Secondary Pumping
Your developer has typical logic for your project. Primary boiler pumps are typically single phase and around 10' head. They, along with VFD's are relatively inexpensive.
I gather that the developer has a fixed fee for heat charged to the tenants, included in the rent ..... Right?
RE: Primary Secondary Pumping
I have designed primary systems with two-way valves and flow control devices without adverse affects on the boilers used. Boiler selection would be critical in this case.
The pressure on the boiler may be an issue depending on where the boiler room is situated. If it is a penthouse boiler room there won't be a problem, if it is at a lower level you may have issues depending on the boiler type eg. Viessman doesn't like to exceed 28 psig through the boiler. You would then have to isolate the boiler via a heat exchanger.