Domestic hot water problem:

Dan Gigante

I am looking for a schematic of a downfeed domestic hot water system for a 23 story apartment building in nyc.The system has a water tower downfeed to the dhw coils.Than from the outlet of the 3" holby mixing valve an express riser to the ceilng of the top floor,than all risers feed down to apartments.The bottom of the risers are connected without check valves into a manifold which increases in size as it picks up all risers than terminates into a "1/4 HP" domestic hot water return circulator in the boiler room.some tenants complain they have to wait 20 min for hot water.Thanks for any suggestions .Dan G

[Deleted User]

Can you..

make up a quick schematic? I'm not sure what you have in your minds eye is what I'm seeing.

ME

Alan(CaliforniaRadiant)Forbes

Did it

ever work? If so, that means something has changed (i.e. circulator not working, air in the lines, etc.).

It would be nice to have ball valves on the branches before they tie back into the header at the bottom; that way, you can adjust flow to make up for pressure drop.

Make sure the pump is large enough to push the water through all that piping.

And make sure the check valve (which should be after the pump and before it ties back in to the system) is closing properly, although if the pump is always on, it will never close. We had problems when copper reamings prevented the check valve from closing when the pump was off; cold water would back up the recirc. line and create havoc: showers would turn tepid.

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

[Deleted User]

Are the complaining

tenants on the top floors, close to the mechanical room, or spread throughout the building?

Dan Gigante

domestic hot water problem

Thanks for your advice,the ballvalves were installed. I used them to balance the system .Its working very good now.




sincerly,Dan Gigante