Anybody with experience with a VSD on a pump motor with a mixing valve??

[zeppy]

have a heating pump motor thats on 24/7 - cant be turned off but on warmer days it makes sense to reduce rpm on pump motor. system has a mixing valve so water flow is necessary all the time.

considering installing a programmable VSD to reduce power use of motor. VSD would be set to reduce rpm over night and also manually reduce it when there is minimal heat demand.

thanks

[duke of earl]

Can you attach a drawing of the piping arrangement?

[AiResearch]

True you really have to look at how its piped.

Is it a manual or automated mixing valve?

Good idea , I think , VFD on pumps , great.

[acwizard]

Need piping diagram or some pictures, how large of a pump are we talking about and what is the minimum flow rate needed.

[just_opinion]

If the sytem has ONLY 3-way mixhing valves, then you cannot reduce the pump's rpm. Because, the further valve will not have enough water.

You may wanna hire a knowledgeable contractor to survey your system and to recommend another way of operation to reduce your power consumption.

Good luck

[cperk]

have a heating pump motor thats on 24/7 - cant be turned off but on warmer days it makes sense to reduce rpm on pump motor. system has a mixing valve so water flow is necessary all the time.

considering installing a programmable VSD to reduce power use of motor. VSD would be set to reduce rpm over night and also manually reduce it when there is minimal heat demand.

thanks

We had one building that had three way valves all throughout, with a VSD. We went in and made blankoffs for the bypasses on all but the end of the piping air handler. We done this to keep hot or chilled water in the system so if an air handler called for chilled or hot water it would have it there already. We are saving alot of tax dollars in electricity to.

[zeppy]

the system has only one mixing valve which is right by the the boiler. the mixing valve is automatically controlled. need to keep water flow to keep a balance between boiler water and water flow to rest of facility

the heating pump motor is 15 HP with 1700 rpm

the goal is to reduce the rpm with a variable drive (or at least allow flexibility) during periods with lower heat demand

has anyone done this?

thanks

[duke of earl]

Still not enough information. Please draw a layout of the system so we can see into the crystal ball. The mixing valve does not tell us enough about the big picture.