HVAC Circulation Pump Control

sounds like a job for a lead/lag switch.

Either that, or an operating procedure, advising a human being how and when to swap the pumps over, perhaps.

Or call an instrumentation engineer.

Whatever you do DO NOT CALL Siemens and ask them for help! They just built the controller and wrote the software.

Usually free advice is worth what you pay for it.

Spend a buck and get it right.

Are the pumps isolated by automatic check valves or are there valves that need to be changed when you alternate the pumps? That could change the answer significantly. Woody

Dear All,

The problem is like this:

In our boiler room there are two pumps (main - spare).

When the control valves reach their set point, valves get closed, but pumps continue on circulation, and the pressure on the line increases.

I want to control flow rate according to outgoing and incoming pressure information on the line by using one sensor which is capable of reading both these values (differential pressure sensor).

Siemens Wilo VSD panels are simple for this application. But I want to use my pumps as co-aging. And Wilo does not have this function.

I want to built my own panel with two VFC (variable frequency controller), one time switch to changeover pumps, Siemens RLU222 controller (Basic Type u2 program preinstalled), one anolog signal cuopler (RLU222 gives analog signal speed reference for pump, but when a change over the pump second pump should work with the same speed). When pressure is increasing on the line, the working pump should slow down.

But I do not know the software to check and set parameters of RLU222. I have ACS800 but it is only used for setting the parameters of RMU controllers.

Also I am waiting for your comments about this problem and my solution method?

leiurucus

electrical electronics engineer

Hire someone with the knowledge to perform the task at hand.

Not everything in life is free.

Good luck.

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Since the controllers are independent and ignorant of each other, the only thing you have to do is to fool one into believing to be hotter than the other. No discussion with Siemens, no modification, purely external.

ADD a degree of temperature to one sensor on your odd birthday, then switch the gizmo over the other on your even birthday. Every year, good repair from OM, overall happy people, including me. K.I.S.S. Bye. Duh.

Happy new year!

Throw the Siemens unit away and fit a pump changeover module IO_PMPCO from www.syxthsense.com

OK reading what you are describing calls for many changes.

1. The Controller you purchased has the DI/DO and AI/AO capability to handle this simple task you ask of it.

2. You have installed VFD's, but when the valves close the pressure rises? The purpose of the VFD's is to control loop flow and slow the pumps down when there is no flow demand (valves closing).

Here is the fix.......You will not be able to program this yourself send it to Siemens, it is a proprietary controller that will need their programming tools.

You need to develop a specific (or hire and engineer) Sequence of Operation for your site. Once that is done you can send the sequence to a Siemens programmer that will enter the code into the controller and they will also supply you with the loop devices. They will probably have a dump program or jar file they will dump into the controller for you at a cost....what you are asking to do is very simple and everyday type of BMS work.

Spend the money have it done right, hey I could sell you a new device to do the job but it will still need to be programmed with the manufactures tools. The controller you have is fine................SPEND THE MONEY!!!!