McQuay/Mark4 board question

[moonie]

Hello, We will be working on some McQuay/Snyder general water source heat pumps Model # cch042amts with the Mark 4 board in them. The cust. would like the 2 way valve to shut off water flow when unit has no call for cooling or heat. The water lines also have flow switches on them that will need to shut off unit in the case of no water flow. Just looked at the job late friday so I was hoping to get a little input/ideas for when I revisit this ,The mark 4 boards look to have a D.C. power and A.C. power. The units that I have seen so far have no lit. with them. The way we were going to do it was by adding relays (1 cooling/1 heating/1 flow) but any input is appriciated. Im not to familiar with the Mark 4 board and Im hoping someone knows of an easier way to accomplish this. Cust wants this done done for energy savings. Thanks in advance for any help

[TitleLess]

What are they targeting for energy savings ? Pump head ?

[moonie]

Yes title savings on the pump...sorry forgot to put that

[TitleLess]

Most places I have seen do not have them installed, how many are you talking about ?

[moonie]

A total of 15 units

[TitleLess]

Is there an energy management system present ?

Is there a drive on the pump ?

[moonie]

Supposed drive on the pump,but have not seen it yet...ems system being installed

[TitleLess]

15 is a small number, I would try to have them concentrate there efforts to save energy in a different direction, investing their resources into an EMS system to handle these units is going to bring them a far greater return than putting those valves in.

As far as a flow switch goes, there are several places you can tie it into on the board or the unit,depending on what you want it to do when it has no flow,

The AC and DC outputs should be of little concern, you just have to pick one to use, I would just use the AC, its just the switching voltage that you must run through a set of dry contacts, eg; thermostat, controller, etc. then back to the inputs on the board.

There is a pump request signal on these boards, but I am assuming that you won't need that if you have no EMS, it is a DC signal, and is basically on or off

0VDC = off / 30 VDC = on

[moonie]

Thanks for the input title...do you know what those terminal are identified as on board???

[TitleLess]

Originally posted by moonie
Thanks for the input title...do you know what those terminal are identified as on board???


Which ones ?


http://www.mcquay.com/mcquaybiz/literature/lit_at_wshp/IMOM/OM_120-3.pdf

[moonie]

Thanks title for the info you sent...I think it will be a great help

[TitleLess]

You can get a lot of lit from their public site,

http://www.mcquay.com

[sabre11134]

On the mark iv boards, you can put a motorized valve on with a end switch on the valve. If i recall taco makes a valve which will allow the compressor not to start until the valve opens. you have a hot lead , a common, and the third lead will send the signal when the valve is open. has been about 10 years since working on this style unit.Not certain their may be some terminals to feed a/c voltage to this board.

[thermo]

McQuay has an optional Erie motorized valve option for heat pumps with Mark IV controls. The applications used are for either positive water shutoff when the unit is in the unoccupied mode (tenant metering of off use water) or when variable speed drives are applied on the water loop.
Not too exotic and were generally factory supplied and supported in the Installation manuals.