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[jhall423]

I have a water cooled heat pump and would like to use the thermostat (24v output) to start my cooling pump through an X10 module.  Can someone help me with what I will need?

[dave w]

I have a water cooled heat pump and would like to use the thermostat (24v output) to start my cooling pump through an X10 module.  Can someone help me with what I will need?

Don't know how broad you intend this question to be. As far as direct control of the heat pump, a
Universal Module can be used to make and break the thermostat's common line.
http://www.x10.com/automation/um506_s.html

[Charles Sullivan]

I have a water cooled heat pump and would like to use the thermostat (24v output) to start my cooling pump through an X10 module.  Can someone help me with what I will need?

Don't know how broad you intend this question to be. As far as direct control of the heat pump, a
Universal Module can be used to make and break the thermostat's common line.
http://www.x10.com/automation/um506_s.html

I think perhaps what the OP has in mind could be accomplished with a PF284 Powerflash Module.  This would be actuated by his thermostat and send an X10 signal to an Appliance Module controlling the cooling pump.   Since pumps can generate noise on the AC power line, an X10 Noise Filter between pump and Appliance Module may be required.    (The particular models of Appliance Module and Noise Filter to use depend on the electrical rating of the cooling pump.)

But a question that needs to be asked is what would happen if (for one reason or another) the X10 signal failed to turn On or turn Off the cooling pump as called for by the thermostat?   Would this damage the heat pump or other systems in the house, or create a hazardous situation?

[dave w]

Yup, I mis read the OP original objective. PowerFlash is the answer.


jhall423,
Is the water cooling to actually cool the heat pump OR to mist the condensing coil to increase efficiency?

[jhall423]

It actually cools the heat pump.  The only thing that will happen if the pump does not start is the compressor will go out on over pressure or temperature.  Either way it's double protected for this reason.

[jhall423]

Will the power flash work on 24v ac or will I have to add a relay?  Thanks for your help.

[Brian H]

http://www.x10.com/security/x10_pf284.htm
The users manual didn't show up in a search of X10.
The X10Pro PSC01 is the same from X10Pro.
Manual attached.

It indicates it can be triggered by up to 18 volts AC or DC. Maybe a dropping resistor could be added to extend the voltage to 24 volts.

[Charles Sullivan]

http://www.x10.com/security/x10_pf284.htm
The users manual didn't show up in a search of X10.
The X10Pro PSC01 is the same from X10Pro.
Manual attached.

It indicates it can be triggered by up to 18 volts AC or DC. Maybe a dropping resistor could be added to extend the voltage to 24 volts.

The input impedance of a Powerflash is pretty high, around 1 megohm as I recall.  A voltage divider would probably be more certain - I'd probably use a pair of 100 Kilohm, 1/8 or 1/4 Watt resistors, which would drop the thermostat voltage to 12 Volts.

[Boiler]

It actually cools the heat pump.  The only thing that will happen if the pump does not start is the compressor will go out on over pressure or temperature.  Either way it's double protected for this reason.

jhall,

I'm sorry, but this is not something that I would use X10 for (or any automation technology for that matter).

The over pressure/temperature systems are designed for protect the system from catastrophic failure in the event that the cooling pump/switching system fails.  The pump and switching system have a predictable reliability and I would assume that the backup system has taken that into account.

By adding X10 to the mix, you are increasing the likelihood of a pump malfunction.  The pumping system has been designed to provide years of service.  With a good X10 system, you might expect 99% performance.  Run the numbers and see how many missed actuations that comes up to over a one year time frame. If you are lucky, this added stress cycling will simply wear out the compressor system earlier than it was designed for.  If you are unlucky, you will wear out the protection devices and suffer catastrophic failure.

Using my favorite auto analogy, manufacturers put emergency breaks on cars in the event of a primary braking system failure.  Anyone that has had to use them can attest to the fact that they are a last resort.  Using the system repeatedly will quickly wear out the backup and result in catastrophic failure (Bill Gates calls this a crash).

 

[dave w]

It actually cools the heat pump.  The only thing that will happen if the pump does not start is the compressor will go out on over pressure or temperature.  Either way it's double protected for this reason.

You can do it with X10, but X10 signalling over the powerline is very vulnerable to noise knocking out the signal. A compressor start is very noisy which will be occuring at the same time that the power flash would be signalling the change in state at the thermostat.  It would cost you less than $50 to try X10, but with something as critical as keeping the compressor cool I would direct wire it. If the cooling pump is 120V what about just wiring a 220V coil relay across the compressor and use the relay to run the pump?

[Msradell]

Just use a 24 volt relay.  Much simpler and less prone to failure for this application. 

[U4ia2000]

I am interested in water cooled heat pumps-- may I ask where you got yours?