Simple Cheap High Voltage High Current Control

When I designed my system, I tried to use the Centralite system for all my high voltage automation controls. I did my best, but I missed things.

We have a hot water circulating system that provides near instant hot water by constantly moving it through the hot water tank. It's a giant waste of energy to operate it when its not required. It has an analog timer built-in, but it's not flexible.

I put a Crydom SSR in a double j box, wired the hot side from an AC cord to a duplex outlet I installed in the box and routed the low voltage wires outside to a terminal strip. The SSR is rated for 40 amps @ 250v and only requires 10ma @ 12v to trigger. I use an M1 output to control it. Now it shuts off whenever the system is armed away and during the night.

Cost was about $15.

Brian

I did this also, but used an X-10 appliance module to control the pump. I have keypads and such so anyone can turn the pump on and (via my Ocelot) it will turn off in five minutes. This way one only has to press a button a few minutes before they want to shower (say press the button before undressing) to get instance hot water.

You have your pump run full time during the day?

These sure look prettier than my HVAC contactors and appear cheaper

BraveSirRobbin said:

I did this also, but used an X-10 appliance module to control the pump. I have keypads and such so anyone can turn the pump on and (via my Ocelot) it will turn off in five minutes. This way one only has to press a button a few minutes before they want to shower (say press the button before undressing) to get instance hot water.

You have your pump run full time during the day?

Click to expand...

Only if someone is home, otherwise the M1 turns it off.

Maybe we should keep a usage chart for a week and come up with some patterns for more "off" times.

I considered pulsing the unit on and off at intervals of perhaps 15 minutes when in use, but I'm not sure that wouldn't take a toll on the pump.

Now after thinking about it, other than wake and sleep, and perhaps, meal times, it probably doesn't get used much. You've got me thinking.

Brian

brotsten said:

When I designed my system, I tried to use the Centralite system for all my high voltage automation controls. I did my best, but I missed things.

We have a hot water circulating system that provides near instant hot water by constantly moving it through the hot water tank. It's a giant waste of energy to operate it when its not required. It has an analog timer built-in, but it's not flexible.

I put a Crydom SSR in a double j box, wired the hot side from an AC cord to a duplex outlet I installed in the box and routed the low voltage wires outside to a terminal strip. The SSR is rated for 40 amps @ 250v and only requires 10ma @ 12v to trigger. I use an M1 output to control it. Now it shuts off whenever the system is armed away and during the night.

Cost was about $15.

Brian

Click to expand...

Can this be hooked up directly to one of the outputs (like output 10) or does it need an intermediate replay and transformer?

I looked at my water circulation pump also. I did the math and figured it was only costing me $3 a month to run it full time. I will eventually hook it up to the M1 and turn it off at night at least but the savings moved it down on the priority list. Looks like you did a nice job with it!

brotsten said:

BraveSirRobbin said:

I did this also, but used an X-10 appliance module to control the pump. I have keypads and such so anyone can turn the pump on and (via my Ocelot) it will turn off in five minutes. This way one only has to press a button a few minutes before they want to shower (say press the button before undressing) to get instance hot water.

You have your pump run full time during the day?

Click to expand...

Only if someone is home, otherwise the M1 turns it off.

Maybe we should keep a usage chart for a week and come up with some patterns for more "off" times.

I considered pulsing the unit on and off at intervals of perhaps 15 minutes when in use, but I'm not sure that wouldn't take a toll on the pump.

Now after thinking about it, other than wake and sleep, and perhaps, meal times, it probably doesn't get used much. You've got me thinking.

Brian

Click to expand...

Most electric pumps are rated by on cycles. The more you cycle it the shorter the life, typically. Check the spec sheet if you can find one.

Where did you find that relay for $15?

ctay said:

I looked at my water circulation pump also. I did the math and figured it was only costing me $3 a month to run it full time.

Click to expand...

I wouldn't mind seeing details of those calculations. Maybe my methodology of switching during actual use is wrong.

Dan, here's one source...

http://www.mpja.com/products.asp?dept=133

AnotherOne said:

Can this be hooked up directly to one of the outputs (like output 10) or does it need an intermediate replay and transformer?

Click to expand...

These only draw 10ma, so you can hook them directly to an unused output. I guess you connect 5 to one output as the M1 is rated for 50ma per output.

Brian

Dan (electron) said:

Where did you find that relay for $15?

Click to expand...

I bought 10 on eBay for $80.

Brian

it may be cost prohibitive but what about some type of flow detector which sets a virtual output in the elk on for 1 hr reset if running... and this will turn the pump off if the hot water hasnt run for 1 hr or what ever you set the time period for.... agian if it only cost pennies per day to run 24/7 then why not run it when ever the elk is not armed away....

ctay said:

I looked at my water circulation pump also. I did the math and figured it was only costing me $3 a month to run it full time. I will eventually hook it up to the M1 and turn it off at night at least but the savings moved it down on the priority list. Looks like you did a nice job with it!

Click to expand...

Is that $3 for the electricity for the pump plus whatever energy the water heater consumes to make up for the heat loss in the recirc system?

I think my savings is signifcantly more than $3 by only running my recirc pump 5 hours per day. All the pipes are insulated, but the recirc loop is over 200 feet.

Good point and I should have clarified my request for additional information for this cost calculation. I'm not too concerned about calculating the cost to operate the pump itself (I can just put my Kill-O-Watt meter on it and see how many watts it is using for this simple calculation). I was more concerned about running hot water continuously (pump just left on) as now the hot water is circulating over many, many feet of non-insulated pipe. This would not be an easy calculation as one would have to do a thermal model of the pipe (thermal resistance), then de-rate the hot water tank’s performance based on this value (i.e. beyond me :blink.

I’m not a thermodynamic expert, but I’m thinking the cost of having to re-heat the water that is outside the tank (running through the pipes) is more than the cost of running the pump itself. This is the main reason I only run the pump on demand as described above.

Perhaps someone more familiar with these models can give further guidance (as I also stated above, my thinking on this may be wrong)!