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Post by stuartii on Sept 19, 2012 10:03:36 GMT -5
Hi all ,
Thanks in advance, I am looking for some advice, i have recently been talkng to cye and he advised me post here when looking for some more advice.
My system has been oversized this given me a problem on stagnation during the summer months 30 tubes 144 litre tank south facing , i need a quick and easy heat dump just to get rid of excess water into a barrel were i can use it in the garden and not too waste it..
so cye advised me to purchase a SIEMENS CYLINDER OR PIPE THERMOSTAT and a N/C 24V DC 1/2" 250mA Electric Solenoid Valve.
just need to know how i go about setting this up wiring etc..
Many thanks
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Post by cye on Sept 20, 2012 2:39:27 GMT -5
hi
power requirement for valve: first check the valve with 12v. if you can blow through it with it connected to a car battery, then it will work with a 12v power supply, otherwise there are numerous inexpensive 24v PSUs available on eBay. is there a power or current rating on the valve (say in either W or ma)?
height requirement for valve (below cold water tank): is there a minimum pressure stated on the valve (in either metres, bar, mbar, mpa. if it's in mpa then 1 mpa is equiv to 10bar.
thermostat wiring : there will be a wiring schematic on the stat - can you scan or photograph it and post it up?
thanks
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Post by staurt on Sept 20, 2012 8:58:06 GMT -5
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Post by cye on Sept 20, 2012 15:09:33 GMT -5
here's the thermostat spec that stuart emailed me Attachments:
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Post by cye on Sept 21, 2012 2:39:42 GMT -5
Stuart
How to wire the thermostat. We'll assume you are powering your solenoid valve from a 12v car battery. you will hvae one positive (red) wire and one negative (black) wire travelling from the battery terminals to the solenoid. make a break in the red cable and connect one side of the break to terminal 1 of the thermostat and the other side of the break to terminal 3. in this way the stat operates as a 'normally open' switch, not allowing power to the solenoid until the preset temp is reach, at which point the stat connects terminals 1 & 3.
assuming your tank is surrounded in solid foam, remove the foam from a small area of the tank, at a height slightly above where the lower soil coil connection enters, but not near the connection, rather at the far side of the tank or a least a foot away from it. in this way your stat will measure the temp at a fairly low point in the tank. try and get a good tight fit between the stat and the bare copper of your tank. if it's not a tight fit perhaps use tin foil or a copper pot scrubber to aid heat tansfer to the stat.
hope this helps.
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Post by cye on Sept 22, 2012 1:38:40 GMT -5
here's a pic of the heat dump pipe exiting the wall. as it is not feeding directly into a drain, to avoid the risk of scalding, i have curved the pipe over so that the scalding water flows safely down the side of the wall. i have also used 10mm pipe so i could drill easily through the mortar rather than have to damage the brick. easier to bend too. as the stat method may be slightly slower to react than a digital temperature controller, 10mm is also a good idea as the flow rate of the heat dump is limited somewhat. hope this helps Attachments:
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Post by cye on Sept 22, 2012 1:43:43 GMT -5
wiring for solenoid. open up the white plastic cover and there should be two terminals there.
2 core lighting cable from your local electrical supply shop should suffice.
please let us know how you get along.
regards
cye
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Post by Stuart on Sept 22, 2012 2:27:19 GMT -5
thanks cye, quick question i am going to place my solenoid valve under the kitchen sink, my thermostat need to be next to the tank upstairs i guess, so i guess i need to run a cable between the solenoid and the thermostat. 1, still having trouble finding a psu for solinoid can you help? need wires also .. not very good at this 2, will send picture of my tank for help were the best place to position thermostat 3, how do you make a break in wire ? what type of connection connection sorry for all the questions mate
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Post by Stuart on Sept 22, 2012 2:37:00 GMT -5
sorry you all ready told me with regards to the wire for the solenoid is 2 core lighting cable would that go to the psu...
i have sent pics with regards to the thermostat potion
cheers mate
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Post by cye on Sept 22, 2012 9:18:51 GMT -5
here's one way of doing the wiring, and keeps all the DIY cabling low voltage & safe. the break in the negative wire is rejoined using a 'con block', available for a few pence from your electrical supplier. (there is another technically better method not shown here, whereby the stat is used to switch the 240v power to the psu. This would prevent the psu from being on all the time, but i have not shown it here on the basis that your may be uncomfortable with mains wiring.) if you are concerned with having the psu powered all the time you could mitigate this by putting the psu on a timer. hope this helps Attachments:
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Post by cye on Sept 22, 2012 9:33:35 GMT -5
this transformer on ebay looks like it's exactly what you need, though you should check with the vendor to confirm that the output is DC
200822247620
or this one here, but it's more powerful than you need (but still ok) 170782122860
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Post by cye on Sept 22, 2012 9:40:09 GMT -5
here's a pic of stuart's tank. that thing in the middle, on right hand side, with the strap around the tank holding it in place,, is a thermostat already fitted and presumably for the central heating. the heat dump stat should be fitted in a similar manner, albeit lower in the tank, but following the method used for the other stat, i.e., cut into the insulation, expose the tank surface, insert the stat, fit the tie/strap around the tank to hold in place. Attachments:
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Post by cye on Sept 22, 2012 9:42:13 GMT -5
here's another pic of stuart's tank, this time the lower section of the tank. the two connections visible on the left hand side are the solar coil connections. the stat should be fitted to the tank at a height an inch or so above the lower solar connection, but at least a foot away from the solar connection, perhaps below the other stat. Attachments:
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Post by stuarti on Sept 22, 2012 11:32:16 GMT -5
Thanks cye excellent , quick question about the psu 200822247620 on the picture how do i connect a cable to the one shown the positive and minus, i know this might sound daft. thanks very much mate, also i was thinking instead of running the water to the out side i might fit it to the drain under the sink can you see a problem... thanks cye
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Post by cye on Sept 22, 2012 15:38:21 GMT -5
it looks like a DC jack, probably centre pin + but it will state the pin polarity on the label. make sure to check with the vendor that the output is DC
no problems feeding heat dump water into a drain.
let us know how you get along
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