Cylinder Thermostat

I've just fitted a new Cylinder Thermostat same as this :

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been wired up same as previous stat : 1= Yellow 2= White 3= Blue & Earth

I sparked up the system and left it running for half an hour (usually long enough for reasonably hot tank of water) I then turned down the temp. control to see at what point it shut off, It didn't !! I turned it down to lowest setting 20 deg.C still no joy.

Is it a faulty stat ? or incorrectly wired ?

Cheers

Reply to
KnobJockey
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> Its been wired up same as previous stat : 1= Yellow 2= White 3= Blue & > Earth

I'm mystified why you have connected the earth to pin 3. The 'further information' link on the page you quoted shows the unit has a separate earth terminal.

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1 and 3 make a connection as the temperature rises, while pins 1 and 2 break on temperature rise. Normally I'd expect to see connections to pins 1 and 2 which will make a circuit to fire the boiler when the temperature is low and will break the circuit when the desired temperature is reached. I'd expect earth to be connected to the earth terminal - not pin 3.

Was the previous stat an identical unit? If not, what leads you to believe that the connections on the previous one are the same?

I'd check whether or not the connections are really the same on both units (if necessary use a meter) and check what happens at the other end of the cable.

Mike

Reply to
mheden

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Without knowing what wires go where at the other end of the circuit (i.e. at the controller/wiring box end), it's impossible to comment with any authority, although my immediate reaction would be to suspect that it was incorrectly wired - for a start '3=blue and earth', which is nonsensical taking a quick look at the installation instruction leaflet that is linked from the page you listed. You did take a look at that link, didn't you?

If you've connected an earth wire into what could be potentially a live circuit, never mind about how it was wired before, then you don't understand what you're doing and should consult an electrician.

Reply to
The Wanderer

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>>> Its been wired up same as previous stat : 1= Yellow 2= White 3= Blue & >> Earth

Re-read the post. I maybe wrong but I took it that the OP meant to say 3 =blue plus there is also an earth connection.

I would guess that if all 3 terminals are being used on a cylinder stat then it is probably a Y plan and the fault may lie in the midposition valve not the stat.

Adam

Reply to
ARWadsworth

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> Its been wired up same as previous stat : 1= Yellow 2= White 3= Blue & > Earth

Who knows? Without more information about what type of system configuration you have (S-Plan, Y-Plan, C-Plan, etc.) and what is at the other end of the yellow, white and blue wires, it's impossible to say.

Reply to
Roger Mills

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>>>>> Its been wired up same as previous stat : 1= Yellow 2= White 3= Blue & >>> Earth

A missing comma adds greater validity to my understanding.

Have I said what I mean? Did I mean what I said?

Reply to
The Wanderer

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Its been wired up same as previous stat : 1= Yellow 2= White 3= Blue & > Earth

Why did you replace the original? If it was because of the same 'fault', it isn't the thermostat. More likely a valve.

Reply to
Dave Plowman (News)

To clarify matters, the earth is fitted correctly to its own connection (not attached to any other). I have replaced a sunvic stat (which works ok) with the danfoss because the danfoss has more of a lower temp. range.

Also with the new danfoss there is no audible click when the control knob is turned (either when hot or cold)

Reply to
KnobJockey

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