Pipe stat not turning pump on (3)

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Hi I’ve a pipe stat connected to a danfoss wc4b control centre which then should fire a pump for my back boiler, stat is getting power from the controller but doesn’t seem to be sending a live to the pump. Any ideas I’ve attached photo of danfoss controller setup black cable on bottom of number 1 is the live to the stat and the pump and the stat brown lives are into number 3. Any help be very much appreciated
 
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Duplicates merged
Hi I’ve a pipe stat connected to a danfoss wc4b control centre which then should fire a pump for my back boiler, stat is getting power from the controller but doesn’t seem to be sending a live to the pump. Any ideas I’ve attached photo of danfoss controller setup black cable on bottom of number 1 is the live to the stat and the pump and the stat brown lives are into number 3. Any help be very much appreciated

Read more: https://www.diynot.com/diy/threads/pipe-stat-not-turning-pump-on.582359/#ixzz7Dv1knXjz
 
Picture of said stat showing how its wired would be
Hi apologies I’m not at home and know a pic on inside stat would be helpful as far as I can remember the black wire is on the left
Hand side and brown is far right I’ve a pic of outside of stat but will post inside as soon as I can tomorrow am
 
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Here’s the stt
 

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Chase the fault.

Is the pipe sending heat to the stat? Daft question, but still, if its empty because it leaked, it won't do....
Is the stat switch ticking when you turn the dial? If not, its goosed. Buy a new one.
Is the stat getting power? Check with a multi meter.
Is the stat closing the circuit when on? Check with multimeter.
If the stat is all good, move onto the next thing in the chain (the pump).
Is the pump getting power when the stat is energised? No, thats the fault.
If it is, should the pump be spinning. If not, perhaps the pump needs attention.
Perhaps its a simple fuse or trip somewhere.

Set out the logic in the system and check each part.
 
Chase the fault.

Is the pipe sending heat to the stat? Daft question, but still, if its empty because it leaked, it won't do....
Is the stat switch ticking when you turn the dial? If not, its goosed. Buy a new one.
Is the stat getting power? Check with a multi meter.
Is the stat closing the circuit when on? Check with multimeter.
If the stat is all good, move onto the next thing in the chain (the pump).
Is the pump getting power when the stat is energised? No, thats the fault.
If it is, should the pump be spinning. If not, perhaps the pump needs attention.
Perhaps its a simple fuse or trip somewhere.

Set out the logic in the system and check each part.

Hi there is power to the stat, the stat is attached on the stove return pipe which gets hot, the stat will click in and out at correct temps, the pump doesn’t get any power at all, it’s working as when connected to central heating pump power it powers up, but the stat doesn’t seem to be firing the live to the pump when it should be. The black wire in the stat is the one with mains and the brown goes back to the danfoss controller into the bottom of number 3which the live for the pump is also connected
 
Hi there is power to the stat, the stat is attached on the stove return pipe which gets hot, the stat will click in and out at correct temps, the pump doesn’t get any power at all, it’s working as when connected to central heating pump power it powers up, but the stat doesn’t seem to be firing the live to the pump when it should be. The black wire in the stat is the one with mains and the brown goes back to the danfoss controller into the bottom of number 3which the live for the pump is also connected

Maybe i am going nuts but #3 connector is empty?

I assume this system has been working fine and that you haven't changed anything? If so, something has broken or failed.
If not, and you've changed something, then get an electrician in to sort it for you.

Could be loose wire has arced out in the conn box. Hard to say really.


#3 being empty when you say its a pump live is odd......

Edit: #3 has two in the bottom. (Hard to see on the photo :) )

Edit #2: Have you checked that 240v is being switched through the stat?
 
Maybe i am going nuts but #3 connector is empty?

I assume this system has been working fine and that you haven't changed anything? If so, something has broken or failed.
If not, and you've changed something, then get an electrician in to sort it for you.

Could be loose wire has arced out in the conn box. Hard to say really.


#3 being empty when you say its a pump live is odd......

Edit: #3 has two in the bottom. (Hard to see on the photo :) )

Edit #2: Have you checked that 240v is being switched through the stat?

It’s a new build house horrendous issues with contractor hence having to sort any issues out myself, the pump has never been required as no fire ever lit until recently. The two browns in bottom of number 3 one comes from stat and the other goes to the live connection to the pump, haven’t checked that 240 is being switched have an electrician booked to come have a look but thought if it was something straight forward coulda sorted myself
 
It’s a new build house horrendous issues with contractor hence having to sort any issues out myself, the pump has never been required as no fire ever lit until recently. The two browns in bottom of number 3 one comes from stat and the other goes to the live connection to the pump, haven’t checked that 240 is being switched have an electrician booked to come have a look but thought if it was something straight forward coulda sorted myself

Ah, that explains it.

As someone who has spent the last two decades chasing snags and contractor incompetency on my own "new build" house, i would find a good plumber/heating engineer (not easy) to snag the system.

In my case, i ended up redoing half of the plumbing and most of the boiler electrics.



Edit: don't tell the electrician to "fix the problem". Ask him to check the wiring on the heating system (all of it).

:)
 
It’s a new build house
Oh dear, well first thing electrician will do is rewire that stat with 3 core and earth. You don't use green/yellow for live unless over sleeved and even then an earth wire must be run even if not used to any fixed unit. Unless it is extra low voltage.

My son did have pipe stats on his narrow boat to run the pumps, since water could boil if pumps did not run, they were battery powered so no chance of power failure and duplicated.

So you want some one who can show he is trained so you can give the builder the bill, and he (person doing correction) has some clout.

With narrow boat no option, but with houses normally arranged so thermo syphon will circulate water, so no chance of water boiling, and also header tanks either metal or thermal setting plastic not thermal plastic or this
_44346269_203tank.jpg
can happen. I think there is an organisation called HETAS part of Part J of the building regulations. There are clear errors so you want to be safe.
 
Oh dear, well first thing electrician will do is rewire that stat with 3 core and earth.
It already has 3 core + E - hence the Brown and Black - which makes it even dafter.


So, where is the green/yellow wire connected at the other end?

If it has been connected to an earth terminal then it can be expected there has been a short which might have damaged the thermostat.

EDIT - Picture altered from original which had the wrong g/y arrowed - see later post.

upload_2021-12-3_19-21-57.png
 
Last edited:
It already has 3 core + E - hence the Brown and Black - which makes it even dafter.


So, where is the green/yellow wire connected at the other end?

If it has been connected to an earth terminal then it can be expected there has been a short which might have damaged the thermostat.

View attachment 252991
Hi thanks for the reply the earth is attached to the bottom right hand side of the stat. the black wire which is cut is the cable for the pump the only connections it has is brown,blue and earth. I’ve attached couple better images the first is the pumps cable and the second is the stat connection the neutral is not connected on either end of the stat thanks
 

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