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For the test, can I just remove the plastic caps and apply the terminals here. 
 

I just got a decent jolt trying to put one of the caps back on.., a reminder that I’m working with electricity.

1C69258A-514E-45FD-8406-3DAD64EF6DBC.jpeg

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3 minutes ago, Home Farm said:

For the test, can I just remove the plastic caps and apply the terminals here. 
 

I just got a decent jolt trying to put one of the caps back on.., a reminder that I’m working with electricity.

1C69258A-514E-45FD-8406-3DAD64EF6DBC.jpeg

 

just push the multimeter pin inside the plastic from the top where the wires go in and the black one on the casing or the earth connector. 

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Just now, PeterW said:

And is that with the heating on ..??

 

Yes, the central heating (air source heat pump) is on, and all the underfloor heating thermostats are calling for heat.

 

The Heatmiser central wiring box is also on with all the zones marked as on shown via little lit LEDs.

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1 hour ago, Home Farm said:

Red terminal on live (brown) cable, black terminal on casing and earth reads zero.

Are you sure? You said you got a belt? To get a belt something must exist...

 

On your PCB I can see marked zones, which zone is this valve on - are you getting 240 across live and neutral on the board and the respective zone terminals? The next thing I would then do is confirm that the other end of that wire, i.e. at the valve is delivering power - which I think it will be given you got a jolt.

 

Could wire damage be present anywhere? A damaged neutral/earth but an OK live would result in 0V  across the 2 wires yet still very much live!

 

 

Edited by Carrerahill
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14 minutes ago, Home Farm said:

So why did I have to use the squiggle for this test?

 

Because mains electric is Alternating Current.  The V (dash dash) is Direct current, you'd use that around a car or to test batteries etc.

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3 hours ago, dpmiller said:

Because mains electric is Alternating Current.  The V (dash dash) is Direct current, you'd use that around a car or to test batteries etc.

 

Adding a bit more detail for background: on the AC range the meter will sample over the whole waveform and take an average which best represents the overall voltage, both positive and negative. Effectively it squares the individual voltage samples (so both positive and negative come out positive), averages those, then takes the square root. This is called the RMS value: root mean square. Our standard 230 V AC peaks at about 325 volts but the meter shows the average magnitude of 230 V, or whatever, not the peaks or overall average which is obviously zero over periods much longer than a 1/50th of a second.

 

On the DC range it just takes samples and displays those, probably with a bit of averaging so it's likely that the AC will average out to zero.

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Ok. We’ve determined that power is getting through to the live cable. I took the motor off, and switched off all call for heat from all thermostats.

 

my wide then turned it on while I watched the motor and the spinny thing on the back of the motor is not turning. I waited for a minute. 
 

Fair assumption that it’s the motor that needs replacing?

447150B0-77AE-420F-BBAA-B70C585FB87B.jpeg

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