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UFH stopped working


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On 29/01/2020 at 17:41, ProDave said:

I don't suppose you have any documentation how it is wired?


No we don’t because it was fitted to replace an oil boiler system we have for the ASHP, but not what’s wired to what.

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3 minutes ago, dpmiller said:

the valve works when it gets a supply of electrical power. You haven't yet confirmed that this is happening. Once you do this than you can confirm that either the valve (it's motor on top) has failed, or instead part of the control circuitry upstream (UFH wiring centre/ stats/ timeswitch/ ASHP controller even maybe)


Right. We our plumber coming in next week to do some unrelated pipework. I’ll ask him to have a look at the valve and we’ll see whether it’s getting electricity supply.

 

Is it possible the valve has “blown”?

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1 minute ago, Nickfromwales said:

Basically what we need to know is, if, when the heating is turned on / off, does the brown wire get energised / de-energised ? If it does then the controls that are giving the signal are fine and the motorised head is duff. 

 OK. That’s clear enough.

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2 minutes ago, Home Farm said:

 OK. That’s clear enough.

To clarify ( for others ) it's the brown wire that feeds the motorised valve actuator head that I'm referring to. That will be a 5-wire arrangement;

  1. Brown = Call for heat / demand - which when energised spins the stepper motor and actuates the valve body
  2. Blue = Neutral
  3. Green / Yellow = Earth
  4. Orange = Common
  5. Grey = Switched live back to the heating system ( activated by the valve getting to 100% open and the actuator arm striking a micro-switch in the head thus completing the circuit )

4&5 can be wired either way around without affecting operation. 

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24 minutes ago, Home Farm said:


Right. We our plumber coming in next week to do some unrelated pipework. I’ll ask him to have a look at the valve and we’ll see whether it’s getting electricity supply.

 

Is it possible the valve has “blown”?

Yes, the motors are known to fail and are replaceable.

 

Hopefully your plumber also does electric. Not all do...

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I asked earlier if you have a multimeter?  If you do, follow the cable coming out of the valve head it will go to a junction box or a wiring centre.  Measure with the multimeter set to ac volts between the brown and the blue core.  If there is no voltage, it is a control fault.  If there is 240V there and the valve is not opening then the motor has gone and you need to replace the valve head.

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Thanks for all the input above. I was going to action stuff today and woke up to all our thermostats and Heatmiser central wiring box dead. I’m guessing this was all interconnected. Some sort of electrical issue. 

 

Trying to get an electrician out to help us and test what’s gone wrong. 
 

On that note, we have new Neostat thermostats - do we have to go with a Heatmiser central wiring box or will another brand work Ok?

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On 01/02/2020 at 09:09, ProDave said:

I asked earlier if you have a multimeter?  If you do, follow the cable coming out of the valve head it will go to a junction box or a wiring centre.  Measure with the multimeter set to ac volts between the brown and the blue core.  If there is no voltage, it is a control fault.  If there is 240V there and the valve is not opening then the motor has gone and you need to replace the valve head.


No, I don’t have a multimeter.

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I spoke to the support team at Heatmiser and they suggested that perhaps the motorised valve shorted out the circuit board on the wire control box.

 

Does that sound remotely viable?

 

I’ve ordered my multimeter and will test the motorised valve when it arrives. I will also replace the fuse in the heat miser to see whether that allows it to turn back on

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18 minutes ago, Home Farm said:

I spoke to the support team at Heatmiser and they suggested that perhaps the motorised valve shorted out the circuit board on the wire control box.

 

Does that sound remotely viable?

 

I’ve ordered my multimeter and will test the motorised valve when it arrives. I will also replace the fuse in the heat miser to see whether that allows it to turn back on


Unlikely. From memory the boards have a number of fuses to stop that sort of thing happening, wouldn’t be the first time though I’ve seen one wired wrong ...

 

And sorry if I sound negative but I find Heatmiser to be expensive rubbish that us usually has to be ripped out when one component goes wrong as the units aren’t backward compatible more than 3-4 years. 

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On 29/01/2020 at 15:37, Home Farm said:

Can I leave it on open as opposed to auto? Do you think this could be the cause?

 

 

My guess is that valve is only meant to open when the UFH calls for heat. You might find it works fine left open but it may heat the UFH manifold and pipework unnecessarily when the rads are calling for heat.

 

 

Edited by Temp
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On 01/02/2020 at 09:09, ProDave said:

I asked earlier if you have a multimeter?  If you do, follow the cable coming out of the valve head it will go to a junction box or a wiring centre.  Measure with the multimeter set to ac volts between the brown and the blue core.  If there is no voltage, it is a control fault.  If there is 240V there and the valve is not opening then the motor has gone and you need to replace the valve head.


we have 240v between brown and blue core. 
 

the pipe underneath the motorised valve, leading to the manifold is cold. The pipe above it is hot. 
 

does this indicate having to change the valve motor?

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The Tower units are a cheaper (almost) copy of the Honeywell valves.  You have to take the cover off the actuator and there are then 2 screws that hold the actuator to the valve body.  You can get the Tower units cheap on ebay.  https://www.ebay.co.uk/itm/TOWER-MOTORISED-ZONE-VALVE-ACTUATOR-HEAD-2-PORT-22mm-28mm-CAN-REPLACE-HONEYWELL/392072887213?hash=item5b495d7bad:g:sIAAAOSw37tWAsTx

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2 hours ago, PeterW said:

Standard synchro unit - how handy are you as you can change the motors but full heads are easier. 


Thanks Peter. Handy skills are improving every day :) 

 

what is the head, and why would that be sufficient to address this issue I’m now facing? 

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