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CH Motorised Valve Radio Interference

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norm norton01/09/2019 12:03:22
119 forum posts
6 photos

I have had a good try at searching the web for a few answers on this, but surprisingly few thoughts about what ought to be a common problem. Most seem to put up with it, or complain that British Gas can't fix it, so I will ask for some thoughts here.

When my gas boiler system motorised valve operates any DAB radio drops out for the 12-15 seconds and now the super fibre internet router also trips off and then does its usual power back on. Funnily enough, the TV seems unaffected. The DAB radio drop out has been going on for a few years.

The various web answers point to thermostats, boiler gas valves and motorised valves as being the guilty objects. But no thoughts on suppression given. It cannot be the roomstat (happens in the Summer), I have a newish Worcester Greenstar boiler, but the interference does coincide with the actuation and duration of the motorised valve when the hot water tank thermostat seems to be ending its call for heat.

Apparently there are resistor/capacitor sets in some motorised valves. Do you think I can try putting a capacitor (or pair) across the motor feed cable supply? What size and type and do I affix a L-E and a N-E pair?

Or have I got to dismantle the motor drive and replace any capacitor that might be lurking in there?

It might be the tankstat if that can take 12-15 seconds to trip off, but unlikely perhaps.


Edited By norm norton on 01/09/2019 12:05:45

pgk pgk01/09/2019 12:09:37
1843 forum posts
288 photos

Accept this isn't my field... but is the radio mains or battery? if mains have you considered just wrapping the wire round a ferrite donut (or is that doughnut?)


David Jupp01/09/2019 12:29:11
732 forum posts
17 photos

I have had a tank stat that started to 'chatter' rather than switch off cleanly. The symptoms were that the pump would cycle rapidly several times at end of water heating. I initially thought issue must be the diverter valve, but no. I bought a new tank stat (different brand, as the problem one wasn't old). Fitting new stat solved the issue.

Not suggesting that is your issue, but tank stats can degrade in odd ways - so don't rule it out as a possible source of problems.

Former Member01/09/2019 12:31:35

[This posting has been removed]

pgk pgk01/09/2019 13:05:31
1843 forum posts
288 photos
Posted by 34046 on 01/09/2019 12:31:35:

donut (or is that doughnut?)

I think that depends which side of the pond you are. wink 2


Hmmm..considered that but its a ring, not a fried bun with jam filling. I'll play safe and call it a torus..


John Haine01/09/2019 14:14:18
3169 forum posts
171 photos

Some years back in another house we had a problem where the pump wouldn't operate. My father and I spent a whole Saturday checking everything with no success. By the following day I realised that the only thing that could be stopping the pump working was a pair of wires that want from the controller up to the HW tank where they entered the motorised valve. I took the cover off this and discovered that the microswitch, to which the wires were connected, had turned to smelly carbon and the wires were open circuited. I replaced the microswitch and all was well again.

Now, while the microswitch was in the process of becoming carbon, there was clearly a lot of arcing going on which would have caused loads of interference, conducted and radiated. So I suggest that you turn off the power and take the cover off the valve, your switch may have done the same.

Bryan Cedar 101/09/2019 14:17:31
46 forum posts
1 photos

Most motorized valves use a synchronous motor so no capacitor needed. The other word you are looking for is Toroid.

Neil Wyatt01/09/2019 15:19:47
17970 forum posts
709 photos
77 articles

Perhaps it's a bagel?


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