Hive wired wrong?

[CalzorSuzay]

I had Hive installed about June and all seemed good.

Now in recent times (as we use the CH) I've noticed the CH stays on i.e. the boiler goes through the motions of heating the water turning off for a while presumably as it reaches it's own temperature and then coming back on again 5-10 minutes later regardless of what the thermostat is saying. Also looking at the light on the Hive box it's basically saying the heating is off and the pump acts as normal, runs for a while after the boiler then cuts out.
The HW (tank) appears to work normally.

Now from poking about the internet this looked to be a CH 3 port valve issue and the valve and electronic motor may need replacing because they're stuck or the motor is worn out.

Up until now I've been cutting the power in the airing cupboard where everything but the boiler is and during this process I can hear the CH 3 port valve rotate back, reset itself and the heating stops until the Hive thermostat kicks in as it gets below threshold etc but...

A few days ago I noticed if I place a call (boost or on) to the HW I can hear the CH 3 port valve rotate back and then if I turn the HW off or leave it to run the CH is ok and doesn't just run constantly.

For me this implies the CH 3 port valve is working as it rotates back and forth not stuck, could the wiring be incorrect or could it still point to a faulty CH 3 port valve?

 

[jackthom]

Because the 3 port valve is happily returning to it's rest position when the power is cut this sounds more like some sort of odd wiring problem or the switching inside the hive receiver is somehow getting stuck ON until it gets a power reset.

Someone who has a multimeter and knows how to use it is needed. The original installer should probably sort it out.

 

[CalzorSuzay]

I've had a British Gas engineer back round and he spent about 4 hours fannying around with it to come to the conclusion it's probably the CH 3 port valve, although...

At one point he swopped out the Honeywell motor for a new one and it still played up, then after lot's of mucking about 'dry wired' a Drayton one in which doesn't fit the valve and then this worked normally as in the boiler turned off when requested.

Conclusion was replace valve & motor for £250, I needed a bunch of other work done like powerflush, rad valves replaced, new rad, towel rad etc so have a local plumber coming to do it plus the valve & motor replaced (£84) so hoping he can sort it our rather than the bungling B Gas guys.

 

[St0rmer66]

Do you by chance have a Worcester Greenstar Ri?

 

[CalzorSuzay]

No it's a Glow Worm Micro 60FF.

 

[St0rmer66]

Same problem affects them too!

You can DIY it with a capacitor or resistor from an electrical shop (few quid at most) and fit it between the orange and blue wires in the wiring centre (no need to go into the boiler so can do it yourself). Or get the glowworm one (no different, probably more expensive) and fit yourself in the same place I described.

 

[CalzorSuzay]

Sounds similar but not quite the same perhaps.

The 3 port valve closes when I initially call for HW not when it's satisfied, still think it's the same issue?

Also I thought the boiler needed a 240v to kick in or can this stray voltage be enough to start it?

 

[CalzorSuzay]

Do you know what capacitor I need i.e. spec of it?

 

[jackthom]

Try a 270k Ohms, 0.25 Watt(higher wattage is OK) resistor across Orange and Blue.

That should drop the stray voltage to around half it's present value and hopefully stop the boiler firing when it shouldn't be.


It may need some experimentation with resistor values depending on the input impedance and sensitivity of the boiler switched live.

 

[CalzorSuzay]

With the wiring centre cover off there's only 1 orange wire and that comes from the 3 port valve but there's a lot of blue wires, is it the same blue one from the 3 port valve?

If so can you literally screw the ends of the capacitor into the wiring centre terminals?

 

[jackthom]

Yes that blue from the valve will be one of many Neutral connections and will do the trick.

I'm suggesting a resistor rather than a capacitor in this case and if its wire ends aren't sufficiently long to extend from orange to blue, maybe you can find a spare position in the wirring centre to help bridge the gap.

 

[Agile]

He suggested a resistor. Although I doubt that 270k would be low enough.

If using a capacitor then 0.01 uF would suffice but it does have to be rated for AC mains to 400 vac and normally would have VDE and other specifications on it.

The blue from the valve connection would be OK.

Tony

 

[CalzorSuzay]

Yeah sorry capacitor was mentioned previously so I just had that in my head when replying.

Here's a photo of the wiring centre although it's been rotated 90° anti clockwise by diynot upload.


As looking at the 'wonky' photo
Left goes to the hive controller
Top left the pump
Top right the thermostat on the cylinder
Right goes to the boiler
Bottom right (black cable) is the 3 port valve
Bottom left is the fused mains feed

Untitled

• CalzorSuzay
• 5 Dec 2014
• 1

So you wire it between the orange lead, top 3rd from right to top 2nd from left? but you say 270k wouldn't be low enough?

 

[jackthom]

He suggested a resistor. Although I doubt that 270k would be low enough.

If using a capacitor then 0.01 uF would suffice but it does have to be rated for AC mains to 400 vac and normally would have VDE and other specifications on it.

The blue from the valve connection would be OK.

Tony

Back of an envelope calculation here but that comes out with a reactance of around 300k. I've seen 0.1uF (or even 0.47 ) recommended for this previously.

I agree a capacitor is more elegant and shouldn't ever get warm.

How about one of these Tony.....?

http://www.maplin.co.uk/p/lcr-metallised-polypropylene-500v-01uf-capacitor-rg23a

 

[jackthom]

So you wire it between the orange lead, top 3rd from right to top 2nd from left? but you say 270k wouldn't be low enough?

Yes that's correct for the wiring, you could use the spare terminal (5 from the left) plus the orange to anchor the component then a wire link across to blue.

The jury is still out on the resistor value and I think you may be better trying the capacitor linked to above on the Maplin website.