Vokera Linea No Hot water

[grill]

Hi All,

Two jobs in oen week. Cant believe my luck!!!!!

Anyway this Vokera had no HW. Boiler is running away and all the Heat is going into the CH so we have a DV problem.

Now i pulled off the motor for the DV and am getting 240 V to it. The arm of the motor doesnt not appear to move when i turn on/off the HW. Im assuming it moves out when HW called for?

The pin in the DV is free to move and i can push it in.

Cant get the motor part until Tuesday so want to be totally certain this is what i need?

Cheers

Grill

 

[DP]

Check out the flowchart oin the manual. Service could also be needed (as described in the manual)

 

[grill]

Yeah i read in the book that the pin is a mechanical device that is pushed in by the motor so im assuming the pin needs to move!!!!!

S

 

[Agile]

Is the burner coming on for DHW?

The pin is pushed IN for DHW unlike most boilers.

If will only push in if demand senced for hot water.

You can test motor by reversing OUTER connections. It drives to the next position and then stops.

Tony

 

[grill]

Hi Tony,

Yeah when you run the HW tap the boiler kicks in and runs away merrily but i pulled the motor off to see if any movement and nothing. If you run the tap like this then the rads start to heat up.

Am i making a serious assumption that with the motor off the DV when i turn on the HW tap i should see the actuator moving out of the motor?

G

 

[clf-gas]

Vokera Linea, unica and mynute all use the same hydro block, assuming your on a HE.

Yes you should see the motor push, as they all sit in the heating mode.

 

[grill]

Fair enough. Well the motor will be here in the morning so ill let you know how i get on!!!

S

 

[Agile]

While waiting for the postman you could swap the outside leads and see what the motor does.

Being summer you could jam the diverter valve pin IN so that it gives hot water!!!

Tony

 

[grill]

Disaster,

Fitted motor actuator, Ran the HW and nothing really doing. Tiny bit of HW but Ch pipes getting hot.

So i pulled the DV assembly aparta nd cleaned it as best i could and siliconed the pin etc. Now get HW for about 10 secs then goes cold and cycles this way with boiler cycling on and off.

Should i be looking at a blocked sec HE now?

On teh upside i went round to a Vokera Elipse with no HW. Took off the cover, motor actutaor pin had dropped out. Re fitted the pin, job done, took the money and run!!!

G

 

[Agile]

There is no point just fitting a new motor actuator and sitting back.

You need to see what the motor is doing under a DHW and a CH demand.

If its not moving you have to measure the voltage on the pins and work out where the malfunction originates.

It could be a lack of demand, it could be a faulty relay on the PCB if it sits in one divertor valve position, it could be faulty internals in the diverter valve.

as I suggested removing the actuator and pushing in the diverter valve pin would have given useful diagnostic feedback and should have provided hot water.

Tony

 

[grill]

Hi Tony,

I tried that tonight but it was no good and didnt make any difference.

Think i said in my original post that i was getting 230 V to the pins.

When i took the motor out of the box the pin was in and when i plugged it in it powered forward slightly to what i assume is the CH position.

The fact that i am getting some HW would suggest that the motor actuator is doing what it should or maybe just sometimes.

G

 

[DP]

Grill looks like you are making a meal of the fault.

Linea has preheat facility.

With all things on standby on this boiler, the diverter spindle will be in the position that you find it with the motor removed i.e. if you now made heating or HW demand, primary water would flow to radiators.

If you had a good breakfast before leaving the house, you could push the diverter spindle in and hold it in that position while getting someone to run the hot tap. This same person could check if the flow pipe below the boiler stayed cold. If it does, diverter is aOK, if not, I would be stripping the diverter to clean, lube etc. to restore diverter operation. Heck, I would do it anyway as this is an operational part that does cause problems if it is ignored.

Having established above, I would then turn my attention to the diverter motor. When a HW demand is made or boiler powered up, diverter motor runs to depress the diverter spindle as per instructions above para. Result should be hot water at the tap an no heat to the rads. At the end of HW demand or having reached preheat temperature, if CH is demanded, motor runs to allow diverter spindle to push out allowing water to flow to the rads. Diverter motor has three contacts. Middle contact is neutral. Outside contacts power as per demand, one to run the motor to push in the diverter spindle and other contact to run motor to allow said spindle to release.

Motor is fitted with end of travel contacts so it will run until a cam within has turned through quarter turn at which point, one or the other contact interrupts the power and motor comes to a halt. Stop position dictates position of diverter spindle i.e. fully depressed or fully released by virtue of a spring within the diverter manifold.

I hope above explanation helps.

 

[grill]

DP,

Cheers for the feedback. Think i ahev already tried most of what you said though. Have pushed and held the spindle in while running HW but no joy. I then stripped/cleaned and lubed the DV assembly. Got some HW and then cold a while and contunined doing this. Flow pipe was getting hot even with the spindle pushed in. Dont suspect teh motor now as i tried a replacment motor and it was doing the exact same thing.

G

 

[Agile]

I am not sure I have had all the relevant answers but IF the boiler is recognising a demand for DHW, AND the DV motor is correctly moving then the plate may be blocked AND/OR the non return valve at the outlet of the plate primary may be stuck.

Tony

 

[grill]

Tony is that the wee valve you can see at the back of the DV assembly when you remove everything. It seems to be a bit crudded up but i didnt want to poke at it too much as i wasnt sure what it did!!

How does one get that out? Should i just remove the HE and clean as it says its only two screws?

G