Gloworm 30 CXi with hot water but no CHW. Suspect DV valve??

[grill]

Yes guys its me again (and its the same boiler),

Basically in CHW mode the boiler is firing up, rising up to temp rapidly and shutting back down again. When you turn on the hot water tap the boiler runs away merrily and provides hot water. Pump runs in both modes.

I felt the flow pipe below the DV and no heat is getting through (CHW). All heat seems to be getting diverted to the secondary Heat exchanger.

So i pulled the DV motor off and did a buzz test across all three terminals. No buzz. Im assuming this means the motor is burnt out??

I stuck the multimeter into the terminals off the lead and the only reading i got was about 43 Volts. Does that make sense??

It says in the manual that when you have the motor off then turn on a tap and see does the spindle move in and out. Try not to laugh too hard at this but where exactly is the spindle. I could see naff all moving in and out. The only spindle like thing i found was in the hole from where i had just removed the DV motor and it wasn't going anywhere!!

One final schoolboy error i may have made is that i have left the isolation valve closed!!! Only thought about this when i was driving home!!!! Will check it first thing. They werent your usual plastic handle type but basically a spigot with a slot in it. I left them in the vertical position. This was the position that the HW flow was in so im assuming that means open. Feel free to clarify!!!

I hope you enjoyed your cup of tea when reading this and it brought a smile to your dial!!!

Grill

 

[Rob]

What does CHW stand for. Its confusing. CH or HW!

The Actautor shouldn't buzz between terminals. Whats the resistance?

Whats the voltage required to power the motor? Its not about making sense as every boiler is different.

 

[grill]

Sorry rob i meant CH.

Didnt check the resistance on the actuator but will do in the morning. What value should i be looking for?? I thought you can buzz a motor to see if it is burnt out????

Voltage required to power the motor is 230 V.

Spoke to a guy there who reckons there is a problem with the actuator and the lead shorting out on this model. Have you ever heard of this??

P.S im only taking my fledgling steps in this industry so hence all the questions.

grill

 

[Rob]

Im guessing there is 3 wires to the D.V. If none of these are receiving 230v then its likely to be PCB although sounds like a very rare fault. Un forunatley i haven't heard of the faulty leads.

I would suggest double checking the voltage to the DV.

Also make sure the HW flow switch isnt stick closed as this would cause the DV to remain in the HW position.

 

[Agile]

The centre connector is the neutral and 230 vac is applied alternately to the other two according to DHW or CH requirement.

Apart from the Vokera Linea which just has to be different as far as I am aware all other boilers have the pin retracted into the motor for DHW and it rests in this position if there is no call for CH.

The motor resistance is about 2000 ohms but its only connected through ONE outer connector at a time depending on the actuator position when power was disconnected.

Since the power is applied from a SP CO relay its virtually impossible for power not to be applied to one of the connectors.

Tony

 

[grill]

Agile,

So how exactly do i check the resistence of the motor?? Through which terminals. And if it below 2000 then it is shot???

Any where is the best place to check for teh 230 Volts. At teh plug terminal or on the PCB???

And if i aint getting 230 V then is the PCB screwed????

And can i ahve your direct mobile number so i can phone you anytime i run into problems and am standing at a boiler bricking myself bot knowing what to do!!!!!

Grill

 

[Gasguru]

Have a look at page 16 here http://www.biasi.co.uk/pdf/RIVA COMPACT/SERVICE/RIVC0502 EDITION.pdf I think its an identical diverter (wire colours will be different but you get the idea)

 

[Agile]

I wrongly quoted the motor resistance above. It should be about 9.2 K ohms.

The Biasi MI referred to above is incorrect! The 0 v is really on the centre connector and not as shown!

Yes, I know the clever dicks will say that as its AC there is no polarity. Of course thats nonsence because the convention is to measure test points relative to supply neutral or earth.

I would always measure the diverter motor relative to chassis and check EACH connector as that would cover testing for an o/c neutral ( centre ) connection.

Tony

 

[mehran]

i dont know how glow worm fits the dv motor but i have heard that a leaking gland on the dv can blow out the motor if it is fitted on the horizontal axis.

 

[grill]

Well let me shed some light on the whole situtaion. I had forgot to open to the isolation valves again on the Ch circuit. i know I know I know.

Anyway checked out all the circuity etc for th DV motor so thanks for the info.

By the way the pipe out of the bottom out of the heat exchanger into teh condensate trap was leaking. So i pulled the whole thing apart and teh whole thing was blocke dup with brown grit??? What woudl taht be and is taht normal. Anyway i cleaned teh whole thing out and no more leak. Rads work etc etc so another one under my belt and another fine day spent at the Academy of learning boiler problems!!!!

Thanks again for your help

Grill

 

[gas4you]

This is why an annual service is important, especially on a condensing boiler. The trap always has to be removed and flushed clean

 

[mehran]

This is why an annual service is important, especially on a condensing boiler. The trap always has to be removed and flushed clean

what? is a quick a brush down with a hoover not enough?

 

[Agile]

Mehran, whilst stifling the urge to comment on the dreadful treatment of the British servicemen by Iran, you should be aware that a leaking gland will damage the motor actuator whatever the orientation of the actuator.

Tony

 

[kevplumb]

Mehran, whilst stifling the urge to comment on the dreadful treatment of the British servicemen by Iran,

Tony

feel free to comment dingbat the bloke is a stones throw away from me

 

[mehran]

i don't want to get in to the rights or wrong of it all but the 15 are home now.

i been told by two manufacturer that the position of the motor affects the likelihood of it leaking in to the motor and blowing it out, or in to the lead and shorting it out.