Vokera Flowmatic 20-80 RS

[tanker]

Hey,

Wonder if any of you could offer me some advice. I have a Vokera Flowmatic that will not fire up. In my quest to find the problem I have changed the diaphragm on the diverter valve, while this was in need of replacing it didn't remedy the problem.

I know there are various posts on here about similar problems but I've not been able to determine the problem through any of these.

Further investigation showed that the fan did not start up when a call for heating was made, even though the pilot light is lit and the pump was running.

I checked the fan for continuity and also the wires leading to it. I then checked the voltage on terminals on the pcb, all were fine (voltage measured at 240v).
Looking at the connector I then relaised that the pressure differential switch was attached to the same connector. When I pulled out the red/black wire from the switch and turned the boiler on the fan kicked in, however the boiler didn't light.

I tried the remaining two wires of the pressure switch and found that by connecting the blue/black wire the same thing happened. Again the boiler didn't fire up.

I feel that I must be close to understanding what the problem is and wonder if any of you would be able to help me out.

Hope that all made sense

Tank

 

[Agile]

You may think that you are close to understanding the problem!

I think that your blindly fiddling with safety devices could be very dangerous.

One of the Vokeras, perhaps yours, has a design fault which, if the APS is wrongly connected, will allow the gas to be turned on when the fan is not running.

In the circumstances I am not going to give you detailed advice to do anything which requires a competent CORGI to ensure its safe.

Others on this site hide their identity and are less concerned by giving advise which could cause damage or even death.

Tony

 

[tanker]

Thanks for the advice.

As it happens my wife made me call a CORGI guy out. He came earlier this afternoon and told her that it's not worth fixing. I'm not too sure what he said exactly but my wife mentioned the PCB was probably to blame and therefore given it's age we'd be better off going for a new one.

Before I make any decisions are you able to offer me advice as to which combi boilers are regarded as leaders. Money is an issue but if it avoids this happening again then

Cheers

Tank

 

[chrisdicko]

Ive got the same boiler.....and need a new one really.

But the fan should be running all the time! Plus I had the same problems as you, and a British Gas engineer replaced the pressure switch and it fired up every time after that!

 

[nickso]

the fan will run on slow to keep the pilot lit. if its not running slow all the time then the flow switch on the left manifold needs to be looked at.

you need to be able to differentiate between low and high fan speed if you are going to solve the problem. disconnecting random wires will probably not help if you havent even got the fan running on low speed.

 

[tanker]

Nickso,

Thanks for your advice, are you suggesting that the PCB may not be to blame? If so I'm hoping their might be life in the old girl!

The fan does not run at all when the pilot is lit, when you say 'running slow' I presume that this would be continual, not intermitent? Even though the fan is not running the pilot remains lit.

The initail engineer came recommended, I'll see if I can find another for a second opinion. I'd like to grasp an understanding of what the problem is before calling him.

Tank

 

[nickso]

at rest, with the pilot lit the fan should be running. when you open a tap or demand heating the fan should audibly and visually change to a higher speed.

i cant comment on whether or not the pcb is ok. that would need far more information than i think could reasonably be provided on the forum.

 

[Agile]

They are a very simple PCB which hardly ever fail!

Tony

 

[scatmanjohn]

They are a very simple PCB which hardly ever fail!

Tony

I've changed loads....fan relay usually.

 

[Madashell]

Also had problems with the boiler not firing up when heating or DHW is turned on. Paid a local Engineer !!! £ 450.00 to repair the boiler but not much better. After long investigation I foung the fan was full of fluff/dust.
Cleaned fan with small paint bruch and now running perfect for the last 2 years.

Hope this is useful, please let me know if this works on your boiler.



Madashell

 

[scatmanjohn]

Also had problems with the boiler not firing up when heating or DHW is turned on. Paid a local Engineer !!! £ 450.00 to repair the boiler but not much better. After long investigation I foung the fan was full of fluff/dust.
Cleaned fan with small paint bruch and now running perfect for the last 2 years.

Hope this is useful, please let me know if this works on your boiler.



Madashell

How much

Its beyond me why people pay even when the boiler is not repaired.

 

[Agile]

Last week I went to this lady who had paid this fellor over £300 to fix her boiler!

He spent 3½ hours and could not find the fault.

I fixed it at our standard charge of £84 within the hour ( plus a part at £88 ).

It really makes me annoyed when I hear of these incompetents charging more than I do.

Tony

 

[Paul Barker]

I've changed loads....fan relay usually.

I had one set light to itself right infront of me and the customer. All i had done was expose it to see why boiler didn't work, and I think the fire started around the relay. I didn't fix her boiler as I was quite new then and was worried about fan and few other bits so didn't advise her to have the job done. As she had MS I advised her to contact Warm Front. Didn't charge her.

And this is the thanks I got.

She later told another gas fitter that I had set light to her boiler and did he think that "he was one of those rogue traders?"

This gas fitter changed her pcb and using his language "I made £150 out of her, and also got the job to fit her son's boiler"

Well I'm sorry mate but I don't live for "making £150 out of" someone with MS for a 15 minute parts change on a boiler that is going to continue costing her money each year compared to helping her achieve a long term solution to suit her needs.

But I suppose that is why I find this job doesn't pay.

 

[Paul Barker]

Of course nowadays with greater experience I would have confidence to change the pcb. And now know that these boilers can continue for an amaisingly long life. In my experience they have faired better than Worcesters of the same era with their prv on top not connected to anything.

 

[tanker]

Hey all,

Further to my previous posts things haven't got much better

I've had another engineer out who spent about an hour and a half looking at the boiler and came back saying that he couldn't locate the fault. What I can't understand is that if I've paid someone to fix a problem they should be able to find it if getting paid.

I asked him if either the pressure switch or flow device (at the bottom left of the boiler) was faulty. He visually showed me these electrically sound using his multi meter. He also showed me the board saying that it hadn't burnt out. He said that replacing the PCB on a whim wasn't good sense

I'm not sure where this leaves me standing now. It seems that I've had pretty much everything tested. The fan does not run slow at all, only when the flow switch arm presses the lever on the microswitch does the pump start to run (this occurs when the hot water tap is turned on), even then the boiler doesn't fire up. When heat is put on constant nothing happens other then the pump runs.


I'm really fed up now the cold nights are setting in, no heat or hot water is starting to take effect!

Tank