vokera24/96

[johnboy1943]

my ancient vokera 24/96,is acting up just before xmas,symptoms are
pressure gauge climbs very hi--4 or 5 bar,temperature gauge shoots up,system shuts down,anyone have any idea,many thanks,johnboy

 

[Agile]

Not a lot of information here.

Same on heating as hot water?

Sounds like a blocked heat exchanger or more likely a failed pump!

What are you going to do now?

Tony

 

[johnboy1943]

Tony ,thank you so much ,yes it was the pump,demounted it poured some deterrgent in plug hole and rotated it and off she went ,am very greatfull for good advise ,I owe you 1 or 2 beers ,cheers,

 

[DP]

more likely a failed pump!

NOT in a million years.
On this boiler a failed pump means burner WILL NOT fire.
If the burner does fire, then boiler MUST be looked at and problem sorted.

OP, the pump may be goosed but problem still remains

 

[johnboy1943]

Hi Tony,boiler seems fine now pump is running,behaveing as it should,just to clarify earlier diagnostic,
boiler fired up for perhaps ----3 seconds-----shutdown on its own ,pressure went up to 3 bar,temperature went to 80,or so,then cycle repeated,
I presume because grundfoss pump not working ,it just overheated and shut down ,-----anyhow pump is turning and boiler working as normal,
many thanks again,a hot shower is a beutifull thing thing,johnboy;

 

[DP]

Johnyboy, here is a little info for you.

If your pump is goosed, you make heating or hot water demand, then burner will not fire. If it is, then you have a fault that needs sorting

 

[Agile]

Glad I could help John!

Tony

 

[Agile]

John, you may wonder why DP was saying that it could not be the pump!

He said that because at the left under the pump is a system flow switch which is only activated when the pump is running.

So simple logic would say that the burner cannot fire up because the flow switch would not be activated if the pump is not running. Of course your boiler was firing up even though the pump was not running.

Luckily, with personal experience of your old boiler, I was able to see through that apparent failure of logic.

The reality is that the system flow switch tends to jam in the "on" position on that model. It may be gunged up inside but will probably just be a seized up gland. To repair you may be able to just remove the gland, pull the pin forward and clean it with wire wool and then dry it and apply silicone grease all round it and fit a new gland. Vokera are very good with spares and most parts are still available for your 25 year old boiler.

Ideally though, the diaphragm housing cover should be removed and the inside cleaned out and a new diaphragm fitted.

The flow switch is a safety device and you should therefore aim to get it working soon. It has probably been jammed for many years! It also indicates the you have not had the boiler professionally serviced for a long time!

Modern boilers check that flow switches are in the rest position before the pump is started but boiler design has come on a long way in the last 25 years.

Hope that explains it for you.

Tony Glazier

 

[johnboy1943]

Thanks again tony ,all seems to be working ,cheers johnboy,

 

[Agile]

But have you checked the flow switch is really returning to the best position when pump is not running?

If so then you should electrically as it may be jammed inside.

Its a safety device!

Tony

 

[johnboy1943]

Hi tony ,I checked the flow switch with a multimeter,works fine ,and the little comeing out of the diaphram,also is working,
I notice the little reset button above the 2 gauges comes out,untill it is reset ,presumably as a safety to
stop boiler fireing untill it is sorted,regards johnboy,