Vokera Linea 24 showing 04 error code

[spannor]

Hi Guys,
i won't sound like i know whats happening but heres what i know.
My boiler central heating is working fine or seems to be.
My domestic hot water goes hot and cold and today it has started to flash up the error code 04.
which i know is low pressure of poor flow in system. my system is holding pressure at 1.5 bar so its not a pressure problem.
so my question to you is what is the problem and what can i do myself without paying a fortune.
resetting the boiler gets rid of the fault but then it comes back within minuetes. any help or advise would be appriciated Thanks

 

[nickso]

does it have a flow switch or pressure switch next to the pump?

 

[spannor]

Hi Nickso,

Yes there is a pressure switch next to the pump also it has a Domestic Hot
Water Flow Switch on the cold water inlet. i have changed the flow switch before approx 2 years ago. i have also fitted pressure vessel and MCB also 2 or 3 motorised valves main heat exchanger and cleaned out the domestic heat exchanger. to be honest its been nothing but trouble.

 

[nickso]

if its the pressure switch type disconnect the two wires and run the boiler with the wires shorted together, see if your fault reappears.

 

[spannor]

Thanks Nickso i will give that a try and post my findings

 

[spannor]

Hi Again,
Tried what you recommened by shorting the micro switch wires on the pressure switch and this worked a treat. bought a new micro switch for £15 all seems fine...... ( turned out to be a faulty micro switch)....
thanks for the info

 

[nickso]

good.....but you told me it was a pressure switch not a flow switch.

never mind, its sorted anyway.

 

[Agile]

The only flow switch he mentions is the DHW one!

 

[spannor]

Hi again . it says in the manual that its a pressure switch , like a plunger that comes out and makes contact with the micro switch i understood that was what you was talking about when you said to short the wires out. which i did and the fault went ... But my DHW still goes hot and cold i found out today ((( the fault light doesnt come on and at least i get central heating and some hot water ... any idea why this would happen please mate )) you seem very clued up

 

[nickso]

The only flow switch he mentions is the DHW one!

ah, the legendary glazier reading problem again.

read back, i asked him if it had a pressure switch or a flow switch. he misunderstood and mentioned the dhw flow switch.

 

[nickso]

... But my DHW still goes hot and cold i found out today ((( the fault light doesnt come on and at least i get central heating and some hot water ... any idea why this would happen please mate )) you seem very clued up

a lot of possibles for hot and cold water. the first guess is the DHW thermistor. if you turn on the tap and it starts going hot/cold does the boiler modulate? (burner flame height goes up and down)

 

[Agile]

Hi Nickso,

Yes there is a pressure switch next to the pump also it has a Domestic Hot Water Flow Switch on the cold water inlet. i have changed the flow switch before approx 2 years ago.

He seems to be very sure of what he is telling us!

As the water is still going hot and cold then thats the classic blocked plate heat exchanger which is what I suspected at the start although the error code indicated a red herring.

Tony

 

[spannor]

no it just seems to go out not modulate.
also just to add to this ..
i have just turned the hot tap on in the kitchen full and the temp goes no higher than 30c and when i turn a cold tap on a bit to slow the flow in the boiler the water warms to 41c then flames out then re-ignites ... without turning a cold tap on the water is luke warm at 30c

 

[spannor]

i have had the heat exchanger out before to clean out as read in a forum before or does this not work?

 

[nickso]

Hi Nickso,

Yes there is a pressure switch next to the pump also it has a Domestic Hot Water Flow Switch on the cold water inlet. i have changed the flow switch before approx 2 years ago.

He seems to be very sure of what he is telling us!

As the water is still going hot and cold then thats the classic blocked plate heat exchanger which is what I suspected at the start although the error code indicated a red herring.

Tony

you really are an idiot glazier. i asked if it had a flow switch or pressure switch because the linea can have either depending on the serial number. the dhw flow switch is irrelevant, he misunderstood (which is fine) and i ignored it, why cant you?

the error code wasnt a red herring, you just misunderstood the initial problem as usual.

now that he has confirmed the boiler doesnt modulate i would agree that the PHE is the problem. i would change the non return valve as its bound to gunged up too.