Vokera Linea 24 Hot water problems.

[emailpatch]

I have a Linea 24 boiler approximately 4 years old, recently I have experienced hot water problems, I have read numerous posts on this site and convinced myself that the problem was with the secondary (plate HE), the central heating would work fine and when we wanted hot water the taps would run luke warm then cold constantly. After taking advice from this site I checked the boiler display when the water went cold and it read 93 and the main gas burners went out, so I thought it was the secondary HE. I again followed instruction, stripped it out and the cleaned the HE with all the recommended solutions until both sides of the internal plates were gleaming. I then reassembled and all seamed well until I got an error 7 message with quickly cleared, since then however I still have lack of hot water now and then on the domestic side but now the burners and the bioler are still running even with no central heating on, can someone explain why I have no hot water when the burners are on please?

 

[Agile]

If the burner is on then heat is being inputted and it has to go somewhere!

If its not going into the hot water then its going into the rads.

Leave boiler off for an hour then run hot water and see if rads heat up.

This would imply a diverter valve fault, probably motor actuator or PCB.

Tony

 

[emailpatch]

Thanks for the reply, turned the hot tap on again and the boiler fired up, water ran warm then cold but the bolier kept running all the time, at least two rads began to get warm, if it was a faulty pcb why would the tap fire up the boiler on the hot water side? just trying to understand not question your reply. Thanks again. Took your advice left an hour or so and tried again, boiler fired up on turning tap this time hot water and no warm rads, I hate intermiitant faults.

 

[emailpatch]

Had the heating on this morning, worked fine, went to run a bath and while watching the boiler display I noticed that the boiler kept displaying error 7 for a split second then it fired up again then error 7 again until after about 10 seconds it just said error seven and went out, it reset after 30 seconds and then run a full bath of hot water. Could this be my problem? If so what is this, the manual just says consult an engineer.
Thanks in advance.

 

[nickso]

code 7 is primary thermistor open circuit i think.

check for a loose connection and replace it if you find nowt.

 

[emailpatch]

Could the thermistors be the cause of my original problem (lack of hot water) after cleaning the HE the hot water did work fine most of the time and after reading back through some posts people have suggested this as a cause for the lack of hot water. What do the thermistors do?
Thanks in advance again
Steve.

 

[gas4you]

thats right nickso code 7* points to flow or return ntc or too much heat

 

[nickso]

Could the thermistors be the cause of my original problem (lack of hot water) after cleaning the HE the hot water did work fine most of the time and after reading back through some posts people have suggested this as a cause for the lack of hot water. What do the thermistors do?
Thanks in advance again


Steve.

the thermistors are what the boiler uses to read the water temperature of the system water or dhw or both depending on the boiler.

yours has a primary and dhw thermistor. as code 7 says its the primary thermistor check/change that first. they are not expensive.

 

[scatmanjohn]

I had a Linea last week that was running luke warm water to cold constantly.

The fault was with the diverter motor.

It had got water in it and was pushing the diverter push rod in and out during a demand.

Worth looking at if it still doesn't work after you change the primary thermistor.

 

[emailpatch]

Thanks, had the cover off again and checked the wiring, all seems fine. Am i right in thinking that the primary sensor controls the central heating temperature then? Unusually (touch wood) I have had no problems at all with the rads getting warm just the HW. All working fine at the moment will post again when the problem revisits if the need arises.

 

[gas4you]

does the ch flow get hot when heating off and hot taps on? If so refer back to scatmanjohn post.

 

[locosaki1978]

To check the thermistor disconnect the leads and check the resistance,when the boiler(water) is cold you should have a reading of 15 ohms,if your not getting this and it's a lot lower that could explain your lack of hot water,i.e resistance is down therefore pcb thinks the water temp is hot and not sending full voltage to the modureg on the gas valve.Failing that remove the ntc from the C/H and fit it in the H/W outlet.

 

[emailpatch]

More info!

Water again running cold then hot cold ect, burner definetly still running with central heating turned off. I am unable to say where the water is going as the heating was on just previously but obviously as previous posts have suggested it must be going to the rads. Definately a clicking noise as the hot water outlet pipe turns from hot to cold ect. Is this then a fault with the diverter value or could something else be telling the value to open close ect?
Also does the valve come as one complete unit?
Thanks again in advance
Steve.

 

[scatmanjohn]

You can take the motor off the end and watch what happens.

Is it moving in and out while you are running the hot tap?


When you take it off is there any signs of a water leak on the long tube that it is fastened to?

 

[emailpatch]

The problem is its not a constant problem, 1 minute later after turning the tap on and off a couple of times it stopped clicking and hey presto Hot water! do they go intermittent or usually fail altogether?