Overheating Vokera Linea 735

[ROSSGR]

As the title suggests I have a overheating Linea 735.

The problem is on heating and hot water. 18month old boiler, system flushed, magnaclean filter fitted.

The overheating noise is not a constant squealing, more like a motion noise, hard to explain, like a steam train engine, noise/quiet/noise quiet/noise/quiet. The noise lasts about 0.5secs, then quiet 0.5secs,noise 0.5secs etc.

It's not the plate HX as when you run the hot water until the noise occurs and quickly shut off the cold inlet the temp display does not show an excessive temperature.

The noise seems to appear over 60degC. Modulation of gas valve ok.

Any thoughts???

 

[twgas]

Is it locking out on overheat or just sounds like it's overheating?

 

[ROSSGR]

Not locking out just sounds like overheating......

 

[kevplumb]

err not chuff chuff chuff

 

[twgas]

Possibly a flue problem, but I'm sure there could be other things causing your sort of noise, gas valve, pump cr4p in system (just because you've had pf and mc don't dismiss it)
most likely need a RGI.

 

[twgas]

err not chuff chuff chuff

Do you think he lives near a railway.

 

[kevplumb]

na but remember the celtic when the CC seals went

twas just a thought yer sarky git

not talkin to you any more so there

 

[nickso]

first thing to check is the fan and venturi. if the fan impellor or venturi's are choked then it can have a big effect on this boiler. the analogue APS adjusts the burner pressure so even a little bit of crap in the fan/venturi will have an effect on the boiler operation.

 

[ROSSGR]

I'm BG!! No jokes req as it is MY boiler.

Venturi/fan clear, flame not lifting or anything like that. Just a very weird noise.

Fixed a fair few of these but never heard this on any "Noisy" boiler in 8 years......

 

[twgas]

not talkin to you any more so there

yeah, it worked

 

[nickso]

I'm BG!! No jokes req as it is MY boiler.

Venturi/fan clear, flame not lifting or anything like that. Just a very weird noise.

Fixed a fair few of these but never heard this on any "Noisy" boiler in 8 years......

if it's your boiler just ignore it until it breaks properly.

i've been ignoring a lockout on mine for two years now.

 

[Gasinayr]

Renew the changeover valve bobbin and washers common fault with lineas

 

[howmuchlonger08]

try pulling the wire of the mod reg valve when burner on full rate, if noise stops, dirt in main ht ex, if not follow the noise.

 

[ROSSGR]

I will change the bobbin when I get round to stripping it apart. Usually that only rattles on dhw demand though in my experience.

 

[nickso]

I will change the bobbin when I get round to stripping it apart. Usually that only rattles on dhw demand though in my experience.

thats not what rattles.

the fault probably doesn't lie with the diverter anyway. betting good money one or both H/E's are full of carp.