water gets hot then goes cold, help please.

[waynemp]

hi, i have a vokera linea24 combi boiler, its about 4 maybe 5 years old. my problem is the water!! the heating seems fine but the water keeps going hot and cold so for example when taking a shower its a case of get wet while its warm, lather up while its cold then rinse off when it gets warm again.. pretty annoying. when i turn on the hot tap we can hear a 'chugging' noise from the boiler and the pressure needle skips up and down..(although that is intermittant, the water goes cold evn when its not chugging)

ive had a plumber out but he didnt seem to be able to shed much light and stated that if i put it right through a process of elimination then it would prob be cheaper to just fit a new combi boiler which he can do for about £700.00 (i know him so think thats prob cheap) any advice / help would be great, didnt envisage forking out for a new boiler so soon after xmas

 

[waynemp]

I have the boiler serviced regularly and this doesnt just accur in the shower its a problem when running hot water from anywhere in the house.

The boiler is about 5 yrs old and has already had a new pcb, a new gas inlet valve and new thermisters in that period. I seem to get problems every 2 years.

The last time it was serviced my plumber told it might be an idea to move the boiler as its at the top of my cellar steps, prob the coldest part of the house. He seems baffled why I have problems every 2 ish years.

This is the 3rd boiler ive had in the 13 years ive lived in this house.

 

[Corgigrouch]

On the face of it it sounds like a mucky secondary heat exchanger... some folk like to clean them, I'd toss it in the bin and fit a new one, have a look at the heating water for perhaps needing a flush and a spirovent magnabooster on the return pipe..

Or it could be another dodgy themistor. Had one on friday with the same symptoms... BG said powerflush! another guy said change the boiler, turned out to be a dodgy thermistor, read perfectly when tested with a meter but had a poor contact insid and sometimes went open circuit..

 

[BingoBongo]

Run the hw and hold the central heating pipe or check the first radiator and see if it gets hot

 

[waynemp]

first radiator stayed hot, almost too hot to touch also second radiator stayed hot too.

 

[BingoBongo]

Service kit and service req most likely.if your capable take the case off and check the divertor motor is moving.just a circlip holding it in place.sometimes it leaks at the pin and takes out the motor

 

[waynemp]

its just been serviced, the guy that did it mentioned a part was prob sticking i cant remember what it was called but he said he had sorted it out. im sure he said it was a small part that swithces to tell the boiler when to run hot etc he said that was sticking. hes been back out to it and cant find anything wrong and the boiler shows no fault code. he actually advised me and i quote 'it may only be 5 years old lad but its still a vokera linea, i would lean towards getting it replaced'.. those where his words of choice. he was also quick to point out that he wasnt trying to get business and to feel free to get anyone i wanted to replace it.. i do trust the guy and he seemed pretty honest, hes been back twice to check it and hasnt charged me a penny..

 

[Corgigrouch]

Doh... Even I get it wrong now and again.

A five year old boiler is worth repairing

 

[BingoBongo]

Service kit not always fitted on service.trust mr get the kit fitted and get the motor checked/changed

 

[waynemp]

service kit done and motor checked.. worked fine for about 4 days after that now its back to running hot and cold. the plumber that came mentioned that the divertor seemed to be sticking, he sorted that while doing the service etc. doing my head in now dunno if its wise to keep throwing money at the thing.

 

[BingoBongo]

you may need to call him back or call someone else.usually they leak from the pin and take out the motor.if you are confident you could check the motor yourself it only held on by a circlip

 

[waynemp]

yeah i think ill get a second opninion off a different plumber, maybe my usual guy isn,t up to repairing boilers.. thx for the advice and ill let you know how i get on.

 

[Ray84]

...............just waiting to get shot down in flames from another user but!

if youve had the thermistor changed. run the hot water from your tap(not the shower) see if it does the same. if it does do the same then allow the boiler to heat up and then at the second it cuts out turn the black inlet valve (far right) to the 9pm position(isolates the hot water). The display will then read a temperature of the system water. if its 90 or above your heat plate is most probably choked(nackerered)
if not it could be one of the above possible faults but even if it is a heat plate i think its worth repairing.
Why not concider a fixed price repair from the gas board or vokera? its a simple fault diagnosis if you have the right engineer.
Definitly not ready for the scrap heap

Ray

 

[Agile]

Since the diverter valve service kit has been fitted does it still heat the rads when you take hot water?

Tony

 

[waynemp]

yes the radiators still heat up just fine. ive had a second opinion and that guy seemed to think it would deffo be the divertor as its a common thing on these boilers? he did give it a thorough going over and made his diagnosis after doing so. it doesnt matter where i run the hot water from the boiler still cuts out. he's quoted me £145.00 to do the repairs but insisted he couldnt guarantee that it would fix it, which leads me to think id be better paying the £165 fixed guarantee repair fee from british gas or indeed vokera.

thanks for the advise guys, i guess paying out £165.00 now is better than forking out £650.00 for a new boiler even it only lasts a few more years.