Vaillant sine 18 T3W FH has pmt

[mark7041]

Hi I'm in need of some assistance please... I have a vaillant 18 t3w fh combi boiler, the problem started about a week ago when the water and heating would not start up, pilot light is on, the boiler made the usual clicks suggesting a signal was sent but nothing. The morning after I gave it another try and it fired up with no problem. The system has worked fine for a couple of days, (although it has started to make a squeaking noise for a second on start up followed by a sound for a few seconds which resembles air bubbles to me) ran bath water this morning..no problem then afterwards had same problem, no hot water or heating. I gave it a couple of hours and tried it again and yep...it started up again as normal. I have rang a heating engineer today for help, but didnt seem interested, offered to pay him to just come and take a look at it and his diagnosis over the phone was "its a 25 year old boiler so its obviously knackered". Although I'm an engineer in a different field of work, and i'm definitely not a heating engineer, but I don't give up on something until the fat lady say's so. I've bled the rads, in an effort to remove any trapped air. Is the heating guys diagnosis correct? has the fat lady sang her last song? grateful for any advice at this time.

 

[Bunnyman]

U say it makes the usual clicks but could u hear the pump running? When it wouldn't fire

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• Bunnyman
• 26 Mar 2010
• 499

 

[bell824]

bunny you really are top dude when these post very rarley come around but ffs op is it not about time to reconsider a new machine this must be 25 + now.
don't get me wrong though there are some very knowledgable guys like bunny who could fix this but as time goes on and all that!

 

[bell824]

oh and i may just hear the dullcit tones of one very huge woman singing in the background

 

[Bunnyman]

now now bell its old obselete but theres alway bits on ebay!theb sines still a good machine a bit limited by todays standards but better than a new ferroli ideal etc

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• Bunnyman
• 26 Mar 2010
• 499

 

[mark7041]

Thanks for replying to my post guys, it's appreciated. Bunnyman as for the pump firing up when it makes the usual clicks thats a no no, thats whats frustrating me, I was thinking maybe a contact or over heat switch or something may be tired. I have worked with pumps all my working life and this one was replaced around 8 years ago, and the boilers only played up recently. Just wanted to try and save a few bob this side of christmas, I agree she's old and obsolete now but has been so reliable, thats what niggles me. Bell824 Im just happy you are not my GP....Im 70 years young now and maybe you would be convincing my wife to get a new model lol... Thanks for the advice guys.
PS..Bell824 I'll give you the number of that fat lady .

 

[Bunnyman]

right mark if you can hear the relay clicking and pump not running then its the pump at fault.what happens is when you leave it the pump warms up and then will start, you can try replacing the capacitor as an easy cheap fix usually gives the old dog some life, you can take the one off the pump and go maplins they will match it,then reconnect the 2 together this will give the pump the extra kick it needs

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• Bunnyman
• 26 Mar 2010
• 499

 

[The831Bunny]

As Bunnyman said pump running is 1st check. Nothing will happen without the pump running. Don't want to state the obvious, but the boiler has got at least 1 bar pressure in? Vent any air on top of the domestic heat exchanger.

Wonder what boilers in todays market will still be around in 25 years time? I'm changing a pump in an old VCW20 tomorrow, yes should be new boiler Bell, but people can only spend £300 on a repair, not £3000 on a boiler relocation and Part L upgrade. But hopefully they'll remember me when they can

 

[bell824]

mark incase you havn't noticed i am a new(er) vaillant engineer, We as a company do not repair thes appliances any more!

Bunnyman and 831 have entered the fray here and imho these are probably the best guys to advise and/or repair your boiler, they are original vaillant engineers and can repair this blindfolded, i for one know jack poo about them as they can be older than me in some cases.

P.S the fat lady called me and said there is another vaillant that can replace this and it is under the £3000 mark that 831 quoted

 

[Agile]

Mark, perhaps I have missed the answer in all the advice you are being offered.

But have you checked that 230v is being applied to the pump?

Obviously if not then its not going to run.

I am one of the few engineers who will still go and repair these boilers. But I usually find that they have multiple faults as their design is very fault tolerant.

Tony

 

[Bunnyman]

Agile I wished I had made the curry night to meet u! There are LOADS of people mendin these u r not one of the few!

 

[The831Bunny]

P.S the fat lady called me and said there is another vaillant that can replace this and it is under the £3000 mark that 831 quoted

Not if you see the job mate! 10 Trvs to fit, wireless stat/clock in, an old twin wall flue to take out. Upgrade gas to 28mm and relocate boiler in another room for condense/flue. Nah, I'll change the pump this time!

 

[bell824]

But I usually find that they have multiple faults as their design is very fault tolerant.

Tony

fault tollerant, so now it is faulty in more ways than one but it's ok it's tollerant to it!
you still on the beer tony?

 

[Bunnyman]

U tell him 831 it's like water ship down on here lol! We full time engineers blah blah, anyway go to bed its ur wife's birthday!

 

[bell824]

P.S the fat lady called me and said there is another vaillant that can replace this and it is under the £3000 mark that 831 quoted

Not if you see the job mate! 10 Trvs to fit, wireless stat/clock in, an old twin wall flue to take out. Upgrade gas to 28mm and relocate boiler in another room for condense/flue. Nah, I'll change the pump this time!

ahhh i forgot these came with the twin wall option.

not such and easy replacment.

and that there is always the gas upgrade.

Sorry 831