Worcester 12/14 won't turn burner off

[iceman66]

Had heatslave tank replaced by plumber. nown boiler running until over heat limit reached - very dangerous temps with two kids!
Plumber came back and replaced both heatslave thermostat and over limit stat.
Control for heating OK, works, trips etc. But on hot water you can turn dial and hear 'click' but whereas before we could control temp, and full anti-clockwise would stop burner operation, now it still 'clicks' as if relay making, but just keeps getting to over limit and no amount of full anti-clockwise will stop burner.
Any thoughts please as it all worked fine before and have had two new stats and heatslave tank (which developed a leak)
Any clues please!!??

 

[Agile]

I cannot guess whats happenned but it sounds as if a sensor lead may have been dislodged.

It sounds as if you may need a more competent or careful engineer.

But as a first step you should call him back.

Tony

 

[iceman66]

Thanks for that, but he's been back three times and now has said we've got to get a Worcester expert in!
All this against a quote in writing to investigate fault, replace parts as required and leave in working order. already they want exrta money on top of quoted price to cover 'unforeseen extras'

 

[Agile]

Whilst I cannot assume whats wrong it does sound as he has dissturbed something but does not have the competence to see what he has done.

You have not said what he has charged but in my view, unless it was cheap, I think you should ask for a partial refund.

I would never leave a customer with a charged for job which is still not working.

Tony

 

[iceman66]

Hi Tony,
thanks again.
No it wasn't cheap! £568.00 and he was sent via a disabled support charity that does brilliant work on most things, but we have no safe boiler!

 

[Tommowlaes]

Sounds like the flow switch is sticking or faulty.

 

[oilman]

Is this a gas or oil boiler?

 

[iceman66]

It's a Worcester Bosch Heatslave 12/14 RS Oil Combi.

Strangely, whatever the plumber did today (fitted new hot water thermostat), the burner comes on up to over limit temp- then cuts out. But now neither the central heating or hot water rotary temp controls have any input to temp control or ability to turn off boiler by going fully anti clockwise!
Also, I've noticed that even though I've selected DMH and CH 'progammes on' (LED on controllers are lit and checked we are not in a timed out phase by using the 'on' option), the burner comes on, DHW up to scalding and CH is completely cold!!! - No flow to radiators.
Finally, the pressure gauge is going from 1.5ish bar at rest to 4 bar ish during use.
It seems like there might even be a blockage maybe?
or a 'switchover' function missing.
Curious we've got scalding ot water, no rotary control of burner or temp and no central heating flow of hot water - all rads are cold.
Pump appears to running as we get bags of scalding DHW - although it may be not pump controlled?
Sorry, used to dabble in sinks, taps etc, but never boilers and now in wheelchair, can't get 'dpwn and dirty'
But would love some advice in case next 'engineer' goes all around houses and still never arrives at fix.

 

[Boilerman2]

It's GOT to be the Flow Switch located on the Cold main feeding the plate HE stuck in the run position, this will overide all other thermostats except overheat, and will prevent the Radiators from working Get the Flow switch looked at, (2 minuite job!!)

 

[iceman66]

Thanks Boilerman2,

Sorry to be a pain! Reading Installation manual it says flowswitch would have to have been removed to replace heatslave tank. In section on changing the flow switch it states method.
Have checked connections are not reversed on control board (I can reach that!), could he have 'dismantled' the flow switch and reassembled it in wrong order?
Book mentions placement of washers, plastic body etc.
If that's a possibility, it looks like even a 'wheelchairy' could buy and swap flow switch - crazy or possible?
Thanks for help in narrowing down fault.

 

[holty]

it basically a paddle switch.and is as it sounds.basically when running water is passed through .the paddle hits the microswitch.its basically a very simple test with a multimeter.and am surprised that anyone that has taken on a task of stripping and then reassembling this boiler hasnt got an idea of what the problem is.personally i think there leak machines at about 10 year old and wouldnt bother wasting customers money.

 

[iceman66]

Thanks Holty,

Only trouble is the £568 was our money, not from charity support, we've funded repair because new boiler was quoted at between £2,500 and £3,000 and ain't got that kind of money.

Is the multimeter test an ohm value or open circuit, or a defined value at a certain 'throw'?
Any ideas please.
Thanks again

 

[holty]

continuity test.better still unplug,the flow switch from the board.but in honesty this should be done by who you have paid.not yourself.also i would, if you could. start saving for another boiler as i hate to say it down these parts the aggressive water seems to kill these boilers.

 

[East Kent Coastal]

Only trouble is the £568 was our money, not from charity support, we've funded repair

He's charging you how much for not fixing your boiler?! I'd be seeing someone about that if I were you...

 

[holty]

He's charging you how much for not fixing your boiler?! I'd be seeing someone about that if I were you...

wait to you see the cost of the heatslave tank and the job involved.yet no excuse for leaving it as it is.OP have to say if the guy who did this work had any sense then he would have at least called worcester technical.this all sounds a very bit odd.