WB Junior 24i - no hot water - engineer/plumbers can't help

[hudmb]

Hi,

We had a problem with our boiler in February this year whereby no hot water was delivered when demanded (CH is fine - never been a problem). WB engineer came out and fitted a new flow switch and solved the problem. Everything has been fine since then.

Two weeks ago, the same problem occurred. Engineer came out and fitted a new flow switch. Problem solved.

Four days after this, the problem came back again. WB sent two engineers out who spent five hours trying to solve the problem. They couldn't. They suggested it could be our mixer shower allowing cold water to flow into the hot.

So...we got a plumber out to install a brand new mixer shower and fit a non-return valve to it. We still have no hot water.

WB are saying it's definitely not a problem with the boiler. I'm at the end of my tether. Nothing has changed in our flat, i.e. no new appliances, plumbing etc, and up to things going wrong, we were getting hot water.

Can anyone help? In my opinion if we're not getting hot water, it's a boiler problem if nothing else in the flat has changed and we've got a brand new shower fitted.

Please help!

Thanks

 

[jackthom]

If WB managed to turn on a hot tap near the boiler and that didn't trigger the boiler, I would say there was almost certainly a boiler problem. In those 5 hours did they bite the bullet and try a new PCB?

The flow detector on these is a turbine which generates a signal that you can't really check on a multimeter, so wouldn't you think WB would have a scope available somewhere so they can tell whether it's the flow detector or PCB causing the problem?

 

[hudmb]

Hi - thanks for the reply!

No hot water taps in our flat trigger hot water. The closest is the kitchen sink (about 3 feet away from the boiler) and this doesn't kick in.

Normally you hear a click, then a woosh as it fires up - but not even a click.

They basically had the boiler to bits and back and said they had fitted a new flow switch and PCB (among other things, apparently). Could it be a diverter switch issue?

They also cleaned out a few tubes in the boiler and replaced the pressure gauge and expansion vessel!

 

[gigz]

Quickest way is close the cold inlet valve (second from the right under boiler) and you shouldn't get any water from any hot taps (except for a trickle at first). Or you could try this yourself. Turn the cold inlet tap off, disconnect hot outlet, attach a hose or use a plastic/flexi tap connector into a bucket, then open cold inlet to create a demand. If it fires its a plumbing issue, if it doesn't its the boiler.

 

[hudmb]

Many thanks, gigz.

I have asked that WB come again on Friday as it's been 2 weeks with no hot water and it's very stressful.

When they come back I'll ask them to do what you suggest.

The only thing they didn't seem to look at was the heat exchanger. Could this be an issue?

I'm not a plumber/engineer, so it's difficult for me to challenge them if they just keep saying "it's not a boiler issue".

Thanks for your advice, gigz!

 

[gigz]

Could be any amount of things if its the boiler. WB engineers should be able to fix any boiler problem. Obviously if its a plumbing/mixer issue its not their fault. Have you tried my first suggestion ? Only takes a minute.

 

[hudmb]

Thanks, gigz.

I'm at work at the moment so can't try, but I'm not that technical and don't want to disturb anything to be honest, though I know exactly what you mean I/they should do.

As no plumbing has changed in our flat, I can't believe it's that. But if it was, what plumbing problem could it be? I'm just trying to think ahead for when WB come out again on Friday and say "it's not the boiler" again.

They were 99% sure it was our shower and said it was allowing cold water to flow through the hot pipes into the boiler, thus reducing pressure or battling against the hot. But a plumber fitted a totally new shower plus non return valve and it solved nothing.

My worst fear is ending in a stalemate and the problem is unresolved.

 

[gigz]

Do you have a bath/basin/sink mixer tap/s ?

 

[hudmb]

Yes, the bath, kitchen sink and bathroom sink are all mixer taps.

 

[gigz]

If they have isolating valves on them, isolate the cold on each one see if that works. Know all this sounds like a right chew but its the easiest and quickest way of proving where your fault lies. Good luck.

 

[hudmb]

Thank you!

Is an isolating valve something I should be able to see, or is it within the tap fitting. I can't see any taps/valves to isolate.

A non return valve was fitted to the new shower unit. Are you saying we could fit non return valves to the mixer taps too?

 

[gigz]

Isolators are usually the slotted type, use a flat screwdriver to turn them off (line slot with direction of the flowing water to turn on, across to turn off). You can fit 's to all if you wanted.

 

[hudmb]

Hi,

The bathroom sink is the only mixer tap that has an isolator on the cold water pipe. So I isolated this and tried again...still no joy.

The bath is "boxed in", so for this cold water pipe to be isolated, I'm assuming I'll have to knock all the tiles off the bath panel and do something to the taps? Unless this can be done without the mess and fuss?

There's no isolator on the kitchen sink cold pipe.

Thanks!

 

[hudmb]

Hi everyone,

I thought I'd update everyone.

So, the problem did turn out to be the shower mixer unit. It was allowing water to flow the wrong way and it kept on damaging the flow turbine.

Of course, the engineers replaced the flow turbine whilst the old shower was still in place, so the shower broke it.

They came again AFTER the new shower had been fitted and replaced the flow turbine again and it all now works!

Thanks so much for everyone's help!

 

[Agile]

So you see that the advice we have given has been totally correct.

Difficult to imagine why the Worcs engineers were so slow to identify the problem though.

I encounter one like that every few months. Most often after some plumbing work has been done.

The last one was a little different. The owner had bought and fitted a new kitchen mixer tap. It was faulty inside and had a full bore path between the hot and cold inlets!

Tony