No hot water after tap washer change.

[jimbobaroo2]

Hi Guys.

Once again l'm seeking your good advice about my naff Saunier Duval 30e Combi.
Yesterday l changed a leaking tap washer on the hot water bath tap, so l turned off the stop cock on the rising main to do the job.
Turned the stop cock back on , then found out there's now no hot water when the hot water taps are turned on, only cold water coming out.
Central heating working fine.
When taps turned on , the hot water demand light doesn't come on and the boiler doesn't fire up etc.
We've had a problem in the past were we've had to run the tap full blast for sometime in order for it to start warming up, then its been ok, on several occasions.
In the past l have changed the D.H.W. micro switch as it was a straight forward job , but didn't make much difference.

I'm now thinking it might be the assembly the switch is attached to that might be the problem, ie stuck ( is it the hot water demand valve ?? )

Anyone got any other ideas please what the problem might be.

Any feed back/help much appreciated.

Bob.[/i][/b]

 

[persiamomolti]

I don`t know a lot about boilers but my guess would be the hot water flow switch is faulty. Sure other more experienced engineers will be hovering shortly to shoot me down in flames, that`s my guess though, for what it`s worth.

 

[kevplumb]

unclip the dhw switch and see if the pin is moving when you run a tap

View media item 15527

 

[jimbobaroo2]

I don`t know a lot about boilers but my guess would be the hot water flow switch is faulty. Sure other more experienced engineers will be hovering shortly to shoot me down in flames, that`s my guess though, for what it`s worth.

HI persiamomolti. I guessed that might be the problem but not sure of its exact name. thanks for the quick reply.

 

[jimbobaroo2]

unclip the dhw switch and see if the pin is moving when you run a tap

View media item 15527

Hi Kevplumb.
Thanks for the reply.
I've followed your advice and done some experimenting. This is what I've discovered :-

The pin didn't move too well at first so freed it of with pliers and WD40. Now moves Ok ish when tap's turned on and off.
Checked the microswitch by pushing in with an electricains small screwdriver, and, with the power switched on the boiler fired up so no problem there. ( I know. Shouldn't mess around in a boiler with the boiler's power on, but had to check the switch. )

To me it appears that the pin isn't coming out far enough to trigger the microswitch. Any one heard of this problem before ???
What is the remedy ?? Is it a new pressure flow switch or another micro switch ??
If its a new pressure flow switch are they easy enough for a DIYer to change ??

Thanks again for any help.
Bob

P.S. Can't understand how this problem started just by turning the stopcock of.

 

[kevplumb]

there is a rubber diaphram inside the housing behind the pin might be stretched

can't remember if there is an inlet filter on the water on these

 

[jimbobaroo2]

there is a rubber diaphram inside the housing behind the pin might be stretched

can't remember if there is an inlet filter on the water on these

Hi again Kevplumb.

Do you or anyone else know if the diaphram can be changed easily or do l need to replace the whole unit/valve??
Is it a DIY job or more complicated ??
If its easy to do , is there any special precautions etc l need to know

 

[Agile]

I find them relatively straightforward but then I repair boiler for a living.

Tony