Mid-position valve went BANG / smokin

[Cypermethrin]

I have a Sunvic SP100 programmer, Tower mid-position value, Sunvic cylinder stat and Hortsmann digital room stat connected to a pumped system on a Worcester 23 SBi

Last night my Tower mid-position value shorted out with a bang when the shower pump in the airing cupboard leaked everywhere. The fuse in the main fuse box was tripped. After drying out etc the programmer seems to work - but I replaced the mid-position value which got wet directly with a Sunvic SDMV2304 mid-position value - like to like 4 wire fitting.

Turning on the HW on the programmer - the mid-position value moves to allow HW only as it should.

But turning on CH (either by itself or with HW) results in no movement of the 3 port value. (making sure that both room and cylinder stats were switched ON).

So is the prognosis most likely to be knackered programmer ?? How can I tell if its the room stat or the programmer that's busted ? Thanks

 

[PEDANTICVINDICTIVEMAN]

If there is live to the roomstat when the prog is on for central heating and not live when the prog is off, then that proves prog ok, if the load/call side of the room stat is live when calling for heat then the room stat is ok.

 

[Cypermethrin]

HI - thank for the rapid reply.

Just noticed that turning on CH - boiler does not fire up and also valve does not move..

HOw can I physically check what you suggest ?

If there is live to the roomstat when the prog is on for central heating and not live when the prog is off, then that proves prog ok, if the load/call side of the room stat is live when calling for heat then the room stat is ok.

 

[matt1e]

HI - thank for the rapid reply.

Just noticed that turning on CH - boiler does not fire up and also valve does not move..

HOw can I physically check what you suggest ?

If there is live to the roomstat when the prog is on for central heating and not live when the prog is off, then that proves prog ok, if the load/call side of the room stat is live when calling for heat then the room stat is ok.

you use a multimeter,firstly though I would put money on your central heating fused spur having a 13A fuse fitted, if it has (or did when you had the fault) then I would put more money on the programmer being kaput

matt

 

[Cypermethrin]

hi matt

You are so right - its got a 13A fuse in it !!

Weird that the HW program works fine - but remembering when it went bang only the CH would have be ON - so it may just have fired that circuit.

 

[PEDANTICVINDICTIVEMAN]

Multimeter required to check for voltage, dont trust neon screwdrivers.

 

[herebriefly]

hi matt

You are so right - its got a 13A fuse in it !!

Weird that the HW program works fine - but remembering when it went bang only the CH would have be ON - so it may just have fired that circuit.

Thats the programmer goosed (probably.)

Remove and test with a multimeter.

David.

 

[matt1e]

hi matt

You are so right - its got a 13A fuse in it !!

Weird that the HW program works fine - but remembering when it went bang only the CH would have be ON - so it may just have fired that circuit.

if you have not got a multimeter, to check turn of the spur, lift the programmer off the back plate, link out terminals 1,3,and 5 (here should allready be a link from L to 3, leave this in) then turn on the spur and make sure the room stat is turned up
the valve should open fully to heating then fire the boiler
if it does then replace the programmer, if it doesnt problem is probably roomstat

matt

 

[Cypermethrin]

matt

Sir you and he others on here are fantastic - really appreciate your help.

Now treat me like an idiot (not difficult I know!) when you say "link out terminals 1,3,and 5" - what exactly do you mean ?

Made a mad dash to B&Q tonight to ge replacement programmer in case is that's toasted - picked up a Sunvic 207xls - which apparrently needs to be partly re-wired..... could be a long weekend ahead !

On tha point is the 10 way junction box a separate box to the
programmer - see here
http://www.sunvic.co.uk/unisp.pdf


if it is separae I think all the wiring on my Sunvic sp100 is direcly into the terminals......

hi matt

You are so right - its got a 13A fuse in it !!

Weird that the HW program works fine - but remembering when it went bang only the CH would have be ON - so it may just have fired that circuit.

if you have not got a multimeter, to check turn of the spur, lift the programmer off the back plate, link out terminals 1,3,and 5 (here should allready be a link from L to 3, leave this in) then turn on the spur and make sure the room stat is turned up
the valve should open fully to heating then fire the boiler
if it does then replace the programmer, if it doesnt problem is probably roomstat

matt

 

[Cypermethrin]

Quick update - checked rm stat with multimeter it was fine

Programmer was kaput - installed Sunvic 207xls and after some faffing all is now well.

Thanks to everyone who helped us through - much appreciated