VCW Sine 18 T3

[al-yeti]

Hi, first of all , if its a possible gas problem , i agree that a corgi man should look at this, but iwant some ideas.

Original problem was NO HW except when the CH was on, also the Differential valve was leaking and was replaced. So your thinking divertor valve yes?


But now we have no CH or HW, pump runs but pin from DF is not moving in or out,, it only did it once and then you would have to give a little push to make it go, but then when it did work as normal you could see pin going fully in to operate the valve.


So what you think? obviously the DF has to have enough pressure in order to move the pin out to push the other valve pin in to operate gas, but this seems not to be there. So either i am on the wrong track or you lot are gona put me back on it.

PS i havent spell checked anything i wrote or grammer checked!

 

[Agile]

I think you are describing the pin movement backwards.

As I recall it rests out and locks the gas valve off and retracts to allow it to open.

Sounds like a system flow problem, the thin tubes may be blocked or the pump blocked with debris or running slow.

You dont seem to have said if the diverter valve has been replaced or not.

Whatever happened to your Sime 102 and your Potty Lynx II ???

Tony

 

[kevindgas]

sine 18 now there was a good boiler got to be 25 years old by now a lot of the parts are now obsolete but if you can fix it good on yer

 

[al-yeti]

The potterton was the pump

and the Sime was the stupid frost protection sensor causing heating to stay on thinking it was getting frosty in summer heehee



Ok so you think ciculation? if i was to say pump is ok , what next?

 

[al-yeti]

yes your right but other way around it retracts to cut off gas, makes sense if you lose water pressure then gas should cut out.

 

[al-yeti]

Ok how do i test the pump without just changing it? and if its not the pump what next? ok leave it at pump stage how do i test pump is there a manual test i can do?


Remeber at one point heating was working just fine just no hot water when tap was drawing water , only when heating was running.

No divertor valve not changed, however its confusing as there is a silver block under the boiler almost directly under the gas valve silver in colour , not what some have described being on the far left which i think is the flow switch mechanism

 

[Agile]

I still think that I am right, but I would prefer confirmation from another proper CORGi registered engineer.

Whilst you have not done anything which you are not allowed to do playing with the flow switch which is a gas valve interlock is bordering on CORGI territory.

Tony

 

[al-yeti]

You lost me there? dont you mean according to the manual that the diff valve is the gas interlock which is corgi area???

thought flow switch is mainly all water side, not being cheeky just observing.

 

[ChrisR]

Remove pump head to inspect, see if you can stop it easily.

Diaphragm in flow sensor could be pinholed or the pin seized.

 

[pannierstan]

Wax capsule in divertor valve is stuffed on far left. Remove lid from microswitch assy on top and see if flag moves with demand.

If you select DHW preheat on front of control panel does boiler fire?

Stan

 

[al-yeti]

OK i checked the pump but its spinning fin , turns fine to.



Strange thing is i can defineltey see the pin from diff valve is not pushing the gas valve pin in far enough so i thought water pressure, if you flick the prv then the boiler fires up, but not on full flame either, as the flicking the prv cause slight movement of the diff vavle pin cause it to psuh on the gas valve pin just enough to allow some gas through.


So i am assuming this is a circulation problem, the manual asks to check the venturi, which i havent dealt with before.

 

[al-yeti]

ok when i turn tap on there is no movement on the microswitch assembly , which i assume your talking abot the flow switch on the far left, the divertor valve is all incorporated in this i assume????????/


i checked operation of the valve below the dc solenoid, which has 5 pipes connect to it including the dhw expansion vessle.



any ideas??????????????

 

[al-yeti]

any ideas

 

[Agile]

I really dont think that you have enough experience to attempt to fault find on that model of boiler.

It also worries me that you are not CORGI registered and I suspect that you may not stop at gas related faults. Changing a fan is a CORGI job as is opening the combustion chamber.

Tony

 

[al-yeti]

Yes agile i know that!


you seem to give good help sometimes and i want to stick to the water section, and i do stop at gas , never dealt with it and dont intend to either,


how am i supposed to know if the combustion chamber for example is not leaking out after i was to mess with it, as i dont have the euqipment y would i want to do it?

so give me some ideas, or someone else will i guess.