Turbomax 242e diverter

[carver1]

Hi there I have the above boiler and it seems the diverter is faulty, in as much as the valve seems to settle in mid position, so that hot water never gets a chance to circulate round the central heating as most of the water is circulating round the easier path of the heat exchanger for hot water.
Therefore boiler comes on for heating, flow pipe heats up quickly but only in the first foot or so at the same time the heat exchanger heats up, and the boiler cuts off thinking the heating has reached temperature, when the return pipe remains stone cold.
Running hot water moves the white lever to activate the microswitch but that lever never rests at the top as it should..
I have just replaced the diaphram along with the two o ring seals and it is exactly the same

I know there is an upper kit available but cannot see how this is preventing the torbek style diaphram valve from working properly? I also checked there were no blocked holes or anything fouling the lower section.

Can someone please suggest where the problem might lie??

 

[carver1]

Thinking on, could it be the spring in the upper section gone weak or even broken?? I noticed when pushing the diaphragm plate it was relatively easy to push at first but then the pressure significantly increased to activate the switch...

I am only asking because I would rather not pull it all apart again without having a better idea as to what could be going on!

 

[Gasguru]

IMHO it's become a waste of time refurbing these diverters...change the whole thing and even then don't expect it to last more than a couple of years.

I used to get away with just refurbing the lower section but if the upper section is sluggish it's best to change the complete valve.

Vaillant parts quality has dropped considerably over the years.

 

[carver1]

Thanks Gasguru I decided to pull the thing apart one more time to try to work out what might be going on.. Decided to look in the lower section again and would you believe I found a bit of grit in a small venturi type bypass leading to the heat exchanger! it was the only hole I couldn't blow down but for that reason I should have tried poking it I guess!

All sorted now

 

[Gasguru]

Use long nose pliers and you can just pull out the venturi to clean it properly. However, even when the lower section is spotless and with a new diaphragm the top section is often too sluggish to allow the microswitch to operate.