Vaillant diverter valve Improved design?

[jakeycrx85]

Also the CH and DHW worked perfectly for a day after I played around with it and is working perfectly again after a second fiddle. Correct me if I'm wrong but the CH and DHW wouldn't function correctly if the motor wasn't attached correctly.

 

[Bunnyman]

Could be the stepper motor playing up or poss pcb, these are very tempermental

 

[jakeycrx85]

Could be the stepper motor playing up or poss pcb, these are very tempermental

The motor looked to be winding in and out OK when I had it off. I guess it could be the PCB but the fact that mechanical intervention makes it start working again definitely points to the valve or motor.

The new diverter valve comes with a new different type motor so I'll see what happens when I fit it tomorrow. I've had 3 consecutive hot showers now but I'm just going to change it anyway.

 

[jakeycrx85]

I thought I'd give an update. I've changed the diverter valve and you'll all be very disappointed to know there was no spraying of water anywhere and I didn't even get wet in the slightest. I closed all the TRV's/valves and then cracked open the drain cock and left it for about half an hour.

There was a bit of a dribble when I pulled the diverter valve out of the pump but it just ran into the sump/catch tray and then I had to wedge a towel underneath the boiler as it soon starts leaking through the corners of the sump/catch tray.

I've bled the system and been running the CH and DHW continuously for the last couple of hours and all seems good. No leaks and the DHW temp is good. I am planning to get the boiler serviced in the near future as it overdue and I obviously want to make sure it is in a safe condition. Hopefully this will keep the RGI's happy although I'm not too sure.

The new valve is slightly different. It has a plastic valve seat for the hot water position where as the original type just uses the brass material of the valve as its valve seat.

Old valve

New valve

You can see the difference in the bodies of the 2 valves and where the plastic valve seat clips into the new valve.

I also changed the AAV as the old one had been leaking fluid out of the vent. It was really crusty. I'm guessing all the crap and gunk in there was limiting the floats travel and allowing fluid out when it shouldn't have.

 

[Bunnyman]

Nice one that plumbing is an absolute disgrace, and why do you have your hose connected to the mains hot out???? No need to touch that or turn the water off, no disrespect (but you did have a dig about how easy our job was compared to what you did) you said your a highly qualified engineer i would have thiught a cursury look at the schematic of the unit would have shown that?

 

[jakeycrx85]

Nice one that plumbing is an absolute disgrace, and why do you have your hose connected to the mains hot out???? No need to touch that or turn the water off, no disrespect (but you did have a dig about how easy our job was compared to what you did) you said your a highly qualified engineer i would have thiught a cursury look at the schematic of the unit would have shown that?

It's not connected to the DHW. It's just the straight on angle of the picture making it look that way. It's connected to the 22mm CH pipe.

There is no drain cock on the hot water pipe. The only drain cock is on the CH pipe

 

[jakeycrx85]

If I had drained the DHW instead of the CH I would of got very wet!

I didn't turn the water off either.

 

[Phill Peck]

It's quite normal to get the volume of the expansion vessel empty it's self when u pull the diverter out.
Shame that didn't happen

All sorts now anyway........

 

[jakeycrx85]

It's quite normal to get the volume of the expansion vessel empty it's self when u pull the diverter out.
Shame that didn't happen

All sorts now anyway........

How does the PV retain water? Surely it just drains out whilst you're draining the system down?

Or does it only retain water if it's not properly pressurised? Does the diaphragm fully expand to the whole volume of the PV when you drain the system when fully pressurised?

 

[Phill Peck]

Because there's only 1 connection it creates a vacuum.
I always depressurise EV first then drain then recharge which pushes the rest of the water out.

 

[jakeycrx85]

Surely recharging it is only going to take it back to it's original position though if it's at the correct pressure to start with so how does that push more water out?

I only recharged mine last week. I pressurised it to the Vaillant maximum recommended pressure of 0.9 bar. I'm guessing the diaphragm must completely displace the whole volume of water in the PV when correctly pressurised hence why I didn't get any major flow of water.

 

[Steelmasons]

Surely recharging it is only going to take it back to it's original position though if it's at the correct pressure to start with so how does that push more water out?

I only recharged mine last week. I pressurised it to the Vaillant maximum recommended pressure of 0.9 bar. I'm guessing the diaphragm must completely displace the whole volume of water in the PV when correctly pressurised hence why I didn't get any major flow of water.

....jeez...you obviously haven't a clue , I'll guarantee you'll get nothing but problems since you've meddled with it.
So 0.9 bar pre-charge pressure to vessel , what have you set system cold fill pressure to??.....

 

[jakeycrx85]

Surely recharging it is only going to take it back to it's original position though if it's at the correct pressure to start with so how does that push more water out?

I only recharged mine last week. I pressurised it to the Vaillant maximum recommended pressure of 0.9 bar. I'm guessing the diaphragm must completely displace the whole volume of water in the PV when correctly pressurised hence why I didn't get any major flow of water.

....jeez...you obviously haven't a clue , I'll guarantee you'll get nothing but problems since you've meddled with it.

Please explain how it works then

Why am I going to have problems? What would you have done differently?

 

[AGAS]

YOU WAS WARNED

sounds like you are always fiddling with your boiler . hope you tell the service engineer what you have done ( i don't think you will )

 

[Steelmasons]

What would you have done differently?

So you are asking for advise on how to replace a part on an appliance you shouldn't be working on?
I was talking to the local gardener today when he told me he replaced a monobloc mixer tap this morning , he also told me the water has been left off due to him cross threading the flexi hose to which he will try and "sort out" next week some time...
So the customer is without water @ kitchen sink until "some time next week"......
It just about sums up you DIYers.