Diverter valve v motorised valve

[jubbly]

Hi again - not sure if my earlier post actually made it, so here it is again. I have a Viessmann Vitoden 200 boiler, fitted in the garage using the four pipe system. This is our 3rd boiler in 5 years, the problems with the other two (Vitoden 100) being the diverter valve in the boiler kept getting stuck and hot water was being pumped around the CH when boiler calling for HW and we often came home to an absolutely stiflingly hot bungalow. Viessmann very good and kept coming to sort it out, but I'm getting stressed that the same problem will happen again. We have a motorised valve in the loft alongside our unvented cylinder and I was wondering whether having two diverter valves could in some way have caused our previous problems - doesn't is confuse the system? Surely with the four pipe system there is no need to have this motorised valve as the diverter valve in the boiler is sufficient to direct the water either to HW or CH. Also, now and again, we hear a clonk when the pump stops running, which used to happen with the other boilers and then the problems started. As you can see, I really am getting stressed that we're going to have the same problem again and again. Surely 3 boilers can't be faulty. Any help or advice greatly appreciated. Jubbly

 

[libby lou lou]

thatshardtoread

 

[stardanny]

We have a motorised valve in the loft alongside our unvented cylinder and I was wondering whether having two diverter valves could in some way have caused our previous problems - doesn't is confuse the system? Surely with the four pipe system there is no need to have this motorised valve as the diverter valve in the boiler is sufficient to direct the water either to HW or CH.

Hi.
I may be wrong but that motorised valve is part of unvented cylinder in it kit form and normally be open, part of safety system. If the cylinder overheat by the boiler, limit stat will cut in, power up the motorised valve to closed it, stopping heat going to cylinder.

Other may have answer...

Dan

 

[jubbly]

We have a motorised valve in the loft alongside our unvented cylinder and I was wondering whether having two diverter valves could in some way have caused our previous problems - doesn't is confuse the system? Surely with the four pipe system there is no need to have this motorised valve as the diverter valve in the boiler is sufficient to direct the water either to HW or CH.

Hi.
I may be wrong but that motorised valve is part of unvented cylinder in it kit form and normally be open, part of safety system. If the cylinder overheat by the boiler, limit stat will cut in, power up the motorised valve to closed it, stopping heat going to cylinder.

Other may have answer...

Dan

Hi Dan - many thanks for your prompt reply and yes, you're right, the valve did come with the kit, but I was hoping you'd say it could be taken out. Perhaps not though - wouldn't want my cyliner to go into orbit!