ALPHA CB28X Diverter Problem

[edgardavids]

Hello All

Sorry for the long post but here goes

I have read loads of topics on here about the problems with the diverter valve on this model...... DHW flow switches, Diaphragms and the Valves themselves...........

My symptoms are similar to some in as much as Heating is fine but no DHW unless the heating is on ????

Checked the switch first, click,click click on and off about 50 times in order to prove it worked everytime and it did, Next i bought the diaphragm repair kit with all the new seals (Looked like mine had been leaking for quite some time just above the DHW side of the valve where it unions onto the HEX) After lots of wrangling (small corroded screws!!!!!!) got the valve out and the Diaphragm looked pretty tired and had a tear, I replaced it and put it all back together BUT still no DHW unless the heating is on............ So is the valve itself knackered for reasons stated below ???

I removed the switch and rigged up a small mirror so i could see if the spindle was moving in and out when the hot tap was opened ? I only see one spindle so don't know if that is correct and it moves from left to right ie in towards the DHW housing as the tap is switched on and back when it's switched off but not quite far enough in order to let the switch drop and switch the hot water on Should another spindle from the diverter end follow up behind this ?

Secondly I know these have a reputation to leak when all put back together and mine is no different, I have 2 small leaks on 2 of the unions where is connected to the underside of the HEX. I was careful to clean the surfaces and fitted new seals but they are still weeping........Any tips to stop these ?


Many Thanks
ED

 

[plumbplumb]

Did you check all the housing where the diaphragm sits and the filter is clear?

Usually if it's the fiber washer leaking a bit of compound (boss white) should sort it or replace the washer with a thicker fiber washer I've had them leak and faffed about for a bit and end up slinging the new washer and putting a new one in.

Ferolli (despite being a crap boiler) does do a good quality washer kit for the Modena

 

[edgardavids]

The housing was clean as a whistle and the little white plastic piece (filter ? ) in the bottom of the housing was also clear. I'm getting good water flow from my hot taps albeit its cold water coming through so don't think there is a blockage.

I have found a good coloured picture on this thread and some excellent advice //www.diynot.com/forums/viewtopic.php?t=79989&start=15

Paul Barker (Alpha specialist) goes into good detail about how the diverter actually works...........

When water runs through mine the pin pulls back but not far enough to allow the switch to operate and also the pin from the other side is not following it across as i believe is supposed to happen ? . This side of the DV seems more fidly and i'm wondering if replacing the whole valve is going to be the sensible option ?

Any more thoughts

Cheers ED

 

[edgardavids]

Just an update...........

Diverter valve replaced at the weekend and we have lovely hot water

Thanks to all the good advice on this site my problem see to be sorted fingers crossed !

Thanks again

ED