Help Re Boiler Actuator

[juco12]

Baxi Combi 100 HE plus.
Hot tap water but no heating. Checked water pressure etc and pump appears to be running when hot tap is run.

I suspect the actuator valve is faulty it is a Honeywell VC4012 actuator.

How can I confirm this, and is it an easy DIY fix.

 

 

[Andy™]

diverters are usually set to CH then moves to DHW as required, so unlikely to be that. if it was stuck on DHW then turning heating on would shut down boiler on overheat very quickly

when you switch the heating on, what exactly happens? any lights come on to say heating is on or any fault? you have switched the CH on correctly, havent you? usually needs both power selector set to CH & DHW, and any timers / thermostats switched on

 

[juco12]

Stat and power on ok. Selector set for both water and heating (winter mode)

Lights:

Power light on

When boiler fires giving hot water then burner light and hot water light on.

No warning lights on.

History...went on hols for 3 weeks and just switched off CH at the power supply socket, when I returned I simply switched this back on and the heating worked, 24 hours later noticed house cold, no heating, but tap water heats ok.

 

[New Venture!]

What style of timer does your boiler have? Analogue clock or digital display?

 

[juco12]

The stat is also the timer, digital hard wired (not wireless) Digistat 3

The stat is calling for heat.

 

[ProDave]

Is the pump running when you turn the heating on?

 

[New Venture!]

Sorry to ask the obvious, but is the small flame CH indicator showing?

 

[juco12]

Pro Dave.....Yes the pump appears to be running ok.

New Venture....The flame indicator comes on when the hot water tap is turned on.

 

[Sharpend]

Have we considered turning the stat up?

Alternatively gave you tried resetting the star/programmer?

 

[New Venture!]

I've installed a couple of these units, and if memory serves me correctly the small flame icon should show when the Drayton is asking for central heating.

Try setting the Drayton to manual (< button) and increase the temperature setting using the + button to around 27 degrees.

 

[juco12]

I will have a look at the settings tomorrow and report back, although the stat is calling for heat.

 

[juco12]

New Venture I couldnt find a manual setting, I played around with the stat/temp and still not heating the rads.

 

[New Venture!]

Do you have a Digistat +3? Have a look here to see if it's this one.

http://www.draytoncontrols.co.uk/WorkArea/DownloadAsset.aspx?id=10384

There should be a little arrow indicator in the display window that points to the operating mode.

 

[juco12]

It is the digistat 3 not +3, they are slightly different.

I did try setting at on all day and raising the temp but no change.

 

[Sharpend]

Have you access to actuator valve? Could try a gentle but sharp tap to see if it will free if you think it is stuck?

 

[juco12]

I have some access, are you talking the metal part that has the 3 pipes or the actuator being the part that connects to the 3 way valve. (excuse my terminology)

 

[Rob_the_rich]

I think the timer should be linked out, just to make sure that is not at fault.

Do you feel able to do this safely?

See section 8.8 of the installation manual https://www.dhsspares.co.uk/userfiles/Boiler_Manuals/BAX195.pdf page 27.

 

[juco12]

I would be ok doing that BUT I have an electrician mate who is going to try and come around tomorrow night so will let him do the necessary.  He has had some gas boiler experience so hopefully he can diagnose before I decide to get a fitter in.

I will now leave until tomorrow evening but will post back if we find the fault and let you know.  Thanks for the input.

 

[juco12]

Ok electrician friend checked a few things out but needs other testing equipment so hopefully tomorrow (Wed). Yesterday I had tried to get the actuator off to no avail and the elec also failed to get it off, but trying again later tonight I managed to find the well hidden button that releases it.   Will keep you posted.