Hot Water but no heating!

[Weg]

Hi folks, I'm new here so be gentle!

I have a Vaillant (either a VCW GB 242 EH or 282 EH / or EB - no model number on the boiler) I don't know how old it is, we moved into the property a year ago.

We had it serviced at the beginning of December because it was losing water pressure, its been fine since then - until yesterday.

As the header says, we can get hot water but there is no heating. I have noticed the water pressure has dropped but its not all the way down to 0. The temperature guage has bottomed out though.

Is this something obvious and simple I can fix or should I be calling out an engineer?

Any advice would be much appreciated!

Thanks

 

[ChrisR]

Probably to do with the diverter valve, the bit on the right which moves in and out when you call for CH or HW. Might just be loose microswitches but I think (I'm no expert) it's more likely to be something inside, or the Servo valve at the front which tells the DV where to go.