Help with location of valve on gravity fed HW system

Better_Days

I have an elderly oil boiler which has gravity fed HW and pumped CH. (Photos below of pipework) I found this really useful pdf with some helpful diagrams, my sytem looks like the diagram on p5 (although I don't know if we have 2 tanks in the loft)

www.heating-and-plumbing-solutions.com/AddCont.pdf (if you click the link the pdf should download)

I would like more control over the HW as it gets very hot in the winter when we turn the boiler up.

There are 4 pipes coming from the boiler and it appears that the CH and HW are separate loops. Down the side of the boiler there are 2 big pipes, 2 medium pipes, and 2 small pipes (for the HW, CH and ?)

From the reading I have done it seems that a 2 way 28mm valve could be fitted to either the flow or return pipes to/from the HW cylinder. However, do I understand correctly that the valve must be fitted between the cylinder and the pipes going up to (I assume) the tank in the loft, presumably so as not to disrupt the gravity system?

If I have understood all this correctly is there enough space with this layout of pipework or have I misunderstood the layout?

Also, and apologies if it is a really daft question, but does the valve need to be connected up to a tank stat, which in turn needs to be connected to the programmer? Thanks

Pipes at bottom of the HW tank in airing cupboard:


Pipe at middle of the HW tank (also is a pipe coming out of the top of the tank - for HW to taps?)



Pipes at side of boiler (downstairs below airing cupboard):


Pump

squeekswhenwalking

Unfortunately as your hot water is gravity it also has the vent off it, just fitting a valve a) won't work and b) could be potentially dangerous if the vent is restricted. To achieve what you want the system could be converted to a fully pumped system, but not recommended as a DIY job

Better_Days

squeekswhenwalking wrote: »

Unfortunately as your hot water is gravity it also has the vent off it, just fitting a valve a) won't work and b) could be potentially dangerous if the vent is restricted. To achieve what you want the system could be converted to a fully pumped system, but not recommended as a DIY job

Thanks squeekswhenwalking, just wanted an idea of what the possibilities are. The info I found suggested that if the valve was fitted before the 'T' to the vent it would be OK, but I wanted to check before I got a plumber/heating engineer in.

Is converting the HW to fully pumped a big job?