Could anyone recommend a reasonably basic but comprehensive technical reference book on domestic / light commercial heating systems, especially piped wet systems?

Lyle,
I believe that Newnes have a Reference book written for Heating systems.
And like the rest of the Newnes texts, they ARE comprehensive!.
But, if you can't find what you are looking for, email me, I have a few books on this myself!.

Thanks for the offer Trumpy. Actually, I spent most of my working life involve in Building services, including wet system heating. I really want access to a modern reference text for my students who are on an electrical building services course. Any texts that I have reviewed tend to be a little too involved, certainly any of the texts in my own keep are too heavy on the maths! I guess that I am looking for a text which you can read in the loo!

Lyle,
Yes, I certainly know what you mean there!.
There are a lot of subjects that could do with being explained in plain English.
Unfortunately, textbook writers tend to get bogged down in technical jargon and maths and this makes it hard going for people like you and I, why cant they just explain things in simple terms?.