Christian McArdle wrote:
Two valve to go wrong. With a combi, there is no wiring.

Yes, two valves, each costing 30 quid, rather than a 3 port valve
modified just enough by the combi manufacturer for the express
purpose of being able to charge 150 quid for it.

Christian.

Make that two _easily accesible_ valves, in most cases.

Apart from leaving myself gasping on the floor due to not turning off the
mains before putting some tape round the connector block, fixing a broken 2
port valve motor was a breeze.

Bob