water priority help needed

[Gangley]

I have a very old Mexico Ideal super 100 RS wired on a fudged Y plan and 2 motorised valves fully pumped system. When the C/H is running the hot water does not heat up. Is there any way to give priority to the hot water?

 

[ChrisR]

SUre - you need a 2 port motorised valve head with the "normally closed" contact on the microswitch connected, on the hw. The replacement (6 wire) heads usually have it, or you could solder one on, at a pinch.
Use that on a HW valve, to only enable CH if HW valve is not open.

Or implement W plan on the 3 port, though W plan isn't what most people would think of as "simple" HW priority.

If it's fudged etc, show us some diagrams/pictures.

 

[Gangley]

Hi Chris, Both motorised valves are six wire. I am not sure how the system has been fudged and probably not smart enough to understand how it has been bastardised. I would not attempt to rewire it for sure but the last guy who did was a guru and thought it ok to stick with.

All I can say is that, turning the demand for CH off allows the HW to heat up. I currently use the programmable room stat to run the CH, and the boiler programmer is on 24/7 for CH. I am about to put off periods in to allow HW to have a chance in them. Unfortunately this over-rides the "Extra Hour" facillity which does not work if the CH is on.
Tricky but workable for a man! However........