Y-Plan heating and "Last Port of Call" issue with 3-port valve

[Johntheo5]

John, what is the source of this information.

Mainly from this link, (John Ward), I think this de magnetizing AC current is actually applied in both the mid position & the CH only position?.

Another interesting link.

https://electrical-engineering-portal.com/methods-braking-motor

 

[Exedon]

Long since swapped on to using E P H motorised valves/controls
Decent price and 5 year warranty rather than the 12 months offered by honeywell drayton danfoss ect.
Having said that never yet changed a E P H zone valve

 

[Johntheo5]

That extra relay hack is really very clever and something I might now do. Is this something that could theoretically be done or do many add this to their Y Plan in practice?

A old (very) electrican friend of mine did this many years ago, he has passed away but the 3 port is still the original.

 

[ericmark]

The Y plan was favoured as it allowed the boiler to cool by heating the DHW when boilers did not have a cool down option. As soon as DHW is required and not CH the valve will return to rest, and there seems in the main little point in turning off DHW.

However the solar panel has altered the situation, during the summer there is no longer any point using gas/oil/solid fuel to heat the DHW when there is a load of free solar power available.

Much depends on the tank thermostats settings, in the old days the immersion thermostat would be set lower than the boiler thermostat so while boiler is running it takes priority, but this is reversed where solar is used, the boiler thermostat is set low, so the solar takes priority.

On the other hand, adding more complexity to what many find difficult plan to wire
While y plan is not difficult to wire up, look at the queries, you would think it is rocket science

This is a problem, when I employed a heating engineer, not plumber or electrician but some one who should understand both sides, he was unable to work out what my relays did on my C Plan. For some reason, not a clue why, I have two pumps, one drawing from flat, the other drawing from main house. With both running no problem, but with only one running it would reverse flow in the other circuit. Why set up this way I have no clue.

My first idea was a non return valve, but advised this will not work very well when the pump is on return, so second idea was motorised valves, but the valves only have one micro switch, I need two, one to work boiler the other to work the pump. So fitted a relay, so I do have two sets of contacts, did not seem rocket science, but the heating guy could not work it out.

As to why two pumps, not a clue, it was like that when I bought the house, and why on return not a clue, but I do wish I could turn DHW off, but alas no, so if I need CH then water also heated.

 

[DP]

As to why two pumps, not a clue, it was like that when I bought the house, and why on return not a clue, but I do wish I could turn DHW off, but alas no, so if I need CH then water also heated.

Again not rocket science.