Diagnosing CH controller/valve problem - quick sanity check

David · 2018-12-30T09:59:01+00:00

As discussed previously I suspect I have a fault in the 3 port valve. Drayton Mid Position Actuator MA1.For diagnostics, do I have to do more that check that when CH is called for by the programmer power goes to the thermostat, and when the thermostat clicks on power comes back to the valve?I am assuming that the sequence at the valve is:(1) CH request from the thermostat(2) Mid port valve moves to open CH port(3) Controller then calls for pump and boilerThis has the second assumption that if (2) fails to happen then (3) will not happen (which seems to be more or less what is happening).Diagnostics day tomorrow, hopefully.CheersDave R

Dec 30, 2018 Last reply: 7 years ago 20 Replies

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Roger Mills 7 years ago

Well, all 3-port valves are the spawn of the devil. Far better to convert to an S-Plan system with 2-port valves and with totally independent control of HW and CH.

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