Wiring for 3 port valve

[kojakxx]

When fault finding for no CH or no HW or both on a Y-Plan system, how do you know when the 3 port valve or other components are at fault. The reason I'm asking is I've been taken off servicing to help with breakdowns with very little breakdown experience (we all started sometime) I have the honeywell guide but it doesnt show a flow chart or an idiots guide so if anyone can direct me to a webpage or post their own procedure it would help, I'm ok(ish) with a multimeter. Thank-you.

Searched and found: http://content.honeywell.com/uk/homes/FAQ/v4073aop.pdf
which is very helpful, but i'd like to know a check that other engineers would do, ie, check programmer first, room stat, cylinder stat then 3 port..or straight to 3 port etc.

 

[seco services]

depends what the customer tells me as to what i check first.

but useally i would start from the programmer - wall stat,cyl stat - valve - boiler/pump.

understanding wire colours and what they each supply helps alot and the basic workings of a valve.

 

[petit_pablo]

I start with what is working 1st. This can lead you along the right path.

For example if ch isnt working, flick on hw and see what happens. If boiler fires etc then that eliminates alot of the system. Put heating on, does valve move? If not, is room stat making and sending power to valve so on and so on. Its all fairly logical system faults just a process of elimination.

Learning sequences of operation for systems and boilers helps alot.