Y plan wiring and how it works

[plumbow]

Hi, guys i resently i built my self a board using all the conponants to help me under stand how to fault find a y plan heating system, im having problems under standing three things and how they work, so i can finally get it work properly.

1)the perpuse of the off wire from the programmer to the wire centre.
2)The mid postion valve and how it works when each wire is powerd.
3)the cylinder stat what it powers and what its powerd.

Any help will be appreciated

Thanks

 

[gasmarc]

have a look at the honeywell site they also do a very good course , one thing I can guarantee is you never stop learning in this job

 

[clydey]

here is something i found from somewhere and you need a v4073a mid pos valve internal schematic to understand it,
3 port mid pos valve moves to 3 positions using only non reversable AC motor, a spring , a couple of microswitches 2 resitors and a diode and acts as a relay for the boiler. The spring pulls the valve to pos A, while the motor winds it towards pos B. If the motor is left continuously powered, it will stall in pos B , but if it is fed with DC (produced by resistor and diode) then it will stall in any position. Two microswitches operating just either side of the A+B port are used to define the position. The switches SW1 and SW2 are shown in the valve rest position (A) As the valve moves over towards the B position, SW1 changes over just before the A+B point and SW2 just after
note i will continue on next post as i wrote this before and it would not post and work was lost cheers

 

[clydey]

The white and grey wires are the control inputs,the orange is the output to the boiler. in the BOTH OFF STATE , the system wiring results in grey being live. If the valve happens to be in the A+B or B position , SW1 will have been operated , the motor will be fed with AC , and the valve will wind to pos B and stay there (although the orange boiler output will not be live). The 270k resistor supplies a small AC current to de-magnetise the motor from the effects of the rectified DC that is used to hold it in the MID-POSITION, without this there is some risk that the return spring will not be able to overcome the residual magnetism to return it to the END position
more to follow cheers

 

[dontknowitall]

Not much idea what you're on about but I guess I'll be reading this when I might look up Y plans on here as I've come across this type of language on quite a regular basis in the last few months or so.

 

[clydey]

In the HOT-WATER-ONlY state neither grey nor white are energised. The spring will therefore pull the valve back to A where it will sit.
In the HOT-WATER-AND- HEATING state , white is energised. If the valve is at A the motor will wind it until A+B, whereapon SW1 changes over, DC is applied to the motor via SW2 and it will stall. If it overshoots, or if is at B , SW2 will be operated as well, removing all power from the motor, and allowing the spring to pull the valve back to A+B. note - as the spring pulls the valve from B to A+B , the motor acquires quite a momentum and overshoots. It then winds forward a little and stops in the correct position.
In the HEATING-ONLY state both white and grey are energised (hence the need for a change over tank stat and a HOT WATER not required output from the programmer). Regardless of the position of either switch, AC will be supplied to the motor, and it will wind to position B. In addition, SW2 will connect white to orange, switching on the boiler. (the boiler is switched externally to the valve in the other situations).
hope this helps
this is not my own work
cheers

 

[dontknowitall]

I can see a click on the PRINT button coming up!

 

[markproperjob]

phone honeywell, and ask for a honeywell wiring guide.
its a heating engineers bible, all that spaghetti will make sense!!
very helpful people with SUPERB one day courses.
did mine years ago, and have requested replacement wiring books a few times!

 

[clydey]

definately do the honeywell course used to cost £50 quid with tea and bickies thrown in
cheers

 

[dontknowitall]

I've been earmarking this course for a while - trouble is I'm so busy at the moment and live miles away from any of the training locations.

 

[REDSAW]

wot weu cold du wit isa rally gud scumatic digrophagm on thiss foram su weall culd sea it.
eny on?.

 

[clydey]

this has diagram of the 3 port valve and also descriptions.
www.gasheating.co.uk/Mid-Position-Valve.html
hope this helps cheers

 

[stevetheplumber]

one thing to remember is the hot water stat is wired with power to the common terminal and sends power two ways depending on wether the cylinder is hot

 

[joe plumber]

best thing to do as has been mentioned is get one of those honeywell books thay are a godsend.i taught my self system wiring a while back using that book. the key thing to remember is that you basically sending a switch live from programmer to boiler. e.g. prgrammer, cylinder stat , 3 port, pump , boiler in that order. so if you get called to a fault you know roughly where to start looking e.g. is the pump running?/ etc. people seem to lose confidence with it as the open the wiring centre and just see a mess but if you picture the circuit from the honeywell book and think about what each component is trying to do its pretty logical.

 

[kirkgas]

i have a superb honeywell powerpoint that has all the systems on it which energises each wire per click and shows the power flowing to the controls and how they work, anyone who wants it send me a PM with an email address

 

[dontknowitall]

I spent yesterday morning trying to unravel a blown fuse when the programmer was turned on.

Not sure I need to go on this Honeywell course now as I can now use my multimeter properly, follow the wiring plan accurately, follow wires and changes of colours and things, etc, etc.

Once you get a clear head, it's kids play really!!

 

[tamz]

Here is a really good site to explain exactly how a Y and S plan works

Honeywell Y-Plan Explanation

 

[dontknowitall]

Hehe!! I like that one. Sick of that S plan diagram now after yesterday.

 

[mutley racers]

Hi Kirk gas, am sorry but i cannot seem to remember how to post a pm message. I have pm you before talking about the Acs exams and what practical assignments to expect. You said i should pm you as am about to start the acs course. You said you could send me some example papers that you use at your college. I started the 5 day course today and would really appreciate them now if they are still available. Also, i would really appreciate the honeywell powerpoint. Sorry to sound cheeky just asking for stuff. I just want to be fully prepared for the future. My email address is [email protected].

I look forward to hearing from you

Leroy

 

[buckley plumb]

if you join the grey and white wires the valve can be used as the old style diverter priority hw valve

ant

 

[fuzzy]

Hi, guys i resently i built my self a board using all the conponants to help me under stand how to fault find a y plan heating system, im having problems under standing three things and how they work, so i can finally get it work properly.

1)the perpuse of the off wire from the programmer to the wire centre.
2)The mid postion valve and how it works when each wire is powerd.
3)the cylinder stat what it powers and what its powerd.

Any help will be appreciated

Thanks

a y plan is simply a series of switches, like a light switch. the programmer is a switch, on and off but uses time clock to turn on and off. room and cylinder stat used temperature, but simply a switch.

mid position valve is a small ball which is either one way, the other or in the middle to allow water to each circuit
the 'off' wire is to power the motor to close the HW port when off. an s plan doesnt need one

 

[fuzzy]

The white and grey wires are the control inputs,the orange is the output to the boiler. in the BOTH OFF STATE , the system wiring results in grey being live. If the valve happens to be in the A+B or B position , SW1 will have been operated , the motor will be fed with AC , and the valve will wind to pos B and stay there (although the orange boiler output will not be live). The 270k resistor supplies a small AC current to de-magnetise the motor from the effects of the rectified DC that is used to hold it in the MID-POSITION, without this there is some risk that the return spring will not be able to overcome the residual magnetism to return it to the END position
more to follow cheers

orange isnt always the output wire, is also a signal wire