Y plan system problem. need help and advise

[rapid]

customer complaint they got central heating but got no hot water on a Y plan system. my 1st thought was diverter valve. when around to have a look, here's what happen-

turn thermostat up and then turn central heating on- boiler fires up and diverter valve moves to heating side.
while the central heating was ON i turned ON hot water, but diverter wasnt moving to the middle.
so i put central heating OFF, diverter valve still staying at the heating side and boiler back to stand by mode.
then i turned thermostat down to 10oC then diverter valve moves to the hot water side and boiler fires up.
turn heating back on and thermosat up diverter valve moves to the middle. i got hot water and central heating.

why wont the hot water come on while the central heating is on or the thermostat is above room temperature?

all components are connected to a Honeywell 42005748-001 Wiring Centre.
honeywell wireless thermostat
honeywell hot water cylinder thermosat
honeywell programmer
honeywell diverter valve

 

[Mike Jackson]

My first port of call would be to check the wiring but it may well be the circuit board in the 3 port playing up.

 

[rapid]

sorry mike i forgot to say, i have replaced a new diverter valve

 

[Simon F]

was the 3 port valve changed because of this problem, and has it made no difference?
or has the problem you mention only happened after changing the valve?
either way, trace the wires back to make sure everything is connected in the right place and responding as should be

 

[IND_Nick]

Hey rapid,

I have been to a few of these before and tend to find that they are wiring issues. Best thing to do is go back to the job and while on site call Honeywell with a multi meter to hand. The will talk you through the correct wiring and you can see if everything is where it should be. I think their helpline number is 0845 767 8999, but you can google it to check.
I would definitely check this before replacing anymore components.

 

[galaxy_plumbing]

you can download honeywell wiring guide on your mobile to help you if stuck

 

[rapid]

Hey rapid,

I have been to a few of these before and tend to find that they are wiring issues. Best thing to do is go back to the job and while on site call Honeywell with a multi meter to hand. The will talk you through the correct wiring and you can see if everything is where it should be. I think their helpline number is 0845 767 8999, but you can google it to check.
I would definitely check this before replacing anymore components.

Thats what i am thinking as well but they got this system installed last Oct 2011 and they said everything works fine so how could it be a wiring fault!

 

[BLOD]

Sound like a wiring issue to me.
Sometimes its easier to disconnect everything in the wiring centre and start from scratch

 

[mountainman]

Sound like a wiring issue to me.
Sometimes its easier to disconnect everything in the wiring centre and start from scratch

I agree, at least you will know that the wiring query can be eliminated should the fault persist.

 

[rapid]

i think i will call honeywell and find out whats what. Thanks for your replies.

 

[thedayjobs]

yeh, i think so,

you can download honeywell wiring guide on your mobile to help you if stuck


​

 

[rawr]

yeah once you get hold of a wiring diagram you'll be laughing, unless it doesn't solve the problem, but you'll still have a wiring diagram which is a plus

 

[RoryD]

Because the cylinder stat is in the equation due to this being a mid position valve. I would see what the reaction is when you adjust up and down(make / break). Have had problems similar to this before where the issue was the aforementioned cylinder stat

 

[Backboiler]

Have you fitted the new valve the correct way round?

 

[rapid]

Hello guys, here's the update. It was a faulty programmer- one of the relay has gone, so only one thing can be turned on at a time. when turn hot water or heating on you can hear a click on the programmer, but when you turn both on, the 1st one (e.g hot water on) will "click" and boiler fires up, then turn the second (e.g. central heating) one on it wont click. Replaced the honeywell st9400c programmer- everything works fine now.

 

[vern]

Hello guys, here's the update. It was a faulty programmer- one of the relay has gone, so only one thing can be turned on at a time. when turn hot water or heating on you can hear a click on the programmer, but when you turn both on, the 1st one (e.g hot water on) will "click" and boiler fires up, then turn the second (e.g. central heating) one on it wont click. Replaced the honeywell st9400c programmer- everything works fine now.

Was gonna say the timer from what you had said, sick of changing the ST9100 + ST9400 all around a year old, recall has been done, but there were too many already fitted!