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Theorysparky

Domestic Electrician
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Problem i have is that when the hot water is on i don't get 240v at the room stat when i select heating (only 90v)

if i select heating first then hot water it has 240v and both work

this will only work when the programmer is set to 'allday' on both

if it is set for 'Auto' it does what it wants

when they are on individually the wiring tests out ok

when they are both on its the same

any ideas ???

i thought it maybe the programmer,,, i should have linked it out across the terminals and this would have confirmed it

Cheers Mark

 
Is the programmer mechanical or electronic?

We still have a mechanical programmer (Randall 4033) that is 25+ years old!!!!

To prove the programmer if wired as per Honeywell number scheme it would be terminals..

4:=Heat ON

6:=Water ON

7:=Water OFF

at the control J-box

Either strap some lives across terminals as appropriate to test each condition..

or Diss wires from programmer & meter out voltages coming OUT of programmer contacts..

Other thoughts..

How old is the three port valve??

Could there be something dodgy on the internals with the motor stall circuit?

 
Specs

the programmer is 12 months old and so is the 3 port valve

valve has been tested and is ok

i reterminated all the wires in the wiring centre last year ,,checked them again yesterday.

i think i will

'Diss wires from programmer & meter out voltages coming OUT of programmer contacts..'

then it will prove the programmer either way

Cheers

 
90v sounds like some sort of feed back. did the old clock switch from hot water to hot water and heating?might be why your getting both outputs switched when you turn on HW. hope this helps. i did one a few weeks back, chnaged a 1970's super switch (???) to a boss 7 day programmer just had to remember the heating on switched the HW too, which isnt a problem on this job, might as well get a tank of water while the boiler fires, where as when the HW only was switched on it just opened the HW valve and the boiler just fired to fill the tank.

---------- Post Auto-Merged at 23:27 ---------- Previous post was made at 23:25 ----------

oh just seen yplan.... doooohhhhhhhhh!

 
how have you tested the valve?

have you checked the voltages on the cables in each position?

oh, and how are you actually measuring this 90v? could it be phantom/induced? are you using a normal multitester?

 
the valve was new

thinking its phantom

customer wants the whole lot rewired now

wireless room stat hipee

i think its the room stat thats causing the problem and the asian family not knowing how to operate the programmer

 
Hello

just read your thread, I too have the Y plan and a randall 4033 programmer and had a similiar experience a few years ago. When I decided to change my old cast iron boiler ( big mistake) for a condensing boiler I chose a glow worm 18Hxi. I rang Glow worm and they assured me it would work fine on the Y plan.

After changing over the boiler and commissioning, all seemed fine. All controls and 3 port valve worked as per settings on programme. Except the boiler would fire on calling for heat when turning up the room stat but would not switch off when turning room stat down, I know it has pump over run, but just kept running.

Only way to stop was to turn off the isolation switch then turn back on. Checked all wiring no problem but found at the wiring centre I was getting a back feed of 115 volts from the boiler. Rang Glow worm didnt want to know and got fobbed off. I then rang honeywell but did not say the make of boiler. Honeywell replied "is it a glow worm because they do have a problem but are in denial and blaming our controls". Solution was to fit a 4 microfarad 240 volt capacitor across the live and neutral feed into the boiler, bought one from maplin electronics one pound fifty pence and fitted and boiler has worked fine as it should. So any feedback back a from modern boiler is probably the electronic circuits.

 
Thank you mmeech,

Welcome to the forum. Congrats on your first post. Don't leave it so long to post next time. Join in the banter with us. :D

 
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