Boiler not switching off

[silvatray]

Hello

I am wondering if anybody has come across the following situation that is occurring with my boiler and can give me a heads up on the situation, so that I can have a clearer understanding to resolve the issue somehow with my installer.

Two years a go I had my old Servowarm Boiler replaced with a Worcester Bosch Greenstar 24i System Boiler, Drayton RTS Thermostat, Drayton LP522 Program Controller, Drayton MA1 three port valve and Bulldog TRV’s on the necessary radiators which were also flushed out.

The system normally works fine with CH and HW coming on both together in the morning and evening with the HW turning off before the CH.

The problem occurs if we say make a demand on the system outside of the program times i.e. override the programmer / advance. The system appears to stay turned on making a demand to the boiler even when both of the LED’s on the programmer show that that the boiler should be off.

Originally my installer wondered if the three port valve had been sticking open and so came back and replaced the actuator head on the three-port valve and also the Drayton LP522 programmer for good measure but this did not resolve the issue.

I appear to have isolated the issue to the HW side of things, it appears that when we advance on the HW this causes the fault to occur (or if HW comes on and the CH has been advanced to turn the heating on now it’s colder). The problem is resolved by simply turning the HW off and this sorts out the problem on the boiler turning the system off.

I spoke to Worcester Bosch who said they did not feel it was an issue with the boiler but a voltage might be running back from the controller valve to the boiler which required tracing. I know at the time that when my installer came round to replace the three port valve there was mention of a “rouge 210V feed going” around which might be causing the fault (I am recalling the last bit about the 210v from memory so that might not be the correct voltage).

I’m just wondering what anyone’s opinion is and whether there is an issue with the wiring to the controller / electrics in general.

Untitled

• silvatray
• 20 Dec 2009
• 1

Untitled

• silvatray
• 20 Dec 2009
• 1

 

[picasso]

you need to post a wiring diagram, the pictures dont tell us much.

 

[adlplumbing]

looking at my jtl wiring plan for y system no it does not look right get some one with part p or 17 edetion to have proper look maybe on electircs forum

 

[DP]

Wiring diagram is not to standard format. Starting from left, it would normally be live, neutral, earth, CH from programmer to roomstat, from roomstat connected to white of 3 port etc.

adlplumbing, sparks are good with house wiring (soon will be making tracks to my bunker to escape electrical missiles) but only some know their way around controls. To wire CH controls, one has to be electrically savey as well as be a heating man to tie two loose ends together. Have been to many installations wired very well but system does not work too well.

An example of above is a house where I fitted a Baxi 105e boiler with two zones. An extention was planned and build several months later that was to have UF heating. The spark had applied 240 volts to orange with other wire (grey) to 4 to run the boiler. Two original MVs applied zero volt s/c across 3 and 4 but new valve from UF was now not voltage free. Isolating the boiler from front panel ON/ OFF switch made the boiler live all the way to neutral as far as the NO/ OFF switch

 

[silvatray]

Sorry Picasso

By wiring diagram do you mean the diagrams from the install wiring guide – I have taken pictures of them and also flipped the image of the junction box the correct way up as you see it

As you look at the wiring the box is numbered 12 to 1 with position 12 being at the top of the box and position 1 at the bottom. The left hand side of the wiring appears to deal with the Three port valve / Boiler Stat/ and Programmer whilst the right hand side appears to deal with the feed to the thermostat and the mains electricity (but this is strictly a laymans point of view).

I have done my best to jot down the positions and wires attached, not being a sparks I have referred to the colour of the wires as on a plug so Live is brown etc



Position 12 Left - Earth (3 Port V) Right - Earth x2
Position 11 Left - Live (Prog) Right -Live
Position 10 Left - Neutral (Prog) / Neutral (3 Port V) Right - Neutral
Posiiton 9 Left - Empty Right - Empty
Position 8 Left - Live (3 Port V) / Neutral Boiler stat Right - Live
Position 7 Left - Grey (Timer) Right - Live
Position 6 Left - Black (3 Port V) Right -Grey
Position 5 Left - Black (3 Port V) / Earth (Boiler Stat) / Earth (Timer) Right - Empty
Position 4 Left - Black (Timer) / Live (Boiler Stat) Right - Empty
Position 3 Empty both sides
Position 2 Left - Empty Right -Neutral
Position 1 Empty both sides

[/b]

Untitled

• silvatray
• 20 Dec 2009
• 1

Untitled

• silvatray
• 20 Dec 2009
• 1

Untitled

• silvatray
• 20 Dec 2009
• 1

 

[D_Hailsham]

Remove the LP522 from the backplate and make sure the switch/link on the back is in the P (pumped) position.

Position 12 Left - Earth (3 Port V) Right - Earth x2
Position 11 Left - Live (Prog) Right -Live
Position 10 Left - Neutral (Prog) / Neutral (3 Port V) Right - Neutral
Position 9 Left - Empty Right - Empty
Position 8 Left - Live (3 Port V) / Neutral Boiler stat Right - Live
Position 7 Left - Grey (Timer) Right - Live
Position 6 Left - Black (3 Port V) Right -Grey
Position 5 Left - Black (3 Port V) / Earth (Boiler Stat) / Earth (Timer) Right - Empty
Position 4 Left - Black (Timer) / Live (Boiler Stat) Right - Empty
Position 3 Empty both sides
Position 2 Left - Empty Right -Neutral
Position 1 Empty both sides

Unfortunately colours mean nothing when it comes to wiring up heating systems. Blue and Green/Yellow wires are often used as live conductors.

There is no mention of the Grey, Orange and White wires from the motorized valve.

Which are the room thermostat and cylinder thermostat?

We really need to know what device each wire connects to including terminal number on the device.

 

[picasso]

you have a "nuetral " on its own, so the wiring is all over the place, in this case I would disconnect all the cables, trace them and start afresh following a y plan diagram.

 

[silvatray]

thanks picasso / adlplumbing / DP I'm not a sparks so I would not go anywhere near this, when the guy who installed it checked everything he said it was OK so I wouldn toknow to differ but from what you are saying all is not well.

 

[silvatray]

D Hailsham

I asked about the switch on the back of the LP522 and I am assured that its set in the P position. I really dont have a clue where the electrics are concerned what I have marked down is that the room thermostat must come from the right hand side based upon how the wires are chased into the wall, whilst for the cylinder stat I have referred to this in the diagram as "Boiler Stat".

appreciate you looking / replying - the spakr sis meant to be cmoing back which is why I thought I would rasie the issue to try and have a clearer understanding as it appears to be the electrics which are causing the fault

 

[D_Hailsham]

the sparks is meant to be coming back which is why I thought I would raise the issue to try and have a clearer understanding as it appears to be the electrics which are causing the fault

Ask the sparks to provide you with a diagram/list stating what each wire does. Then if it still does not work, you can post his info and we can analyse it for errors. (But don't tell him the last bit. )

 

[keego]

I had a similar situation a while back with my own 24Ri but with the boiler not turning off straight when the demand finished on CH, although if you left it alone it would eventually switch off when the boiler reached temp.
It turned out that when the demand finished on CH there is a small voltage (69v) on the orange wire from the 3 port, this is not present when the demand finishes on HW. This voltage is enough to keep the board from shutting off the boiler & fitting a capacitor between the orange wire & the neutral will get rid of this stray voltage.
You seem to have the same situation although in reverse which makes me wonder if your 3 port is on the right way around? it will be marked up A & B with the B port going to the cylinder.

 

[adlplumbing]

dp yes i will agree with you some sparks don`t know way round heating system but let face neither do some plumbers
like me i will re wire individual compents but not the whole lot as i will make a mess saving up for part p to help me get better on this other wise i am study books till then

 

[picasso]

part p wont help you with central heating wiring, honeywell do a course thats pretty good but generally its down to reading and practise.