Strange fault with Drayton programmer

JD6400 · May 2, 2012

You have not got quite the same faults as what was probably the most annoying problematic job i have ever had since becoming a sparks but this may help ?
It was a boderous boiler (complete and utter useless unhelpful ----ers on their technical side !) run with Honeywell 2 and 3 ports along with a Drayton 2 channel controller .
The problem on this one was every so often the heating would just run on , no matter what you did at the controller and stat .
From memory it it would happen if both heating and hot water were selected and if the hot water became satisfied before the heating then the heating would never stop no matter what you did to it .
I honestly stripped the complete control circuit and re connected it from scratch over 12 twelve time on 8 different visits , it was made worse by the fact it had all come about because they had just had thermal solar installed with the new boiler a controller and valves so this made me question what we had done , so many times ( along with the inept moron at boderous ) !
I eventually called honeywell technical , who instantly said that it was a bit of a design fault on only certain boilers that will allow them to fire up on stray voltage and not just the 230v switch live that you would expect they needed to do it , the remedy was to put a little ( i think ) capacitor between Live feed in and sw live out on the zone valve as they never truly shut down and can allow around 30v through even when idle , if configured in a certain order !
The Honeywell technical chap even sent several photo copy's of the wiring diagram on how to do it and a handful of capacitor's for free !!!
Maybe worth a phone call to them if you have honeywell valves ?!

sedgy34 · May 2, 2012

Heating is the easiest thing in the world

merlinradioltd · May 2, 2012

truckster said:
Just a thought ...is the back plate fixed flat, the plastic plates can and do flex causing connection problems and it always seems to be the heating side.

Yes this has been an ongoing issue!...BG fitted a wall plate, but the wall is tiled. There was not enough tile behind the wall plate to screw the plate flat and solid to the wall...hence the 1st bodge they did with cardboard packing (from the box the controller came in!)....which fell out as the wallplate moved easily when attached to the programmer. Bodge 2 was where they were supposed to fit a proper back box (Drayton accessory) to fit the wallplate to the tiles and came to do it and forgot the part....BUT they had an old patress box in the van......which they sawed up to get two bits of plastic to act as spreaders across the gap in the tile..to get the wallplate to sit in such a manner as to connect "properly" to the controller......(you could not make this stuff up!!!!.)......I have never seen the likes if this before....At the moment it is working as I have taken the programmer off and refitted to make it as tight as it can be.....They are turning up tomorrow....probably to agree with me and will no doubt say that they need an accessory to cover the gap in the tiles (since the original Horstmann days)....although for past few years I have lived with an annoying hole in the wall under the last programmer....As an engineer I cannot for the life of me be convinced that the csa of these little pins trying to make contact with the wallplate can sufficiently have a low enough resistance or current carrying capacity to provide any degree of long service.....bad design as far as I can see and I reckon it IS the plate bending or contracting and expanding in a hot kitchen......We shall see......if all else fails I will show them the door and sort out a permanent fix myself.

Britmanuk · Sep 2, 2021

merlinradioltd said:
Weird one this. 3rd UP2 Programmer fitted by BG since January to replace an older version of the same type, which was a pretty basic model..(can't remember the model no). Anyway this one is a Drayton LP722 rebranded as a UP2 which should be a direct match to the existing wall plate..wired as live and neutral and then 1 is HW off, 2 is CH off and 3 HW on and 4 CH on...(so far so good). Each time the programmer fails, the effect is no CH unless HW is selected. Take the programmer off the wall plate and put it back on and it works for a few days. The wall plate has been changed as well as it was a suspected bad connection on the programmer connection pins. Fit a brand new programmer and all is well for say a month and then the same symptoms start again.

Although changing the programmer clears the fault for say a few weeks, so does taking the original off the wall plate and putting it back on....that works for a while.

Boiler fine, plenty hot water and great heat from radiators. Just when working as a twin channel this odd effect occurs. Motorised valves operating correctly and BG has changed the valve heads three times and replaced the room stat but can't pin the fault down. Back plane links set for independent, 24 hr prog and pumped system.Wiring on SM1 wallplate all ok and connections solid.

This is annoying, as when this happens the only way to get the boiler to fire up and provide the CH is to switch the HW on or I suppose would have to have the HW and CH to set to exactly the same times and lose the independent control which is not clever.

My theory so far is that the programmer is a pretty poor fit with the wallplate and the pins on the programmer seem to lose contact with the wallplate from time to time and the very act of taking the unit off and refitting might be just getting an intermittent good low resistance connection......Totally baffled.

Britmanuk · Sep 2, 2021

merlinradioltd said:
Weird one this. 3rd UP2 Programmer fitted by BG since January to replace an older version of the same type, which was a pretty basic model..(can't remember the model no). Anyway this one is a Drayton LP722 rebranded as a UP2 which should be a direct match to the existing wall plate..wired as live and neutral and then 1 is HW off, 2 is CH off and 3 HW on and 4 CH on...(so far so good). Each time the programmer fails, the effect is no CH unless HW is selected. Take the programmer off the wall plate and put it back on and it works for a few days. The wall plate has been changed as well as it was a suspected bad connection on the programmer connection pins. Fit a brand new programmer and all is well for say a month and then the same symptoms start again.

Although changing the programmer clears the fault for say a few weeks, so does taking the original off the wall plate and putting it back on....that works for a while.

Boiler fine, plenty hot water and great heat from radiators. Just when working as a twin channel this odd effect occurs. Motorised valves operating correctly and BG has changed the valve heads three times and replaced the room stat but can't pin the fault down. Back plane links set for independent, 24 hr prog and pumped system.Wiring on SM1 wallplate all ok and connections solid.

This is annoying, as when this happens the only way to get the boiler to fire up and provide the CH is to switch the HW on or I suppose would have to have the HW and CH to set to exactly the same times and lose the independent control which is not clever.

My theory so far is that the programmer is a pretty poor fit with the wallplate and the pins on the programmer seem to lose contact with the wallplate from time to time and the very act of taking the unit off and refitting might be just getting an intermittent good low resistance connection......Totally baffled.

Exactly the same problem with mine same timer Drayton Control unit. I changed everything from motherboard to thermostat you name it I bought a 2nd new you control unit. Still experiencing the same problem. Today I put the old one back after resetting it central heating working again. I will look into finding a different timer control unit when I speak to a technician because this Drayton unit clearly does not what do the job properly.... The first control unit is several years old the second control unit is brand new. Yet putting the old unit back seems to of resolved the problem for how long only God knows. But I'm absolutely convinced that it's the Drayton control unit at fault.

telectrix · Sep 2, 2021

Strima said:
If they take the valve off and replace it them it would be worthwhile to fit isolator valves to save draining down the system when it fails on 30 years time. A drain down and flush could be on the cards to get rid of any crap in the system, the whole lot may have acquired a chunk of magnetite stopping the valve from operating fully. Does the valve operate fully?

I could be talking out of my arse but would induced currents have an effect on the new programmer?

problem there is BG maintenance contract excludes drain and flush tha't chargeable at exhorbitant cost. they quoted us £800, and even worse, it was not the problem. some pipework was wrongly fitted (by them).

Britmanuk · Sep 2, 2021

As mentioned I have had exact problem changed everything from fan on boiler, motherboard, tank stat, 3 way valve, both at least twice in 2 years thermostat in hall, sensor on boiler it's lmoat a new system again.. baxi boiler, always been good. Had electrician in the check wiring..all ok... Today Changed the brand new (2 months old) Drayton, put old Drayton timer back reset timer and working.... It's been driving me mad for Over a year... And yes CH came on soentimes only when water is on but not always. If the fault continues I will change the CU for a different brand.

Britmanuk · Sep 2, 2021

sedgy34 said:
Don't think it's the programmer if you have changed it already
try getting the 3port valve plate changed its fixed to the pipework under the head of the valve

Britmanuk · Sep 5, 2021

Three days of working HW and CH, after removing and refitting Drayton, now HW not heating. So will reset Drayton remove it and see what happens....I'm 99% sure it's the Drayton at this stage.. if no joy I will buy a different make timer.

johntheo · Sep 5, 2021

Have you checked the valve in the HW position or/and switched off the power to see if the valve then motors (spring return) to the HW position, it would seem that the valve is remaining in the CH position for whatever reason, what about cylinder stat?.

Britmanuk · Sep 5, 2021

Hi thanks, brand new 3 way valve changed two times and new electric sensor head

johntheo · Sep 5, 2021

OK, but when you say "hot water not heating" you should then be able to establish with a multimeter if incorrect signal is still going to the valve or if the boiler is not getting a signal to fire up or whatever. If just switching the power off-on without removing/replacing the programmer then that would indicate not a pin problem.

Britmanuk · Sep 5, 2021

The only fix currently is when the unit is removed and replaced via the bracket.

If it continues to fail CH or HW and it changes from town to time, I'll gent a sparky in again, failing no problems with electrical, I will buy a new brand of timer.

johntheo · Sep 9, 2021

Maybe worth having a read.

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Strange fault with Drayton programmer

JD6400

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Britmanuk

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telectrix

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