Timer Not Firing Boiler

[Burridge69]

Hi everyone, hoping someone can give me an idea of what’s wrong. I have an Ideal Logic+ System 18 (serviced in Dec 23), Drayton LP522 timer & Drayton Combistat.

No matter what I do I can’t get the boiler to fire. Putting heating or hot water to on does nothing, advance boost, nothing. Restarted the boiler a few times, even turned the house electrics off in an attempt to restart the timer.

Any ideas? Thank you all in advance!

 

[Exedon]

First have you tried reseting boiler?
As its a system boiler your going to have 3 port motorised valve or 2 two ports.
To check if you actually have a switched live to boiler your going to need a multimeter and be competent to use it.

 

[Deleted member 267285]

+1 for motorised valve(s). Has anything changed recently?

 

[ericmark]

Thank you @Exedon saved me looking it up. There are a series of Honeywell plans, C, S, Y, W to name a few, and variations one each one, to stop the boiler and pump trying to circulate water through a system which is not open many of the motorised valves have little V3 micro switches inside and these are prone to failing, near impossible to strip and replace, so it is normally a case of renewing whole head or actuator there are two types in common use two port and this three port, the latter as quite a few bits inside and not the easiest to test.

So step one post a photo of your valves, so we have an idea what we are dealing with.

 

[Burridge69]

Thank you for everyone’s help so far. I have checked and can only find 1 actuator, it’s a 3 port Drayton MA1.

 

[Deleted member 267285]

Thank you for everyone’s help so far. I have checked and can only find 1 actuator, it’s a 3 port Drayton MA1.

Turn off the power to the timer - should be a fused connection unit by it. Then turn the power back on and select hot water only and see if the boiler fires up. Make sure that the cylinder isn’t already satisfied, if it is, just increase the temperature for testing purposes

 

[Burridge69]

Just gave that a go, my switch turns the boiler off with the timer. Boiler fires for a couple of minutes when turned back on before going off, but I’ve put HW to on and will see if the boiler stays on with it. Small black tab on the actuator has moved though so that’s promising?

 

[Deleted member 267285]

Just gave that a go, my switch turns the boiler off with the timer. Boiler fires for a couple of minutes when turned back on before going off, but I’ve put HW to on and will see if the boiler stays on with it. Small black tab on the actuator has moved though so that’s promising?

Sounds promising, although it shouldn’t move for hot water only.

 

[Burridge69]

Boiler has since turned off (booo) HW still on, tried CH too and still nothing

 

[Deleted member 267285]

Boiler has since turned off (booo) HW still on, tried CH too and still nothing

Could very well be the programmer then, might be dropping the live feed. Maybe worth calling someone out? You could also turn the power off, confirm it’s dead and put a link wire between L and hot water?

 

[Harry Bloomfield]

Can you confirm if the pump is running? It may make an obvious noise, or if it has a large chrome screw cover, covering the end of the shaft, remove it, and poke a screwdriver in and you will feel the shaft rotating. Expect a small amount of water to escape, with the chrome cover removed.

 

[DP]

Do you get a radiator symbol displaying on the boiler display.
What is the pressure like

 

[ericmark]

Given are the internal wiring of three port valve and general Y plan wiring diagram. In theroy there should be three wires to both the programmer for DHW and the Thermostat for DHW, the extra third wire turns the DHW off when set to off by either the programmer or the thermostat, so power to three port valve when DHW is not wanted.

With an old boiler it did not matter too much if water went through the hot coil when not required, with a new boiler the returning hot water will cause the boiler to modulate (turn down) so I have seen where the off wire is not connected to one of the devices.

But the main point is all the micro switches in the three port valve do nothing if only DHW is called for, it is only the programmer and the tank thermostat which does anything when only DHW is called for, so the valve should not move, default with no power to valve is DHW.

The lever on the valve can hold the valve half way for bleeding, it activates one micro switch, and when the other has failed I have seen that latching the lever on has allowed central heating to work, even with a faulty micro switch.

Fault finding is hard, as the three port valve back feeds, so you need a volt meter as need to see not just line, but line at 230 volt. Use of volt sticks will not work with the Y plan for fault finding.

John Ward does a very good youtube

to how they work.