Boiler not switching on, pump not running, no hot water - please help?

HazelFlorist said:

Does that tell us anything?

I'd have expected to measure some voltage there surely?

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The usual way to check for a voltage, is to check it against a known reference point. That reference point is usually the neutral terminal in a 240v mains circuit. An obvious neutral connection in that 'electrical box' is the neutral which connects to the pump - could you safely connect to that neutral with one probe, then test again? That neutral should be on terminal #2 of the connector strip.

The voltages on that connector block/ choc-bloc are the key to working out what is failing in your system.

You need to look at the Y-Plan circuit diagram I provided the link to earlier -https://www.honeywelluk.com/Documents/Installation-Guide/pdf/1083.pdf

Make a note of what voltage you are finding on each terminal in that block and report back..

This also might give you a few clues..
https://www.flameport.com/electric/central_heating/heating_wiring_Y_plan.cs4

Update...

My brother-in law is an electronic engineer and whilst not a central heating expert, came round for a few hours and with the wiring diagram and some kit, went through is all, testing along the way.

What he discovered was that the wiring was fundamentally correct and the cyl and room thermostats are working, but the timer was not giving the correct signals (Tempus 6).

Upon further investigation, we discovered a likely bad connection where the timer pins insert into the back plate (he manually jumped two of the connections with the timer off the wall and everything jumped into life). Lots of emery cloth and fiddling later and we got it to work* but it remains intermittent depending on whether we press the unit against the back plat firmly or not, confirming this is (one of) the issues, despite lots of connector and pin cleaning. Perhaps the timer is on the way out (2004)?

In addition to this, we discovered that the 3 port valve was not behaving itself again - despite heat being called for, the valve lever stayed in the left hand position for hot water only, even with the room stat way up high. I also discovered when I first went to it that the lever was loose and in the heating position, despite this not being the commanded status.

*When I say working, it still doesn't command the central heating properly (at all) - when I select heating, nothing happens - but at least when I ask for hot water, it all now works.

Also, from memory, I have never since I;ve lived here (20 years) been able to just request heating only on the timer and it do anything - nothing happens. In order for me to get central heating, I must also switch the hot water on at the same time which doesn't seem right does it? Surely I should be able to just ask for heating but with the water side off and the boiler, pump, 3 port etc do their thing and heat the house?

So - should I bite the bullet and get a new timer AND back plate? If so, what is the cheapest, reliable one? I was thinking of this... https://www.unventedcomponentseurop...9wb_DvY5xhGJDND39P0Fy4aqetfQZPRhoCIuIQAvD_BwE It seems to do everything I need?

Also looks like the 3 port valve head is intermittently not quite right - are the £30 copy heads from Amazon okay?

Any thoughts on the call for heating only and nothing happening, ever situation?

Thanks everyone for the help so far.

HazelFlorist said:

So - should I bite the bullet and get a new timer AND back plate? If so, what is the cheapest, reliable one? I was thinking of this... https://www.unventedcomponentseurop...9wb_DvY5xhGJDND39P0Fy4aqetfQZPRhoCIuIQAvD_BwE It seems to do everything I need?

Also looks like the 3 port valve head is intermittently not quite right - are the £30 copy heads from Amazon okay?

Click to expand...

Then, well done BIL...

There is not that much difference between any of the clock/timers, I value ease/simplicity of use over complexity, so I always tried to ensure they had a 1 hour override buttons for HW & CH.

I have not seen any actuator heads described as copies, but if they can be had for so little, why not buy two, one as a spare? I always have one fitted and in use, plus a spare on in the cupboard ready to fit, for when the first begins acting up. In my experience, the heads are the most frequent cause of failures in any heating system which uses them. I became quite adept at rebuilding and repairing those spring return heads.

Harry Bloomfield said:

Then, well done BIL...

There is not that much difference between any of the clock/timers, I value ease/simplicity of use over complexity, so I always tried to ensure they had a 1 hour override buttons for HW & CH.

I have not seen any actuator heads described as copies, but if they can be had for so little, why not buy two, one as a spare? I always have one fitted and in use, plus a spare on in the cupboard ready to fit, for when the first begins acting up. In my experience, the heads are the most frequent cause of failures in any heating system which uses them. I became quite adept at rebuilding and repairing those spring return heads.

Click to expand...

Thanks for the reply - money is very tight so I'll just buy one for the time being.

Could I just ask regarding my heating only question - is it correct to be able to just ask the timer for central heating (whilst the hot water side of the timer is off) and the the system to fire up the boiler, move the 3 port to 'rads only', fire up the pump and heat the house?

Logic tells me this should be possible and should work, but never in my 20 years has that request worked - I;ve always had to have the hot water side switched on in order for the central heating to come and warm the rads. It should work independently of the hot water side right? Otherwise there wouldn't be the option to make an independent request for CH only?

For the record, it's still playing up this morning and lots of fiddling with the timer whilst loose on it's mountings got it to work (effective;y sliding the pins in and out of the connector slots in the plate) - I'm wondering if the timer is fine and it's just the connectors to the backing plate? I'm pondering disconnecting the power and replacing the backing plate? Can you buy thee independently? If so, where as I can't find them online so far...

Many thanks.

If you are having trouble with the electrical wiring connections and you don't know if it's the the programmer or the backplate at fault, then how would you know which one to change? they could even both be worn. Even if there isn't a problem with the electrical connections, I always change both when fitting a new programmer so that both items are new together.

One thing that the programmer does do is to provide a 'hot water off' output for the motorised valve (grey wire). This is an essential part of putting the motorised valve in the correct position, so if there is an issue with the programmer it could be responsible for positioning the motorised valve incorrectly.

'Y-Plans' are deigned for the central heating only, in fact for most of the time once the hot water cylinder has heated up, the hot water side will be off anyway. However, there are programmers that have different settings and configurations so it is possible but very unlikely, that in your case that the the hot water may have to be on before the heating will operate. I don't recall you giving the make / model of your programmer. Sorry if I missed it.

Personally I would sort out the programmer first as you have now identified it as being faulty, then if you still have problems, then look at the motorised valve.

stem said:

If you are having trouble with the electrical wiring connections and you don't know if it's the the programmer or the backplate at fault, then how would you know which one to change? they could even both be worn. Even if there isn't a problem with the electrical connections, I always change both when fitting a new programmer so that both items are new together.

One thing that the programmer does do is to provide a 'hot water off' output for the motorised valve (grey wire). This is an essential part of putting the motorised valve in the correct position, so if there is an issue with the programmer it could be responsible for positioning the motorised valve incorrectly.

'Y-Plans' are deigned for the central heating only, in fact for most of the time once the hot water cylinder has heated up, the hot water side will be off anyway. However, there are programmers that have different settings and configurations so it is possible but very unlikely, that in your case that the the hot water may have to be on before the heating will operate. I don't recall you giving the make / model of your programmer. Sorry if I missed it.

Personally I would sort out the programmer first as you have now identified it as being faulty, then if you still have problems, then look at the motorised valve.

Click to expand...

Thanks for the reply - it's a Drayton Tempus Six - this exact one... http://www.gotogasdocs.co.uk/f/m/Dr.../Tempus 6 Installation & User Instuctions.pdf

Does that ^ influence the heating only issue? (the dip switches are set correctly on the rear).

If I buy a new timer, will it come with a backing plate? If not, where can I buy a backing plate.

I feel confident that the timer is okay, and it's just the connections that are poor and causing intermittent faults so I might try to fix this by properly cleaning everything up 'on the bench', rather than leaning into a dark kitchen cupboard. No harm in trying if it saves having to buy a new timer.

The Drayton Tempus Six programmer does provide the facility to have just the heating on without the hot water, my next question would have been about the dip switches / jumpers, so well anticipated!

New programmers always come with a new backplate. I'm not aware of them being sold separately, but then I haven't looked, as I said before, I always swap them as a pair anyway. The blackplates are supposed to be the same, and most are, but I have known them not match up particularly well across different manufacturers.

Also, there are two parts to the electrical connection for the programmer, the slots on the backplate and the pins on the programmer itself, in the case of bad connections, it is most likely to be the backplate, but it might not be, it could be the pins on the programmer.

I don't know if this is an issue in your case, but the backplate should be mounted square and flush to the wall and not twisted, sometimes they are fitted so that the plate is distorted if the wall or any back box is uneven, which can cause a bad connection. Or, the programmer isn't securely fixed to the backplate. I've also lost count of the programmers I've seen that have their fixing screws missing or the location lugs broken, that prevent the two parts making a good connection.

Thanks. I stripped, cleaned and re-made all the connections both on the wires to the back plate and also the pins and slots etc to the point they were all solid and pristine and things have not improved - till flakey and random, making me feel that it is fact the timer that is faulty?? Perhaps a dry solder joint or bad relay?

On the point of the relays in the timer, I noticed that sometimes I don't hear the relays click when I switch it to the on position (either channel) and sometimes I do - is this a smoking gun as things only work when I hear the relay. Yes the backing plate is flush and square.

It's time (pardon the pun) to buy a new timer. I'm thinking of the Drayton LP522 - any other suggestions? Just want a simple to use 2 channel.

Two other questions if I may...?

1) Why has switching the heating only on never worked?

2) Why do pins 1 and 2 (CH off and HW off) have no wires connected to them in the backing plate - they are redundant. Additionally, there are 3 cables leading to the backing plate. One of which is just mains power. The other two have multiple cables, but what I notice is that the red from one is joined to the red of the other via a connector block. Same with the black cable - joined with the back from the other cable. Any ideas why? Or why pins 1 and 2 are redundant?

Thanks.

HazelFlorist said:

Any ideas why? Or why pins 1 and 2 are redundant?

Click to expand...

Terminals 1, 3 and 4 in the timer should be occupied, that might explain why heating only has never worked.

It might be worth checking how it is wired against this...

https://www.flameport.com/electric/central_heating/heating_wiring_Y_plan.cs4

HazelFlorist said:

Why do pins 1 and 2 (CH off and HW off) have no wires connected t

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you do not need a wire in CH off but you do need wires in HW off, it has never been wired correctly

ianmcd said:

you do not need a wire in CH off but you do need wires in HW off, it has never been wired correctly

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Thanks, would that explain my inability to not request heating only? If this is required, how has it worked all these years, albeit no CH only?
So.... what do I do with two red wires joined together and two black wires joined together at the back plate?
If I split them, which ones go into the HW off and what do I do with the bare end(s)?

Any thoughts on the timer?

HazelFlorist said:

Thanks, would that explain my inability to not request heating only? If this is required, how has it worked all these years, albeit no CH only?
So.... what do I do with two red wires joined together and two black wires joined together at the back plate?
If I split them, which ones go into the HW off and what do I do with the bare end(s)?

Any thoughts on the timer?

Click to expand...

Impossible to be sure without being there to test things out, but my guess is that there has been a past issue with that timer and someone has batched it to get it to sort of work.

You need to determine where each wire goes, check it against the diagram I linked to above and install a new timer - then decide whether the valve actuator is faulty or not. It would do no harm to get one anyway, just in case, then if not needed it can be a spare.

Guess what wire goes to the programmer terminal 1? Hint:

stem said:

One thing that the programmer does do is to provide a 'hot water off' output for the motorised valve (grey wire). This is an essential part of putting the motorised valve in the correct position, so if there is an issue with the programmer it could be responsible for positioning the motorised valve incorrectly.

Click to expand...

It won't be responsible for the "no hot water" that prompted your thread, but it would prevent the heating not working when the hot water wasn't on at the programmer. Terminal 1 of the programmer connects to the motorised valves grey wire and indicates that 'hot water is not required' (ie the programmer has switched the hot water off). As a result the valve winds to the heating only position and triggers the boiler if heating is required. If this wire is missing it wont do either.

HazelFlorist said:

On the point of the relays in the timer, I noticed that sometimes I don't hear the relays click when I switch it to the on position (either channel) and sometimes I do - is this a smoking gun as things only work when I hear the relay. Yes the backing plate is flush and square.

Click to expand...

That usually signifies that the contacts inside the programmer have worn out and not switching as they should.

A simple test, if you can do it safely would be to remove the programmer and add wire links between the terminals L, 3, & 4. as per below. Leave all of the other wires as they are.



This will replicate the heating and hot water being set to 'on' at the programmer. The room thermostat and cylinder thermostat should still work, so you can test the heating, and afterwards and set the thermostat low to prevent it staying on. Also, the hot water should heat up and once hot, the boiler will go off. However, don't do this test unless you can do it safely, because the programmer will remain disconnected, the live pins of the backplate will be exposed. If you do the test and everything works as it should, then you know that the programmer is faulty.

However, in the long term, if you wish to have the heating on without the hot water the connection from terminal 1 of the programmer will need to be added.

stem said:

However, in the long term, if you wish to have the heating on without the hot water the connection from terminal 1 of the programmer will need to be added.

Click to expand...

Can I suggest the OP buys themselves a small, cheap multi- meter, which includes a continuity buzzer and learns how to operate it.

It will make identifying which wire actually belongs on terminal 1 of the timer, much easier. Looking at the Y-plan diagram, terminal one of the timer should connect to terminal 7 in the joint box + the grey wire to the valve actuator + terminal 2 of the cylinder stat..

Indeed. I'm also starting to get a bit concerned about the extended 'trial and error' fault finding, there is obviously some intermittent connection failure somewhere and possible 'arching' which if it makes its way to the boiler PCB may start causing more serious / expensive problems.