Heating and hot water digital programmer

[Stuckinarut]

Before the renovation work, we could switch on the heating independent of the hot water.

A C-plan still works this way (I think)

Is it possible that the plan was changed when the renovation work took place?

Yes, definitely. As I said though, if you trace where that black cable goes and trace it back to a wiring center or whatever you may just find the other one (if it’s not been removed)

 

[ericmark]

C, Y, S and W Plans are the basic design, these can all be added to, the C Plan came in three variations, the basic had no control of domestic hot water, the next in summer the boiler only ran when required, and the last you could turn off hot water and control its temperature. I am assuming should be last version, but when repairs done, this was not followed.

 

[Alan12]

A C-plan still works this way (I think)

Yes, definitely. As I said though, if you trace where that black cable goes and trace it back to a wiring center or whatever you may just find the other one (if it’s not been removed)

Ok thanks. Why would finding the other motorised valve help you solve the issue here? Just so I understand what you’re thinking the issue is?

 

[Alan12]

C, Y, S and W Plans are the basic design, these can all be added to, the C Plan came in three variations, View attachment 376915 the basic had no control of domestic hot water, the next View attachment 376914 in summer the boiler only ran when required, and the last View attachment 376913you could turn off hot water and control its temperature. I am assuming should be last version, but when repairs done, this was not followed.

Thanks. I only see one motorised valve in that last diagram, just checking, but are you saying that the last version which allows independent control of hot water and heating would only have one motorised valve?

 

[Stuckinarut]

Ok thanks. Why would finding the other motorised valve help you solve the issue here? Just so I understand what you’re thinking the issue is?

Find another valve and it could be component failure, if not, could be the design or wiring issue.

 

[RandomGrinch]

But this is not following a standard plan

It could be a C Plan like this...

@Alan12, from this photo...

It appears that a five core flex joins to a black and red twin and earth, and a red, yellow and blue triple and earth.
Does this white flex go to the controller, or somewhere else?
If the cable is a R,Y,B triple and earth, none of your other pictures show a cable with these colours, so we may still be missing a junction somewhere.
There could be another clue to the wiring layout, if we can see inside the junction box to the zone valve, and see where the cable leads to.

Only other thing coming off the pipework is the circulating pump.

Also, where does the cable to the pump connect to?

 

[ericmark]

The old programmers had a mechanical interlock and an electrical switch to change from 10 to 16 programs, 10 for C Plan but 16 for other Plans, but your C Plan seems to have the 16 options (they count off).

I look at the beams, and wonder where the boiler is compared with the hot water tank?

I look at the arrow on the motorised valve and then three-way split. That does not seem to

tie in with the diagram for C Plan with motorised valve on the DHW. Basic C Plan

no motorised valve.

 

[Alan12]

The old programmers had a mechanical interlock and an electrical switch to change from 10 to 16 programs, 10 for C Plan but 16 for other Plans, but your C Plan seems to have the 16 options (they count off).

I look at the beams, and wonder where the boiler is compared with the hot water tank?

I look at the arrow on the motorised valve and then three-way split. That does not seem to View attachment 376938 tie in with the diagram for C Plan with motorised valve on the DHW. Basic C Plan View attachment 376939 no motorised valve.

The boiler is in the garage, the hot water tank is in the attic

 

[ericmark]

I am trying to work out some test to find out what system you have. I assume a basic cistern, ⁣but likely a thermostat, which likely connects to the motorised valve. Old programmers had a slide to stop one selecting central heating without domestic hot water, and often a switch, both only accessible when the programmer is removed. Few new systems seem to be geared for use with C Plan, Hive is an odd one out, but likely even that would not work with your system.

The standard backplate

is used for programmers and thermostats, in fact even programmable thermostats. I looked at the LP 241 programmer and I see

although this says G = thermo-syphon, in your case, because of the motorised valve, likely needs setting to P, I have linked to instructions. Interesting to know which way the link is. Maybe someone else can think of a way to work out what you have.

 

[fixitflav]

The boiler is in the garage, the hot water tank is in the attic

Do you have a roomstat and cylinder stat?

 

[stem]

I suspect that the motorised valve is not fitted to the HW cylinder, but to the CH which would rule out a C-Plan.

This theory is based on the direction of flow arrow on the motorised valve and the manual by-pass fitted after it, which would normally be there to maintain a flow of water when radiator TRV's are closing. Which is not a requirement of a hot water cylinder.

Sorry it doesn't directly solve the problem but may give food for thought......

 

[fixitflav]

I suspect that the motorised valve is not fitted to the HW cylinder, but to the CH which would rule out a C-Plan.

Could be, but the valve and p/w look like 28mm to me, which is a bit OTT for the CH circuit.

 

[Mister Banks]

Could be, but the valve and p/w look like 28mm to me, which is a bit OTT for the CH circuit.

My boiler flow and return pipework is 28mm so not unusual.

 

[ericmark]

I also had a problem, we tend to say, it did work, so what has changed, but with mine can't really see it had ever worked after the garage was converted to a flat. I asked my daughter, if radiators got warm in summer, the answer was no, but after correcting the fault clearly they did get warm.

So we know there is a single two port motorised valve, a lifestyle LP241 dual channel programmer and a pump, and both DHW and CH come on at same time, does not matter what is set. And there is height boiler to tank for thermo-syphon to work.

I had the same, reason was one wire from programmer to boiler was open circuit, so all it could do was switch on/off. So is there a tank thermostat seems a good question.

But with one two port motorised valve, can't be either S or Y plan as we know them, seem to remember the head will come off those motorised valves, so what happens if removed, and the valve stays closed, even if the head opens. If the pipes in/out of the cylinder stay cold, we know the valve controls the DHW, one would expect something not to work.

 

[fixitflav]

My boiler flow and return pipework is 28mm so not unusual.

Maybe on older systems, with gravity HW, not on a fully-pumped system. But we'll see, hopefully!

When we know what stats the OP has we'll be able to tie it down better