Is My New Corgi (Tower) Programmer Faulty?

[plumbandplumber]

I have an ancient ch system. Think it's s plan. Fully pumped, open vent, Thorne Olympic boiler.

The old programmer started to play up, so I fitted a Corgi/Tower PR2 2 channel programmer. All went well, until I tried to run it on the programmes I set on it.

The hot water runs according to the programmed times I entered, but the heating won't come on on the programmer at it's programmed times. If I put the heating on constant, it comes on normally wether on it's own or with the hot water if that is already on. It's definitely the programmer that's not switching the heating on at the programmed times, because the three buttons under both heating and hot water light up when the programmer has turned either of them on.

Is the programmer faulty? It's not responding to the programmed times for the heating. Or is there something else? Thanks for any help and advice.

N.B. I have definitely selected 'fully pumped' in the programmer's set up menu.

 

[steadyon]

1. Have you checked that the wiring to the new programmer is the same as the old?
2. Have you checked whether there is 240V at the CH motorised valve when the programmer calls for CH heat.
3. Have you checked whether there is 240V at the output from the CH motorised valve when the programmer calls for CH heat.

The normal sequence (with mains voltage switching) is:
a. Programmer calls for CH heat by putting 240V on CH thermostat.
b. If heat required, CH thermostat puts 240V onto motorised valve motor (brown).
c. Motorised valve opens, and when open, puts 240V onto output to boiler. Normally orange.
d. Boiler fires.

 

[plumbandplumber]

1. Have you checked that the wiring to the new programmer is the same as the old?
2. Have you checked whether there is 240V at the CH motorised valve when the programmer calls for CH heat.
3. Have you checked whether there is 240V at the output from the CH motorised valve when the programmer calls for CH heat.

The normal sequence (with mains voltage switching) is:
a. Programmer calls for CH heat by putting 240V on CH thermostat.
b. If heat required, CH thermostat puts 240V onto motorised valve motor (brown).
c. Motorised valve opens, and when open, puts 240V onto output to boiler. Normally orange.
d. Boiler fires.

Thanks for your reply.

1. The wiring on the backplate needed to be changed. The old Landis and Gyr programmer had L and N wires plus hw on to term 3 and heating on to term 4. The Corgi needed hw on to 4 and heating on to 6 plus the usual L and N connections.

2.No I haven't checked the 240v when programmer calls for ch heat, on programmed ch times because the programmer says that ch heating is off. When I put it on constant, the boiler/pump come on and heating works normally. The programmer isn't calling for heat at the programmed times - that's the problem. I have to turn the programmer to constant to get ch heating on.

3. As above, programmer not calling for heat on programmed times (heating on lights not illuminated on programmer - nothing from pump/boiler). Only get lights illuminated for ch heat and pump/boiler on if I select constant on heating mode selector.

Sorry it's confusing. I don't understand how I can manually select heating by selecting 'Constant', but the heating won't come on with 'Auto' - even though the programme times I put in are correct.

 

[Ric2013]

From what you're saying above, I really would be inclined to the opinion that the fault is in the programmer, or simply you haven't figured out how to use it properly. As I cannot see how any other fault in the system, or wiring could cause the programmer itself to fail to call for heat at the right times.

I've just looked at the instructions for that programmer and I must admit it looks like one of those ones that is almost impossible to understand unless you have the programmer in front of you.

This model? : Google

I think you have independent programmes for hot water and central heating, which could be the error?

The manual over-ride are the respective [+1Hr] buttons which should allow you to turn on either function for an hour up to 9 hours (try to select 10 hours to switch back off). Try these and let us know if those, at least, work as they should.

 

[SavageW]

Read 3.1.2 an make sure the programmer is set for the correct type of system you have,makes reference to if it’s in gravity mode the heating will not come on without hot water being on

 

[plumbandplumber]

Thanks for your reply. Yes, the programmer was faulty. I took it off and wired it up to just a live and N 240v power supply. The heating would only come on on 'Constant' - wouldn't respond to the timings - which were correctly programmed.

It's fully pumped system and I programmed timer for fully pumped as you mention.

Have swapped for a Drayton, which works as expected. Unfortunately it's not the only problem with this old system, but I have posted another thread.

Thanks for taking the time to help.