Horstmann HRT3 wired incorrectly

[n0v1ce1]

I had a new boiler, programmer, cylinder and thermostat installed last March.

When it got colder this winter I noticed that at times the heating was not coming on, despite the programmer being on and the temperature being way below the thermostat setting.

I looked at the instructions for the thermostat. They said that failure to connect neutral to terminal 4 "will result in incorrect and random switching".

I booked the annual service with the same man who installed the system and asked him to look at it. It turned out he had not connected the neutral wire as directed.

Unfortunately connecting it has not fixed the problem. Is it possible that having the wiring incorrectly connected for 10 months could have damaged the thermostat?

By the way my installer is now suggesting I pay him for a new 'digital' programmer to deal with the issue.

 

[D_Hailsham]

Unfortunately connecting it has not fixed the problem.

Can you make the boiler come on by turning the stat up or down?

If so, which way do you have to turn it?

If not, which programmer do you have?

Is it possible that having the wiring incorrectly connected for 10 months could have damaged the thermostat?

No.

 

[n0v1ce1]

Can you make the boiler come on by turning the stat up or down?

If so, which way do you have to turn it?

If not, which programmer do you have?.

Thanks for replying. The red pilot light on the thermostat comes on when I turn the dial clockwise but the boiler does not come on.

The programmer installed is a Horstmann CentaurPlus C27.

Since I noticed the issue I have set the timings on the programmer so that the CH is 'on' for most of the day and the heating eventually comes on at some stage.

 

[n0v1ce1]

[quote The red pilot light on the thermostat comes on when I turn the dial clockwise but the boiler does not come on.[/quote]

I should qualify this by saying that is sometimes reacts to the CH thermostat temp being adjusted but not always.

That is what has been puzzlng me all along. Why would the control work some times and not others. Maybe the issue is with the programmer that was fitted?

I have managed to draw up how the connections in the airing cupboard have been done. The fitter used the wiring that was in situ for the original boiler. I have uploaded into my images folder. This was very easy to see, I have not tried to look into the connections at the boiler and programmer end.

 

[D_Hailsham]

Some photos would be helpful.

 

[n0v1ce1]

Some photos would be helpful.

Sorry, I thought the photo had been linked in

 

[n0v1ce1]

Sorry, I thought the photo had been linked in

View media item 90383

 

[D_Hailsham]

Sorry, I thought the photo had been linked in

I was meaning some photos of the actual devices (pumps etc), showing how they are connected together.

The diagram raises a lot of questions, which might be answered if the pics were available.

 

[n0v1ce1]

[/quote]I was meaning some photos of the actual devices (pumps etc), showing how they are connected together.

The diagram raises a lot of questions, which might be answered if the pics were available.[/quote]

Ah! Will take some and upload

 

[D_Hailsham]

Just noticed that you have edited the diagram. The three top bubbles still have ?, e.g "From Programmer re CH?". Are they guesses?

What is the one labelled "From immersion re HW?" connected to at the immersion (HW cylinder?)? This is where pics would help.

 

[n0v1ce1]

Just noticed that you have edited the diagram. The three top bubbles still have ?, e.g "From Programmer re CH?". Are they guesses?

What is the one labelled "From immersion re HW?" connected to at the immersion (HW cylinder?)? This is where pics would help.

Here are some photos

The top wires are my guesses. If I am right about the immersion one it must be connected into the immersion system wires under the boards.

I am also guessing where the other two cables shown in the top part of the diagram come from. I have not taken the cover off the programmer to check the connections under there yet.

View media item 90384View media item 90385View media item 90386View media item 90387

 

[D_Hailsham]

The square box held on by some net curtain wire is the cylinder thermostat
The cable going from the top of the cylinder to the wall is for the electric immersion heater. It's provided for emergency use, i.e when the boiler goes wrong.

View media item 90384
The silver/black device is the pump

View media item 90386
The blue box is a mid-position valve

View media item 90387
It is a Y Plan system. Here is the wiring diagram:

You don't say which boiler you have, so I don't know if pump overrun is required.

View media item 31288

 

[n0v1ce1]

You don't say which boiler you have, so I don't know if pump overrun is required.

I was guessing that the HW cylinder stat would need to be linked into the immersion system somehow - but as my username suggests I am very much a novice.

The boiler is a Worcester Greenstar Ri
the CH stat is a Horstmann HRT3

Thank you for the circuit diagram

 

[D_Hailsham]

I was guessing that the HW cylinder stat would need to be linked into the immersion system somehow.

No. It doesn't have to be linked to the electric immersion heater.
The immersion heater is fed from the fused spur on the wall and controlled by its own thermostat under the round silver cover on the top of the cylinder. Normally the immersion heater is switched off as the cylinder is heated by the boiler.

The boiler is a Worcester Greenstar Ri

The boiler needs pump overrun.

Your wiring diagram
The three cables at the top are still a mystery.

The one labelled "From immersion" is definitely NOT that. I think it's from the programmer.

The pump does not appear to be wired correctly

There is no cable to the boiler!

Remove the programmer from the wall, take a pic of the back plate and post it. We can then see which wire does what.

 

[n0v1ce1]

Remove the programmer from the wall, take a pic of the back plate and post it. We can then see which wire does what.

I will do that.

I think there are 2 cables coming up from the programmer, one for HW and one for CH. The other I now think is from the boiler.

I have noticed that the pump and the valve both whir away when the timer is on but the boiler is not fired up (this applies for both CH and HW).

Is that how it is supposed to work?

To my untrained mind I would expect the pump and valve only to come on if the thermostats also 'tells' the boiler to fire up.

There is still the mystery of why the boiler sometimes but not always refuses to fire up even though the CH stat indicates temp is under the setting.

No matter what though, I have lost confidence in the installer and think I need another installer to come to my house and look at the wiring.