Honeywell CM927 - suggestions to settings?

[D_Hailsham]

Directly to socket.

It turns the boiler on and off.

That's eliminated two potential sources of the problem.

Having read the installation instructions relay box is only around 15cms from boiler as opposed to 30cms - will this make a difference?

The metal of the boiler could be interfering with the signal, that's why they specify a minimum of 30cm. How far apart are the controller and relay in normal use and how many walls between them?

I tried the Test Communication - green led flashed every 6 seconds as described. I put it back to Auto and although flame was on again no green led on relay box.

The flame does not mean that the boiler should be running. It's explained in the Troubleshooting Guide on page 14 of the User Guide. It's all part of the TPI control system.

 

[jem16]

The metal of the boiler could be interfering with the signal, that's why they specify a minimum of 30cm. How far apart are the controller and relay in normal use and how many walls between them?

Around 10/12 metres. 3 walls between them,

The flame does not mean that the boiler should be running. It's explained in the Troubleshooting Guide on page 14 of the User Guide. It's all part of the TPI control system.

I read that.

I made sure I put the target temperature up by at least 3/4 degrees above room temp.

This morning when it didn't come on, room temp was 17 degrees and target temp was 21 degrees.

 

[D_Hailsham]

The metal of the boiler could be interfering with the signal, that's why they specify a minimum of 30cm. How far apart are the controller and relay in normal use and how many walls between them?

Around 10/12 metres. 3 walls between them

The three walls could cause quite a drop in signal strength. Is there another place you could fit the relay box? Where was the old thermostat located? If there were three wires (L, N and Switched Live) to the old stat, you could easily relocate the relay box there.

This morning when it didn't come on, room temp was 17 degrees and target temp was 21 degrees.

Is that 17 degrees as shown on the CM control unit or from a separate thermometer?

Was the flame showing?

What happens if you turned the temperature up at the control unit? Will the boiler eventually light? At what temperature?

How far from the controller is the nearest radiator?

Do you have a TRV on the nearest rad? If so is it set to Max?

 

[jem16]

The three walls could cause quite a drop in signal strength. Is there another place you could fit the relay box?

I did ask about putting it in the same location as the timer that was there - unfortunately this wouldn't work as it was only 3 core wire going to the boiler (or 2 core as it had L, N and E?). The timer had a separate mains feed next to it.

Where was the old thermostat located? If there were three wires (L, N and Switched Live) to the old stat, you could easily relocate the relay box there.

Old thermostat had not been in use for 10 years when boiler was replaced from a gravity rise and fall system to a combi boiler. It was an old-fashioned analogue thermostat which is still on the wall but I doubt if wiring still exists at boiler end.

Is that 17 degrees as shown on the CM control unit or from a separate thermometer?

CM control unit itself.

Was the flame showing?

Yes.

What happens if you turned the temperature up at the control unit? Will the boiler eventually light? At what temperature?

Nothing happened and I even took the control unit out and stood next to the relay box.

How far from the controller is the nearest radiator?

About 3 metres.

Do you have a TRV on the nearest rad? If so is it set to Max?

Yes and yes.

Since moving it to a different location in the living room it seems to be working at the moment. It's sitting at its target temperature and has been for around 40 minutes since wsitching on at 4:30.

 

[htgeng]

There is a hidden setting to change the max temp to 21c rather than the default 30c. Its worth doing this so some numpty can't set it to 30 which then causes the house to overheat and increase your gas bill considerably.

 

[simond]

We've had a few duffers of these (although nowhere near the levels of the Drayton stuff) and if the problem persists I'd suggest just changing the unit.

Our merchant just runs another one out and I change it over in a couple of minutes, usually after a 45 min van journey.

PS: Don't like the clip on the later radio receiver, what a useless and fiddly design. Has anyone at Honeywell considered a Philips screw? They know we have a suitable screwdriver because that is what we need to do the wiring terminals up with.

 

[D_Hailsham]

I did ask about putting it in the same location as the timer that was there - unfortunately this wouldn't work as it was only 3 core wire going to the boiler (or 2 core as it had L, N and E?). The timer had a separate mains feed next to it.

The Linea should have a permanent supply. Is the connection from the timer separate from this?

If the timer has been removed, what's to prevent you using the old timer mains feed to supply the L and N terminals of the relay box. The two wires to the boiler can then go to terminals A and B - do not link L to A.

Old thermostat had not been in use for 10 years when boiler was replaced from a gravity rise and fall system to a combi boiler. It was an old-fashioned analogue thermostat which is still on the wall but I doubt if wiring still exists at boiler end.

Are you saying that for ten years the only control was the timer and the boiler thermostat?

Is that 17 degrees as shown on the CM control unit or from a separate thermometer?

CM control unit itself.

Was the flame showing?

Yes.

What happens if you turned the temperature up at the control unit? Will the boiler eventually light? At what temperature?

Nothing happened and I even took the control unit out and stood next to the relay box.

Since moving it to a different location in the living room it seems to be working at the moment. It's sitting at its target temperature and has been for around 40 minutes since switching on at 4:30.

Definitely sounds like a loss of communication.

If you can relocate the relay box to where the old timer was, this may help.

 

[jem16]

The Linea should have a permanent supply. Is the connection from the timer separate from this?

The Linea has a permanent supply next to it in the garage. The timer had a different permanent supply next to it in the house.

If the timer has been removed, what's to prevent you using the old timer mains feed to supply the L and N terminals of the relay box. The two wires to the boiler can then go to terminals A and B - do not link L to A.

The installer was not happy putting it in the same position for 2 reasons.

1. He said it had to go next to the boiler. ( the instructions do more or less say this)

2. The boiler and relay box would have 2 separate mains feeds - you yourself said this was dangerous on my original thread before it was installed.

Are you saying that for ten years the only control was the timer and the boiler thermostat?

No each radiator, bar one, has TRVs - temperature was controlled in each room.

Definitely sounds like a loss of communication.

If you can relocate the relay box to where the old timer was, this may help.

The odd thing is that even standing next to the relay box with the controller in my hand made no difference - it still wouldn't come on when I increased the temp. There were no leds showing on the relay box, either green or red.

 

[jem16]

We've had a few duffers of these (although nowhere near the levels of the Drayton stuff) and if the problem persists I'd suggest just changing the unit.

I did wonder about that.

The communication test seemed positive with the green led flashing every 6 seconds as it said. There was no red led to indicate loss of communication (except for the one occasion when I carried out my radio controlled clock and the controller together and right next to one another - clock is normally in kitchen so I don't imagine it would have been causing a problem)

PS: Don't like the clip on the later radio receiver, what a useless and fiddly design.

I take it you mean the table top stand?

 

[D_Hailsham]

The installer was not happy putting it in the same position for 2 reasons.

1. He said it had to go next to the boiler. ( the instructions do more or less say this)

2. The boiler and relay box would have 2 separate mains feeds - you yourself said this was dangerous on my original thread before it was installed.

The first is rubbish. My boiler is downstairs in the kitchen and the relay is upstairs outside the airing cupboard where the wiring centre and other components are located.

I agree that I said it was not advisable to have two separate supplies, but if it solves a problem and both supplies are clearly marked that there is a second supply, I would use both supplies.

No each radiator, bar one, has TRVs - temperature was controlled in each room.

But there was no thermostat to turn the boiler off when the house reached temperature.

There were no leds showing on the relay box, either green or red.

If comms were lost the red light should be on permanently or flashing. So it looks like you have a faulty unit.

Take it back and get it swapped.

 

[jem16]

The first is rubbish. My boiler is downstairs in the kitchen and the relay is upstairs outside the airing cupboard where the wiring centre and other components are located.

I did wonder if it was more ease of installation. However instructions also say it should be in an open area which the small understairs cupboard where the timer was isn't.

I agree that I said it was not advisable to have two separate supplies, but if it solves a problem and both supplies are clearly marked that there is a second supply, I would use both supplies.

At least they were on the same circuit breaker. They were not, however, clearly marked but could have been.

But there was no thermostat to turn the boiler off when the house reached temperature.

Correct - which was why I went for a programmable thermostat.

10 years ago when the boiler was installed, thinking then was not to use a thermostat but to control each room individually. It seems to have changed again with thermostats now placed as standard.

If comms were lost the red light should be on permanently or flashing. So it looks like you have a faulty unit.

Take it back and get it swapped.

As I paid for supply and fit it would be the installer's job to replace.

It hasn't done it again since though - again odd. I thought it had 5 minutes ago when radiator had got cold and flame was showing. However temp was at target temp. Radiator has now got hotter again so it appears to be doing its job.

I have now turned on optimisation so am going to monitor the situation over the next few days. I will probably give the installer a ring too and tell him what has happened.

Thank you for all your help and advice.

 

[D_Hailsham]

Please let us know how you get on (in this topic).

 

[jem16]

An update as promised.

Since moving it to its new position in the living room there has been no problem.

I have now turned on optimisation - this works both on the first time setting in the morning and the evening time setting. So far I have opted for;

7am - 19C
8am - 10C ( normal weekday unoccupied)
5pm - 21C

Weekends - 7am become 9am at 19C and 10:30 at 10C ( May change this depending on how often I feel I am at home during the day at weekends)

With optimisation, heating has come on at various times depending on temperature. The last couple of days in particular have been really good as the unit has acted as I wanted it to. Normally at this time of year the timer was set for 4:30pm and often came on even though I wouldn't have felt the need for heating. Yesterday and today heat was needed in the morning but because of higher daytime temperatures, heating more or less stayed off in the evening - I think I noticed a very slight warmth in radiators late in the evening as temperature dropped again.

What I have also noticed is that it keeps the temperature pretty much at what I have set it to within 0.5C up or down - checked this out with another digital temperature guage. Radiator has gone from warm, luke warm to more or less off as required.

So far I am very pleased with the way it's performing.

As time goes on I may modify temperature settings as required until I decide on my best options.

 

[D_Hailsham]

Thanks for the update.

Since moving it to its new position in the living room there has been no problem.

That's good

I have now turned on optimisation - this works both on the first time setting in the morning and the evening time setting.

That's very interesting. The general consensus is that optimisation only works on setting number one. How do you know that it also works on the evening setting? Are you actually arriving home at 5pm every weekday evening?

So far I have opted for;

7am - 19C
8am - 10C ( normal weekday unoccupied)
5pm - 21C

Presumably you set it to a lower temperature overnight.

What I have also noticed is that it keeps the temperature pretty much at what I have set it to within 0.5C up or down - checked this out with another digital temperature gauge. Radiator has gone from warm, lukewarm to more or less off as required.

Exactly as I have found it. The rads sometimes give hardly any heat. The one in this room has a surface temp of 40C at the moment.

 

[jem16]

That's very interesting. The general consensus is that optimisation only works on setting number one. How do you know that it also works on the evening setting? Are you actually arriving home at 5pm every weekday evening?

I'm on holiday from work at the moment so have been able to monitor what's happening.

First day I switched optimisation on I had it set for 5pm and that's when it seemed to turn on (although my son arrived for dinner just at that moment and I took my eye off it). So following what you said about it only being the 1st setting I changed the time to 4;30pm. Next day I noticed it had come on around 45 minutes before 4:30pm so it seemed to be reacting to optimisation. I have now turned it back to 5pm and it was definitely coming on before 5pm to get up to 21C at 5pm.

Presumably you set it to a lower temperature overnight.

Yep - forgot that bit. At 10pm it's set for 10C.

Exactly as I have found it. The rads sometimes give hardly any heat. The one in this room has a surface temp of 40C at the moment.

Not quite sure how to measure the surface temp of a radiator.

The only thing I find a bit strange is the fact that the flame is on but as the room temp is 21.5C and target temp is 21C no heating is on. I know you gave me the reason from the manual but it just seems odd anyway.