HC60NG gives up on Xmas day!!

[D_Hailsham]

The HC60NG controlled by my CM927 seems to have given up. When a call for heat occurs the green light on the relay box turns on and immediately turns off. The same thing happens if I press the button on the relay box. I have also tried new batteries in the Prog-stat and it makes no difference.

I assume this means the relay box is dead, unless someone can suggest a alternative explanation, so a new relay (BDR91) is required.

The date code on CM927 is 2407 (week 24 2007). I bought it, new, in 2007, so it has done nine years, which means the relay has switched on and off thousands of times.

 

[Steelmasons]

If you would like to know how to override the receiver just hollah??..
Merry Xmas Mr Hailsham.

 

[D_Hailsham]

If you would like to know how to override the receiver just hollah??..
Merry Xmas Mr Hailsham.

That would be most helpful.

Seasons greetings to you, also.

 

[Steelmasons]

That would be most helpful.

Seasons greetings to you, also.

If I recall a link is required between L and C... or is it A and C??????...I'm sure it's not B....
Wishing you a warm Xmas..

 

[D_Hailsham]

I'm very warm; thanks to a well insulated house and some thermostatically controlled electric heaters.

 

[hertsboilers]

If I recall a link is required between L and C... or is it A and C??????...I'm sure it's not B....
Wishing you a warm Xmas..

lol.

 

[DP]

Suspect will be the power supply is shutting down when relay operates. Have seen this happening on other timers/ programmers

 

[D_Hailsham]

Suspect will be the power supply is shutting down when relay operates. Have seen this happening on other timers/ programmers

Do you mean the supply to the HC60NG's L and N terminals, or the supply within the H60NG to the internal relay?

 

[Agile]

Many of the small thermostat receivers produce a low voltage DC power line inside by using an AC rated capacitor as a voltage dropper. Depending on the current drawn these are often about 0.47uF.

I have not seen any evidence on the net of them often failing on your device but it is a very common failure on the Drayton RF stat and there are several people selling the caps or a repair service on Ebay.

These caps often lose capacitance and consequently the supply line voltage falls and is unable to operate the circuit correctly.

Of course it could be other faults in your particular case.

For a CM927 to last since 2007 seems very lucky. I often see the TX unit having failed after only three years or so. Pity really as they are one of the best for ease of use.

Tony

 

[Steelmasons]

I'm very warm; thanks to a well insulated house and some thermostatically controlled electric heaters.

Why are using electric heaters Mr Hailsham??
Surely link the boiler/receiver until such time a replacement Honeywell is fitted.

 

[Agile]

Quick and easy way to keep warm if boiler is down.

A tenant I visited recently in a HA flat was given two fan heaters to keep warm and told to keep them when the boiler was finally repaired!

Tony

 

[Steelmasons]

Quick and easy way to keep warm if boiler is down.

Tony

Although the boiler is not "down"......just a simple external controls issue.
I'm fooked if I'd break out the leccie heaters when a simple bridge across a couple of terminals would have the heating back up and running...

 

[jackthom]

In my house I'd do almost anything to avoid having to resort to electric heating.

Sadly although I've done my best over the years it's not quite as well insulated as I'd like.

 

[DP]

Do you mean the supply to the HC60NG's L and N terminals, or the supply within the H60NG to the internal relay?

It is impossible to speculate how low voltage is derived in the receiver to power the electronics.
A relay will have operate voltage and a hold voltage, which is lot less than operate voltages. I wonder if supply voltage collapses when relay operates hence the relay releases.
If you want to play with the receiver, check the diodes and smoothing capacitor.

As steel says, bridge the switching contact in the receiver, boiler will work

 

[D_Hailsham]

Why are using electric heaters Mr Hailsham??
Surely link the boiler/receiver until such time a replacement Honeywell is fitted.

You won't have any temperature control if you do that as the boiler will be permanently on.

Already have the electric heaters, which have thermostats so they are not on all the time. A new BDR91 is due to arrive tomorrow so not much electricity will get used.