New External Boiler - Frost stat wiring question/ concerns

[stu550]

Just had a new outside (Worcester Camray 18/25) oil boiler installed that replaced an internal boiler.

I am slightly concerned by how it is wired for frost protection.

The exisiting frost and pipe stat are wired as they were before, inside the utility room and if it gets cold enough, they fire up the boiler. No problem here, apart from the fact, that the boiler has no constant power to it so is not using/ benefitting from its own built in frost thermostat....

So, if the CH/HW is off, and the house is say 7 degrees inside and its below freezing outside, then the boiler is not going to fire up?

I mentioned this to the installer and he said that the boiler housing is VERY well insulated and it won't be a problem?

My question is basically, should the boiler have a constant live to it and rely on its own frost stat?

I thought one way of sorting this would be to turn up the inside frost thermostat and wire it in series to the boiler... then, if the temperature inside drops, the frost thermostat to the boiler will come into operation?
Or will it not work like this?

All advice/ help appreciated.

Thanks.

 

[45yearsagasman]

My question is basically, should the boiler have a constant live to it and rely on its own frost stat?

Of course it should. I've just read the install instructions. Your installer obviously forgot that requirement.

 

[ianmcd]

Your boiler requires a permanent live regardless of any further frost protection you have in place

 

[stu550]

Thanks. Suspected what I thought.

But why should it have a permanent live other than for the frost protection?

 

[ianmcd]

the pump is controlled by the boiler and if you dont have a permanent live then the pump will shut down when the programmer switches off and the overheat stat will trip, the boiler will keep the pump running till the boiler is cool enough if it has a permanent live

 

[stu550]

Is this the pump overrun or whatever it's called?

Is it required for this boiler?

All the pump, stats, power, valve etc is wired into a Honeywell Wiring Centre at the moment...! Is that not right?

 

[ianmcd]

look on page 27 of your installation instructions and you will see this


Any external device connected to the
boiler must take its power supply from
the boiler only and must NOT have a
separate supply.
See the following pages of electrical
diagrams for details of different systems


The boiler has fault indicator lights and these cant illuminate if the switched live is not calling and you dont have a permanent live

 

[stu550]

On page 29 it has a wiring diagram. On page 30 it has a diagram for a system boiler where the pump is controlled too- I don't have a system boiler.

Page 29 just shows a live and switched live. There is no mention of wiring a pump so don't think this is an issue on mine?

But I agree to see the faults you need it to have a live.... But won't the faults show when the programmer is calling for heat and there is a fault?

I still think it needs a live for the thermostat mind. Just working out whether it could be wired in series with the current frost stat I have if I turn it up....

 

[xr4x4]

Holly crap, it's not difficult...

Cant you replace the cable to the boiler with 4 core cable and give it a permantly live, it obviously needs one..l

 

[dcawkwell]

Your installer is a numpty and your boiler will freeze solid damage the heat exchanger and leak as soon as the first freeze occurs
if it doesn't have a live feed so it can fire when freezing.

 

[45yearsagasman]

Very expensive ice maker

 

[ianmcd]

On page 29 it has a wiring diagram. On page 30 it has a diagram for a system boiler where the pump is controlled too- I don't have a system boiler.

Page 29 just shows a live and switched live. There is no mention of wiring a pump so don't think this is an issue on mine?

But I agree to see the faults you need it to have a live.... But won't the faults show when the programmer is calling for heat and there is a fault?

I still think it needs a live for the thermostat mind. Just working out whether it could be wired in series with the current frost stat I have if I turn it up....

You came on here asking for advice and you have been given the correct advice many times your boiler requires a permanent live, up to you if you ignore that advice good luck if you need a call under warranty

 

[stu550]

Ian

I realise it has to have a permanent live. I get that.

You mention about the pump being controlled by the boiler but is this only the case for a system boiler that I don't have? As far as I can tell my boiler does not control the pump. When the heating programme stops, so does the pump, boiler etc.

Page 27 you refer to obviously isn't from the same manual I am reading.

 

[stu550]

These are the questions (from post above) that are unanswered and im struggling to understand correctly:

Is this the pump overrun or whatever it's called?

Is it required for this boiler?

All the pump, stats, power, valve etc is wired into a Honeywell Wiring Centre at the moment...! Is that not right?

Stuart

 

[ianmcd]

Modern boiler software incorporates many things like daily pump kick when boiler not in use and temp demand trends etc just put a permanent live into the boiler it needs it simples