Boiler not firing, no H/W or C/H

[adam1984]

Hi, just returned from holiday and the boiler /CH is not working. My brother looked after the house an assures me that everyday the HW and CH came on when the timer kicked in and the just stopped working yesterday. I have the water and CH set to constant at the moment and the boiler is not even firing and no pumps etc are working. I have a standard boiler with hot water tank.

The room stat was changed a few weeks ago to a Honeywell DT90 and has been working for 2 weeks fine.

Any ideas?

 

[Dan Robinson]

I have a standard boiler with hot water tank.

That narrows it down a bit.

Pilot light on?

Clocks lighting up?

Throw as a bone and we'll try and help.

 

[adam1984]

Hi,
The pilot light is on.
The boiler is a Thorn BMI Apollo.
The room stat is a Honeywell DT90e.
The pump is a red Groundforce selectric.
The water-CH switch is a switchmaster SM805.

The boiler is old and has no digital graphics. The room stat is illuminated and reading correctly.

 

[Dan Robinson]

IS the boiler getting 230v to the switched live terminal?

What Zone valves arrangement do you have?

 

[adam1984]

It's a Honeywell sundial Y diverter.

There is 230v to the boiler mains.

There is 0v to the room thermostat when the water / heating is off and 230v between live and switch live when the water and heating is turned on.

How do I check the switch live at boiler?

Everthing was working fine and correctly previously so I think the wiring is correct.

Thanks for your help so far.

 

[plumbplumb]

Does the pump run?

 

[adam1984]

The pump is not running.

Normally when I turn the water and heating on together the pump starts up and the boiler fires up (you can hear their distinct noises)

Neither the pump is starting and boiler firing.

 

[adam1984]

There appears to be no power at the pump. I tested across live and neutral and it showed 0v

 

[plumbplumb]

Test the boiler/pump live. If you have a mid position valve as you say this is the orange wire.

Turn your heating on you should have 240v on the white wire to the valve and also 240v on the orange wire.

If you are not getting 240v on orange suspect an issue with the midposition valve

 

[plumbplumb]

Also when you test live-neutral you should also test live-earth and neutral-earth this will help eliminate problems with faulty neutrals

 

[matt1e]

It's a Honeywell sundial Y diverter.

There is 230v to the boiler mains.

There is 0v to the room thermostat when the water / heating is off and 230v between live and switch live when the water and heating is turned on.

How do I check the switch live at boiler?

Everthing was working fine and correctly previously so I think the wiring is correct.

Thanks for your help so far.

if you are getting 230v between live and switched live at the stat then that suggests the stat is off

you can check for a switched live at the boiler between the terminal marked "on" and neutral also check between "on" and earth too as already advised

Matt

 

[adam1984]

Done as said and getting 230v across both

 

[plumbplumb]

230v across both what??

the stat or the on at the boiler?

 

[adam1984]

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Ok. FCU to boiler on. Water and CH set to constant.

At Boiler:
230v between ON and Live.
0v between ON and Neutral.
0v between ON and Earth.

230v between Live And Switch Live at Room Stat.

With Regards to the orange and White wires. I checked between live and orange and Live and White in the big Junction box and got 230v. Is that the correct way?

There isn't a orange or white cable in the boiler.

Will anymore photos help out?[/img]

 

[furryneddy]

Where does the switched live from the room stat go - if you follow/trace it back to the boiler terminal you can check it is actually signaling the boiler to fire - the fact that the stat's lit up like a xmas tree and there's power to the boiler doesn't mean that what its signaling (the stat) is getting back to the boiler. oh and you won"t find the orange and white wire from the diverter/"big box" in the boiler casing.