No hot water

[Asa]

Hi. Please help me identify the fault.

I have c/h but no h/w.

I have a green Star ri boiler and a nest thermostat. I have a thermaq cylinder.

If I call for hw boost or schedule hw heating the boiler doesn't fire up, the motor valve doesn't open.

If I put heating on and manually open the hw/motor valve the talk fills with h/w

Also the immersion doesn't seem to hear the cylinder either.

So I figured faulty thermostat on the cylinder, changed it... Fault persists... So I'm stumped.

Is it the motor valve? If so why no immersion? Maybe it's both things? i.e. 2 faults... Haven't used the immersion since cylinder was fitted.

Whole system, apart from boiler is 2 years old. Guessing boiler is maybe 10 ? (done before we moved in)

I'm surviving lockdown with putting the heating on a couple of hours with the hw valve opened but it's not ideal, especially when the sun comes out!

Thanks in advance for any help you could give.

 

[picasso]

Do you have a multimeter (for measuring voltages) and know how to use one ?

 

[Asa]

Hi. Yes I have a multimeter...I could give it a go? Haven't used it before....

What should I check please?

 

[picasso]

You need to see if you have 240vac on the brown to the hot water valve, make sure the programmer is calling for heat.

 

[Asa]

Thanks. Will check that. Will set nest to boost.

What is the chain of command? Nest calls for heat, valve opens, thermostat on cylinder says ok, boiler fires?

 

[picasso]

Nest calls , then cylinder stat through to brown on valve, if 240 on valve it proves nest and cylinder stat are ok.

 

[CBW]

Is it one motorised valve or 2?

 

[Asa]

there are 2... i presume one for central heating and one for hot water, i think i have identified which is which. (one gets warm when central heating is on)

 

[CBW]

Then you need to test as per @picasso for 230vac live on the brown wire.

 

[Asa]

Thanks everyone, finally got a chance to have a look. Turned out to be the synchro motor on the motor valve £9 and a very uncomfortable half an hour in a cupboard... But all working again!

 

[ianmcd]

Thanks everyone, finally got a chance to have a look. Turned out to be the synchro motor on the motor valve £9 and a very uncomfortable half an hour in a cupboard... But all working again!

wouldnt affect the Immersion in any way though

 

[Asa]

You're absolutely right... There is a possibility that was never working, since install, I never had reason to check it.... So that's the next issue to sort....

Best get the multimeter out again!

 

[ianmcd]

You're absolutely right... There is a possibility that was never working, since install, I never had reason to check it.... So that's the next issue to sort....

Best get the multimeter out again!

A good chance your immersion heater will have two switches, one in the same cupbourd/space as the Cylinder and another usually in the Kitchen, they are wired in series and both have to be on to use the immersion heater, also check the consumer unit the RCD might be turned off