Potterton Prima turning on and off

[West Country]

Hi everyone

I have an issue with my potterton prima boiler and would love some help. It works fine when either CH or HW are on but when they are off the boiler will fire up briefly and cut out again, it appears to be random and for 1\2 sec or severely seconds, it will continue doing this. I am turning off the power over night to stop it doing this.

My system is and old gravity-fed one, so I have HW or HW and CH. It had been working fine until last week, because the boiler seemed fine when CH or HW are on then I assumed (wrongly) that it was a control problem. Which is why I changed the old rotary dial switchmaster for a hive mini, but I still have the issue. This makes me think it's a problem with the boiler making it fire up without a signal from the controller.

 

[West Country]

I've attached a video so you can hear the noises.

 

[Ric2013]

I've attached a video so you can hear the noises.

Where?

 

[Deleted member 120897]

So you have an issue with noise and random firing? Noise could be lots of things, random firing sounds like motorised valve failure

 

[West Country]

Video so you can hear the noise

 

[West Country]

So you have an issue with noise and random firing? Noise could be lots of things, random firing sounds like motorised valve failure

So the motorised valve is for CH if I select HW only will this remove the input from the motorised valve and prove the fault?

Excuse my ignorance but I thought the motorised valve shut off the CH side of the system and didn't have an input to the boiler. I can hear when it closes and I certainly only remember hearing it operate when the heating is set to turn off.

 

[Deleted member 120897]

Video so you can hear the noise
View attachment 80397

Sounds like something is struggling like the pump or motorised valve.

 

[Deleted member 120897]

Might be best posting some photos of what you have valve wise and pump, etc.

 

[West Country]

So here you go. Top of boiler pipe work. I have a junction box, the controls (formally the switchmaster now hive) are wired into it. Live and neutral wired to the junction box via the controller Motorised valve to the junction box, junction box to the boiler. There is also a wire from the junction box going up stairs which a assume goes to the hot water tank. The pump is on the hot water and the motorised valve on the heating. I checked and I could hear the motorised valve close when I selected hot water without heating.View attachment 290356View attachment 290357View attachment 290358.

 

[West Country]

So here you go. Top of boiler pipe work. I have a junction box, the controls (formally the switchmaster now hive) are wired into it. Live and neutral wired to the junction box via the controller Motorised valve to the junction box, junction box to the boiler. There is also a wire from the junction box going up stairs which a assume goes to the hot water tank. The pump is on the hot water and the motorised valve on the heating. I checked and I could hear the motorised valve close when I selected hot water without heating.View attachment 290356View attachment 290357View attachment 290358.