heatslave 20/25 no central heating

[sparticus]

hi,
hot water works fine. when you turn on ch, it fires up the boiler and runs for about 4 mins and then stops.no lockout, 1.5bar, pump seems to turning and the activator arm seems to be move ok when selecting ch/hw.
I opened the pump screw and spun the pump by hand and the heating worked for the set hour. Not sure if that was a coincidence. But I can tell if the pump is weak?
Any ideas please?

 

[dontknowitall]

Sounds like a pump issue to me. The pump sends the water around the system so if no cold water is being pumped back to the boiler then the thermostat will kick in to turn the boiler off.

 

[diamondgas]

hi,
hot water works fine. when you turn on ch, it fires up the boiler and runs for about 4 mins and then stops.no lockout, 1.5bar, pump seems to turning and the activator arm seems to be move ok when selecting ch/hw.
I opened the pump screw and spun the pump by hand and the heating worked for the set hour. Not sure if that was a coincidence. But I can tell if the pump is weak?
Any ideas please?

The heatslave needs the pump to work for both hot water and heating so it's unlikely that one will continue to work whilst the other does not! Chances are you have an fault with whatever is controlling the direction of water! IMO

 

[kimbo]

Have you checked to make sure the diverter valve is actually diverting the water, the cogs sometimes wear and slip.

 

[sparticus]

The heatslave needs the pump to work for both hot water and heating so it's unlikely that one will continue to work whilst the other does not! Chances are you have an fault with whatever is controlling the direction of water! IMO

Sorted it. I forgot about the magnetic 'boiler buddy' inline and when i checked it it was clogged with ####. I checked after a year and it didnt need cleaning, but 18 months after that it was blocked. Do I need some more inhibitor? This thing has either done a great job or is the system gonna just keep blocking,any views on the 'boiler buddy'? thnx

 

[diamondgas]

Sorted it. I forgot about the magnetic 'boiler buddy' inline and when i checked it it was clogged with ####. I checked after a year and it didnt need cleaning, but 18 months after that it was blocked. Do I need some more inhibitor? This thing has either done a great job or is the system gonna just keep blocking,any views on the 'boiler buddy'? thnx

The boiler buddy, is that the plastic sphere? They're pretty small so will block depending on how much crud was left after install Just clean it and refit IMO

 

[sparticus]

yes its a plastic (usually clear if not gunked up) oval blob. I cleaned it and the water flow is now fine. a flow error light would be handy mr bosch.