Potterton Powermax HE and CM-Zone system

[flipper321]

Have recently had a CM-zone system installed (HR80s on the rads CM67z controllers)

However when turning new zones on the boiler very often locks out with an A02 error. When starting up from cold we haven't had a problem, only when starting a new zone with another zone already running.

Anyone know any reasons why this may be?

TIA

 

[flipper321]

Should have mentioned that I have checked for air in the system and that reported pressure is fine.

 

[baxpoti]

A02 normally represents a pump fault.

 

[flipper321]

That's what I'd heard, but in full normal operation the pump/boiler work fine.

We've had underfloor heating fitted downstairs in an extension off the existing boiler - is it possible the pump operation of this is in some way causing the trouble?

 

[simond]

If I interpret the chronology of your tale correctly, I suspect a wiring fault (causing the boiler to be called on when there is no heating load).

How are you controlling the UFH from CM Zone?

 

[flipper321]

UFH is controlled using an HC60NG as a zone valve controller.

The boiler is definitely not being asked to fire when there is no load (I've checked).

The Cm-Zone system appears to be working as I'd expect - (boiler only on when rads / UFH CM67z are requesting heat), it just seems the boiler doesn't like something the CM-Zone system does when either turning off a zone, or turning on another when already fired up.