Potterton Profile, hot water no heating

[Nessie91]

I would be grateful for any assistance possible with the following problem I have with my Potterton Profile 50e boiler and associated controls.

The system appears to be fully operational when the programmer is calling for hot water, but if calling for heating, nothing happens.

I have changed out the programmer, thermostat and 3port zone valve head for new items, (now running with Horstman Centaur 7 & C27 stat and programmer respectively, and new salus 3pt zone valve head).

Prior to the change of the valve head the valve was defaulting to DHW only, now at least the valve is operating as it should, but boiler will not start up unless the hot water is calling.

Is there anything I have missed or is there a component in the boiler itself which may be causing this fault.

Thanks in advance

 

[petit_pablo]

Wiring issue fella
The boiler wont know whether hw or ch is being called for.

Do you have access to a mutimeter and know how to test voltage with it?

 

[Nessie91]

I've got one somewhere but all the replacements have been direct, with no wiring alterations and all was fine yesterday morning.

 

[petit_pablo]

Well something isnt right between progammer and boiler.

You need to know whats getting voltage and what isnt

 

[JohnD]

did it work correctly since you changed all those parts and reconnected the wires?

what has happened since it last worked?

what happens when both HW and CH are calling?

the correct motorised head signals to the boiler when to turn on. With Drayton and Honeywell the 28mm valve has one more wire than the more common 22mm one.

 

[Nessie91]

No the system has not worked correctly since all the parts were changed, except the valve now operates properly

Nothing has happened since it last worked, except I've changed out all the components

When DHW & CH are calling, 3pt valve in mid position and water is getting around the rads and to the cylinder

Salus valve is 22mm, head works with both, with 5 wires to wiring centre.

 

[picasso]

Make sure the orange wire from the 3 port valve is correctly connected, its easy to screw down on to the insulation and not realize.

 

[JohnD]

No the system has not worked correctly since all the parts were changed

This certainly suggests an incorrect connection.

 

[Nessie91]

I've checked the 3pt valve connections to the wiring centre and the boiler at least now acknowledges the call for heat, the fan starts but then stops. If I put the hot water on the the boiler fires.

Any suggestions?

 

[picasso]

The boiler isint acknowledging the call for ch, the boiler cant tell the difference between a call for hot water or central heating, you have a wrong/loose connection on your wiring.

 

[Nessie91]

The boiler must be acknowleging the call for heat from the CH side as the boiler now reacts by activating the fan, but will not go through to firing up. But if I then call for hot water too, the boiler fires straightaway.

 

[picasso]

Sorry me old mate but I am gonna have to give up on this one, good luck getting it sorted.

 

[JohnD]

does the pump start on call for CH?

 

[Nessie91]

All controls off, then CH on and calling, pump moves to mid position and fan activates but boiler doesn't fire. Call for hot water and all OK.

Any suggestions for what to check/do next?

 

[JohnD]

pump moves to mid position

Surely you mean "motorised valve moves to mid position"

But does the pump start?