Alpha cd28c fault

[simonhick]

Hi,

I have a boiler that is driving me mad.

The boiler in question is a Alpha CD28c lpg. It is in a rented property and has not been used for a long while, although the boiler is only 3 years old.

I have had to change the lpg rig as not to current standards. Initially the boiler would not light at all. I changed the gas valve it now works on hot water no problem but on heating it runs for 30 seconds but no heat to the rads. No lock out or faults neons. Pump runs but get really hot, fan ok. It appears that water not leaving boiler into heating circuit. return hotter.

Alpha mentioned a blockage in boiler. I have completely stripped down boiler and drained system. Both clear and clean.
The boiler runs fine in service mode (rads get hot) as i used this to set up the gas valve with my gas flue analyser.
As soon as back to heating no heating? 240v at diverter valve motor ( does this send 240v back to pcb when switched)

The diverter valve body with valve and seating is clear and heat circulates with motor removed.

I am thinking of changing the diverter valve motor, but worried I have missed something?

Any advise would be appreciated as i am now sick of this boiler and spent alot of time at clients, I thought I had it with the change of the gas valve then this.

cheers

 

[Ermintrude]

Filter on return

 

[IDCHAPPY]

Are you sure the pump is running? take the head of the diverter valve and see if the hot water gets round the radiator circuit.
Usually if the problem is becoming a big pain in the bum it's worth just biting the bullet and getting the manufacturer out ?

 

[Ermintrude]

Just take out vent screw if the slotted bobbins moving you got rotation . I manually spin old girls before I juice up as blows the windings. Also rotate old or pumps that have been idle

 

[Irish]

I manually spin old girls before I juice up

Really!? You dirrrrrrrrrrrrrrrrrty man

 

[Alpha man]

DV motor!

 

[Ermintrude]

DV head makes sense as it does default to DHW. Thought op may have checked this on his own or at least when talking to alpha technically unhelpful service.

 

[Alpha man]

Oh you've spoke to them before!! LOL

 

[Ermintrude]

Nearly as blunt and ineffective as ferolli one man band.

 

[simonhick]

Once head off circuit gat hot quickly.
Alpha want £250 to visit!! Which might have been ok if I had called at start!
Cheers

 

[simonhick]

Spoke to Alpha a couple of times. To be fair the guy I spoke to when setting up gas valve was great. When the problem continued with heating circuit the Alpha engineer was not very forth coming with information on diverter valve. Just insisted it was a blockage which I cannot see as circuit get hot when DV motor removed or in service mode.
Have checked pump is spinning my removing the vent screw. All free and running.

I guess i will try DV motor as filters are clear.

Thanks everyone