3 port valve

[SWPilipala]

Help please!

3 months ago we had no CH but HW working, so replaced 3 port valve but today we have the same issue again.
Any suggestions would be greatly received on why this would be doing this again or other areas to check as find it odd that 3 port valve would go so quickly again?

 

[terryplumb]

Was the entire valve changed ,or just the actuator head ,or just the motor? Other things going faulty could prevent c/ heating working not just the 3 port valve,

 

[SWPilipala]

Thank you,
Just the actuator but the valve was changed 18 months ago and is moving freely.
Any other likely causes?

 

[terryplumb]

Need a lot more info. Boiler make ,model. Wall stat , programmer. Is the boiler firing up on demand for central heating ( i.e is combustion taking place ,flames visible at the burner )?

 

[SWPilipala]

Glow worm 40ff boiler, danfoss cp715 programmer, danfoss HSA3 valve and Honeywell room stat.
Boiler fires for HW, won't fire for CH

 

[terryplumb]

Is the programmer on for central heating ,top left red led alight. If yes....
Is thermostat set to high 30 degrees.,.
If yes...go to boiler and turn dial fully anti clockwise to off. Wait 30 seconds and turn on fully clockwise ,listening for the sound of the fan starting. And report back.

Edit programmer to be off for hot water ,forgot, to say !!

 

[SWPilipala]

Light on programmer CH on/ HW off, thermostat turned up to 30. Tried reset of boiler but nothing.

Is there anything which can cause actuator or valves to fail?

 

[terryplumb]

When you had a problem 3 months ago ,was it that the boiler did not fire up for c/ heating or it did fire up ,but radiators were not getting hot ?? The actuators are usually quite reliable for years ,but like anything electrical you may have a dud.

 

[SWPilipala]

Same problem as now.
I guess we are just unlucky with this actuator!

Cheers for the help.