Honeywell smartfit Y plan system fault

[buddybugoy]

Hello everybody i am new here and i was hoping someone could help me with my central heating problem.
I have an Ideal (Classic) boiler with a Honeywell smartfit Y Plan system. The problem started when my central heating stop working and a F4 fault showed on the room unit. I have checked the 3 port valve for blockage and it appears to be working fine as i can turn the brass from A to B. I then changed the smart fit actuator for a brand new one from ebay. The problem appeared to have been fixed and we had heating and hot water overnight BUT the next day the same problem showed up again (F4). I performed a system check on the Room Unit and this time its not detecting the Y system too as it shows (0) invalid system. Im complete lost now and i don't know whats wrong here.

To summarize everything
1. F4 fault (even when actuator was changed with same brand)
2. Invalid system

 

[D_Hailsham]

F4 means the 3-port valve is jammed. Honeywell suggest:

a) Check Actuator is fitted to valve
b) Check Actuator drives Valve full travel. If not, remove Actuator and check Actuator will drive for at least 10 seconds
c) Use manual lever on Actuator to free Valve
d) Check Valve for blockage and clear

Invalid System

Ensure that all plugs are securely connected into the Base Unit and check that the system selection switch on the Base Unit is in the Y-Plan position before switching on at the fused spur.

Switch on the system.

The actuator will run for a short period (less than a minute). Then hold down the HOT WATER and HEATING programme override buttons for 5 seconds. The Room Unit will display a number in the range 0-3. Verify that a Y-Plan system has been detected (displays 1).

If number 1 is not displayed, re-check connections.

 

[buddybugoy]

Hi thanks for your reply i already done that but still the problem persist. There is no instruction on the manual to say what to do if the Room Unit does not detect the Y system. I have checked all the connection and i even move the switch on the base unit from Y to S then back again but to no avail. Although it doesn't appear on the fault code apart from the persistent F4, i suspect this two faults are causing the problem. I can manually turn on the heating but whenever i put it on Auto then the problem starts. Im begining to wonder if the fault is on the base unit or the Room Unit for that matter.

 

[D_Hailsham]

Have you tried resetting the system (see Smartfit instructions) - make a note of all settings first?

If this fails, I think you are probably correct - the base unit is faulty.