Heating not working

[Nic79]

I have very little experience of plumbing but from your site so far I have managed to get my heating working temporarily but need further assistance!

My central heating will only work with my Honeywell diverter valve in the manual position - when in auto the pump works, the boiler ignites and the pipes to and from the boiler and pump get hot but the pipes after the honeywell are luke warm moving to ice cold the further away you go.

I have tried replacing the synchron motor but this had no affect....just wanted to check if anything else could cause this problem before replacing the complete valve?

Any assistance on this would be gratefully received.

Thanks

Nic

 

[MANDATE]

The problem with using it in the mid position is that once the HW is satisfied it's supposed to move to CH position.
Now it either moves to CH or not.
If it does move to CH and boiler does not light, it will be a micro switch problem.
If it does not move to CH position, then it could be due to fault in wiring (ie low or no voltage on grey wire) or the other micro switch in actuator head or resistance due to stiff spindle.
If you can remove the head off the spindle, you can test spindle and verify if valve can go to the 3 positions without the spindle having effect.
You can measure the voltage on the 'grey' wire with a meter (not a mains screwdriver tester).
Suggest you do search on 3 port valves. It would be far easier for you if you understood how the actuator head worked.
I suppose you have the boiler stat set lower than the the cylinder stat so the HW never gets satisfied as a make shift method!

 

[Nic79]

Hello,

Thanks for replying so promptly...

I don't think I explained my Honeywell properly, sorry not really done anything with this system before

It is a 'V4073A1039'.....it has 'Auto' on one side and 'Man/Open' on the other side, it has no markings for a mid position!

When the heating is on and the lever is in the 'Man/Open' position the radiators are hot, if the Hot Water comes on during this time the lever moves over towards the 'Auto' side finishing somewhere in the middle and the radiators start to cool down but the hot water works fine! But if the lever is on the 'Auto' side to start with the Hot Water works fine but the CH does not, no heat gets to the rads at all!

Hopes this helps explain things a little better, if you need more information please let me know and I will do my best to have a look!

Thanks again for any assistance you can provide

Nicola

 

[MANDATE]

The valve basically starts at the HW position and is driven across to the midpositon then if necessary is driven further across to the CH position.
The motor in the actuator head drives against a spring so that when power is removed the spring wil unwind the motor.
Form the CH position it may unwind or drop back to either mid position or HW position depending what the demand is and whether or not that demand is satisfied.
The lever has nothing to do with the operation of the valve, it is provided to assisting filling the system after drain down. It is used to turn the valve to the mid position where it is held by a latch. After filling the lever should be returned to auto. (ie taken off the latch). whilst on the latch it can't return to HW only position.
However if there is a fault, a temporary method to get some heat is to latch the lever in the mid position. When in this position normally both HW and CH get an equal share of water, but only until HW is satisfied. At this point then valve should automatically move to CH position. Also the power to light the boiler changes.
Because HW is satisfied the cylinder stat no longer provides the power, so an different source is provided through a micro switch in the 3 port valve.
When HW is ok but no CH it is usually due to the micro switch being faulty, or it has not been triggered because the valve did not reach it. Now that may due to a different micro switch or it may be the motor, or a stiff spindle.
It's highly likely a replacement actuator head will solve the problem, but it would not be wise to replace it before checking that the power source is there.
This means making sure there is 230 volts on the 'white' wire when CH on with room stat turned up.
And more important, there is 230 volts on the 'grey' wire when HW is turned OFF and again when HW is ON and satisfied.
Do remember when HW and CH are both turned off, the 'grey' in the valve is still live, so make sure all power has been removed by removing fuse, when replacing the head