Your help required ... Three way actuator not working

[Ray1000]

The heating at my 94 year old neighbours bungalow is going to be changed later this year ... in the meantime it seems the only way to get heat to the radiators is to latch the actuator on the three way valve.

Q1. Is it likely I could find and fix whatever is causing it not to work of its own accord.

Thank you
Ray

 

[terryplumb]

Latching the valve alone wouldn't fire the boiler. Does the boiler fire up under a demand for domestic hot water from programmer and cylinder thermostat , I assume it does ?
The most likely problem is a failed motor in the 3 port valve,although it could be other things.

 

[Ray1000]

Thank you Terry,

Yes it does - I think what I observed was this - The programmer was on timed calling for hot water and heating - the boiler was stood and the radiators were cold - I assumed the tank stat was satisfied with the HW temp - the room stat was at 23 degrees - I slid the actuator lever across and the boiler started, when I popped round later the radiators were hot and have been since.

It had been running in this fashion for a few weeks, I had un-latched it the other day when the outdoor temp rose. I think it still responds to the room stat when latched.

With the system being quite old and it having mainly skirting heating it may not be capable of getting to 23 degrees in the hallway.

 

[terryplumb]

If programmer is set for central heating only,and thermostat calling for heat,does boiler fire up and radiators heat up ,or not ??

 

[Ray1000]

I'll just go round and check

 

[terryplumb]

With 3 port valve not latched by the way !!

 

[terryplumb]

Deleted , duplicated post

 

[Ray1000]

It was all stood on timed - turned the HW to OFF and the CH to ON and the boiler lit up - turned the room stat down the boiler stopped - turned it back up and the boiler started - just like you would expect !

The actuator would still have been latched from earlier.

 

[Ray1000]

Sorry Terry I had gone round with out seeing the unlatch instruction

 

[terryplumb]

If the actuator is manually latched open ,the boiler shouldn't fire up when only c/ heating is selected. So something is amiss.
As it's working,in a fashion, I suppose it's ok until the upgrade is done.

 

[Ray1000]

Thank you very much Terry, if there are any other tests I could do them tomorrow.

 

[terryplumb]

Just to be sure, Are you saying ,with the valve not manually latched open ,the boiler will not fire up for central heating ?
If that's so, it sounds like the motor isn't working in the valve ,and it's microswitch is also being activated manually ( when it normally wouldn't be),when the valve is latched open.
What exactly is due to be changed later this year ?

 

[Ray1000]

I don't think it will fire up for CH only unless latched but I'll check it again in the morning.

When you sat "latched open" Terry does that mean with the lever hooked over the step and locked in place?

If so, where is the valve diverting water to when latched?

My neighbours son who lives 100 miles away is intending having a complete new system, everything would be renewed.

 

[terryplumb]

Yes ,latched open = you manually move the lever ,hook it over and lock it in place.
At that position ,the gate is then open to both ports ( in other words ,water flows to hot water cylinder and also to radiators).
When it is not latched open, the water can only flow to the cylinder.

 

[Ray1000]

Thanks for that Terry I'll copy it to my phone for future reference.