Hot Water Problem

[bsr]

Hi

I have an S plan system with Honeywell 2 port zone valves. Yesterday there was no hot water despite the timer being on for HW. I manually latched the HW zone valve to open. I then turned up the CH thermostat and the boiler fired and heated HW and CH.

Now I can manually move the zone valve open and shut with minimal resistance. If I open it manually, it stays open even when not latched. If I try and push up the lever to latch open, it drops down again from latch to auto but stays in the open position. This gives us enough HW for now. Boiler thermostat is at 65c so no danger of overheating the unvented.

Would you replace the motor (£20) or the whole actuator (£60)?

Should I test the microswitch between grey and orange to see if there is continuity when valve open, and if so microswitch is OK?

Then I can test across the motor leads (brown/blue) to check if motor is 2400 Ohm and if not its faulty?

Or do you just swap the whole thing out anyway?

Any other tips?

Thanks

 

[terryplumb]

Fit a complete new actuator

 

[TimboTwo]

I replaced the actuator on mine a couple of years ago with a £28 one from CPS. Replaced it earlier this year as the metalwork inside had distorted and was jamming.
Genuine Honeywell £55 from Screwfix.
https://www.screwfix.com/p/honeywel...-replacement-powerhead-22mm-compression/326fv

 

[bsr]

I changed the head. When I use the programmer to call for hot water the actuator makes a buzzing sound but the lever doesn't move. I can move the lever easily by hand.

Does that suggest the problem is the valve and not the actuator? What would you do? Try and turn the valve spindle with grips, and if that fails drain down and replace the whole valve?

 

[ianmcd]

I changed the head. When I use the programmer to call for hot water the actuator makes a buzzing sound but the lever doesn't move. I can move the lever easily by hand.

The lever doesnt move on its own, with the HW switched off, manally move the lever and you should feel a bit of reistance, then when you release it you will her a whirring noise, with a demand for HW made , manually move the lever and you should feel no resistance and it wont return when let go, this is the correct function, if it is doing this but the boiler is not firing you have a faulty micro switch or it isnt wired correctly, putting the lever into the Man position will not fire the boiler

 

[bsr]

That all happens except the boiler doesn't fire when I push the lever to the end.

Here's the wiring centre. Can you see anything which looks wrong? Unfortunately the wiring doesn't match the guide on the wiring centre. Possibly because I have a system boiler? I changed the wires one by one from old to the new.

Number 7 has a brown and blue so I'm suspicious of it now.The HW zone valve has the flex coming in under number 10.

 

[CBW]

Who carried out the wiring? Number 7 states grey, but none are in number 7, also did you purchase the correct actuator? - there appears to be a white wire, usually found in 3 port mid position valves.

 

[bsr]

Wiring centre all done before I moved in so at least three years ago. Boiler and controls are 15 years old so probably all that old.

The zone valve leaflet said white was rarely used and should be safely isolated so that's what I did. I think it's something to do with pumped CH/ gravity HW.