Heating electric controls running hot/ burning, oil heating

[Avo Mk8]

Would the mechanical clock/control s solve the problem?

A mechanical 2 channel timer like the Screw*** one I suggested earlier (there are other types available) would I think do the job. I don't have personal experience of running a synchronous motor from a modified sine wave inverter, but the Crouzet type clock motors are usually pretty robust (other than in 3 port valves - which you don't have!)

Edit - I do see mention on a forum re off-grid users that mechanical timers in older (eg) washing machines are fine with MSW inverters.

If you normally have regular water and heating on/off periods every day of the week it would be a practical substitute. You might need to change the wiring onto the bracket that comes with a new timer.

But you did mention you would like a more powerful inverter, so a replacement 'pure sinewave' version might also solve the problem using your current timer, which still seems to be working!

 

[timhoward]

I understand what you are saying about manual operation, I saw that switch myself but how would we turn on the heating with the digital panel gone, just use the main power switch?

I don't want to confuse the issue too much, as answering this leads you away from the best solution - changing the inverter or using less fussy time switch(es).
The answer - Inside the two port valve is a switch arranged so when the valve opens the boiler fires. The system is conventionally arranged so the time controller and room stat (if any) control whether the valve opens or not, and if the valve is open the boiler will fire.
So as long as it's been wired the conventional way then turning the time switch off, and moving and hooking the lever on the heating valve should result in the boiler firing, the pump starting, and the heating coming on. (In this mode there is usually no thermostatic control of it, it will stay on until manually turned off again.)
It is not a given it's been wired like this though.
In any case, whether this works or not, it's best to focus on solving the primary issues.

 

[Avo Mk8]

I don't want to confuse the issue too much, as answering this leads you away from the best solution - changing the inverter or using less fussy time switch(es).
The answer - Inside the two port valve is a switch arranged so when the valve opens the boiler fires. The system is conventionally arranged so the time controller and room stat (if any) control whether the valve opens or not, and if the valve is open the boiler will fire.
So as long as it's been wired the conventional way then turning the time switch off, and moving and hooking the lever on the heating valve should result in the boiler firing, the pump starting, and the heating coming on. (In this mode there is usually no thermostatic control of it, it will stay on until manually turned off again.)
It is not a given it's been wired like this though.
In any case, whether this works or not, it's best to focus on solving the primary issues.

Hi Tim, forgive me, I'm not an authority on this, but I was under the impression that latching a 2 port lever does not operate the microswitch, at least not on Honeywell valves. Plumbers maintain that the lever is for draining the system, not a substitute way of fully opening the valve. It may be different for different makes of valve, but I'm just suggesting there's a possibility this might not work! I apologise in advance if I'm wrong

 

[timhoward]

Hi Tim, forgive me, I'm not an authority on this, but I was under the impression that latching a 2 port lever does not operate the microswitch, at least not on Honeywell valves. Plumbers maintain that the lever is for draining the system, not a substitute way of fully opening the valve. It may be different for different makes of valve, but I'm just suggesting there's a possibility this might not work! I apologise in advance if I'm wrong

You are right. When latched the lever stops short of the micro switch. I forgot that.
All the more reason to fix this properly!

 

[speedystu]

A mechanical 2 channel timer like the Screw*** one I suggested earlier (there are other types available) would I think do the job. I don't have personal experience of running a synchronous motor from a modified sine wave inverter, but the Crouzet type clock motors are usually pretty robust (other than in 3 port valves - which you don't have!)

Edit - I do see mention on a forum re off-grid users that mechanical timers in older (eg) washing machines are fine with MSW inverters.

If you normally have regular water and heating on/off periods every day of the week it would be a practical substitute. You might need to change the wiring onto the bracket that comes with a new timer.

But you did mention you would like a more powerful inverter, so a replacement 'pure sinewave' version might also solve the problem using your current timer, which still seems to be working!

Thank you very much, I studied some electronics years ago, never knew I'd be this worried about sine waves thanks very much you and everyone who contributed to this answer .

 

[brianmoooore]

The Danfoss 2 port valve, which I have installed hundreds of, over the years, definitely operate the micro switch when the manual lever is engaged.