Heating Controller Being overridden (UK)

[Tony P]

When the heating and hot water are off the MA1 will still be energised to the hot water position

When you turn the heating on does the lever move to the other position

Do you have a meter so you can check what incoming voltage you have

I thinking this problem may be down to an intermittent incoming mains issue

Thanks, I will check the heating control, I don't have a voltage meter so will get a plumber/ heating engineer to check for me. Do you thing the intermittent mains issue could be the micro switch inside the actuator? Thanks for your help Tony P

 

[brianmoooore]

Your system is a Y plan , unfortunately, which makes fault finding more difficult, and I'm also unfamiliar with your model of valve, in spite of having been installing heating systems for 40 years.
Y plan is more complicated because the boiler is only sometimes operated by the valve's switch, whereas with S plan it is always operated by the valves' microswitch.
A further complication is if you have a boiler which has frost protection. An externally positioned (to the boiler and airing cupboard) thermostat then fires up the boiler in cold weather, and, of course, this can become faulty.
Getting back to your original question, yes, a faulty microswitch in the valve can cause what you describe. It's happening with my own heating system at the moment. About every two weeks or so, we find the towel rails in the house to be permanently hot, and although the valves are closed (towel rails don't go through valves), the pump and boiler are on. Thumping the hot water 2 port valve provides a cure for the next couple of weeks.

 

[Tony P]

Your system is a Y plan , unfortunately, which makes fault finding more difficult, and I'm also unfamiliar with your model of valve, in spite of having been installing heating systems for 40 years.
Y plan is more complicated because the boiler is only sometimes operated by the valve's switch, whereas with S plan it is always operated by the valves' microswitch.
A further complication is if you have a boiler which has frost protection. An externally positioned (to the boiler and airing cupboard) thermostat then fires up the boiler in cold weather, and, of course, this can become faulty.
Getting back to your original question, yes, a faulty microswitch in the valve can cause what you describe. It's happening with my own heating system at the moment. About every two weeks or so, we find the towel rails in the house to be permanently hot, and although the valves are closed (towel rails don't go through valves), the pump and boiler are on. Thumping the hot water 2 port valve provides a cure for the next couple of weeks.

Thanks Brian, couple of more questions if I may, if I replace the actuator do you feel it is OK to use a junction box rather than change the wiring behind the control panel, is it better to bite the bullet and change the type of actuator? If so does that mean changing all the pipe work? Thanks again for all your help

 

[UNG]

Thanks Brian, couple of more questions if I may, if I replace the actuator do you feel it is OK to use a junction box rather than change the wiring behind the control panel, is it better to bite the bullet and change the type of actuator? If so does that mean changing all the pipe work? Thanks again for all your help

If your MA1 actuator is not the quick release type then you will have to change the valve as well

 

[Tony P]

If your MA1 actuator is not the quick release type then you will have to change the valve as well

It is quick release, thanks again Tony P

 

[Tony P]

I'm not familiar with that particular actuator. W M H stands for Water, Mid position and Heating. Best to look up the instructions for that actuator to see how to manually operate it.

Sorry missed this earlier, looks like I need to change the actuator, it is quick release so will replace and use a junction box rather than rewire. Thanks for your help.

 

[brianmoooore]

What sort of junction box do you have in mind? It will need to have clamps to secure the cable, be of adequate IP rating, and be capable of joining several wires.
Much better to do the job properly and change the whole lead back to the wiring centre.

 

[UNG]

Sorry missed this earlier, looks like I need to change the actuator, it is quick release so will replace and use a junction box rather than rewire. Thanks for your help.

Given that the cable on the MA1 actuator is at best a metre long I don't understand why you are adding a junction box

 

[brianmoooore]

When you have the actuator off, check that whatever it moves in the valve works smoothly without catching. It's not unknown for debris or scale to build up and limit the travel of the actuator slightly, preventing the switch working as it should.

 

[Tony P]

Given that the cable on the MA1 actuator is at best a metre long I don't understand why you are adding a junction box

Morning, I'm only a basic DIY person, can manage a junction box but I'd not want to take on rewiring the control box. Cheers

 

[brianmoooore]

You can, no doubt, manage a junction box IF you understand the requirements for that junction box, and are able to source a suitable one, which is the reason for my last post.

 

[Tony P]

You can, no doubt, manage a junction box IF you understand the requirements for that junction box, and are able to source a suitable one, which is the reason for my last post.

Hi Brian, thanks for getting back, I've been recommended to get this one,

Regin REGE105-5 way Plug/Socket with Strain Relief​

1.