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Hi
First post; sorry it's so long, just trying to provide all of the information as I've spent a while diagnosing the problem already. My current theory is a sticking microswitch in the 3 way valve. I'm hoping someone can tell me if I could be on the right lines and if so, what I need to buy to fix it.
The boiler has been running every day to provide hot water, so I don't think it's anything catastrophic...
I have a very old Trianco oil boiler. There is a room stat and in the airing cupboard there is a hot water tank, a British Gas branded controller,a Grundfos pump and a Drayton MA1 3 way valve.
The boiler, and the pump definitely work and the lever on the 3 way valve moves the way I'd expect when I operate the controller. The room stat was a Tado and that was my first thought - although I could hear the click and the readout said it was sending a call signal to the boiler. To be sure, I swapped out for a very basic thermostat and it seemed to work, but it was false hope. After the heating was turned off, it didn't come back on. When I attempt to turn just the heating on, the boiler doesn't fire and the circulation pump doesn't start.
I can make the heating come on by setting both heating and hot water on at the controller AND turning the tank stat up. The 3 way moves to M and the boiler fires and the circulation pump starts. If I turn the room stat down, the 3 way moves to W. If I then turn the room stat up, it moves to M (or H if the tank stat is at temperature) and the boiler continues running. During all of this, the circulation pump continues running as expected.
That's why I'm thinking that it's a sticking microswitch.
Have I missed anything else? And if I buy the actuator head, would that be the right part to change? (I'm not convinced I fancy taking it apart and soldering in just the microswitches I've bought from somewhere random on eBay).
Thanks for taking the time to read all of this.
First post; sorry it's so long, just trying to provide all of the information as I've spent a while diagnosing the problem already. My current theory is a sticking microswitch in the 3 way valve. I'm hoping someone can tell me if I could be on the right lines and if so, what I need to buy to fix it.
The boiler has been running every day to provide hot water, so I don't think it's anything catastrophic...
I have a very old Trianco oil boiler. There is a room stat and in the airing cupboard there is a hot water tank, a British Gas branded controller,a Grundfos pump and a Drayton MA1 3 way valve.
The boiler, and the pump definitely work and the lever on the 3 way valve moves the way I'd expect when I operate the controller. The room stat was a Tado and that was my first thought - although I could hear the click and the readout said it was sending a call signal to the boiler. To be sure, I swapped out for a very basic thermostat and it seemed to work, but it was false hope. After the heating was turned off, it didn't come back on. When I attempt to turn just the heating on, the boiler doesn't fire and the circulation pump doesn't start.
I can make the heating come on by setting both heating and hot water on at the controller AND turning the tank stat up. The 3 way moves to M and the boiler fires and the circulation pump starts. If I turn the room stat down, the 3 way moves to W. If I then turn the room stat up, it moves to M (or H if the tank stat is at temperature) and the boiler continues running. During all of this, the circulation pump continues running as expected.
That's why I'm thinking that it's a sticking microswitch.
Have I missed anything else? And if I buy the actuator head, would that be the right part to change? (I'm not convinced I fancy taking it apart and soldering in just the microswitches I've bought from somewhere random on eBay).
Thanks for taking the time to read all of this.