Danfoss TS715SI not working?

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Hi there,

All of a sudden I have no hot water. My system is a Baxi Megaflow combo boiler with a Unicyl hot water tank. I have a Danfoss TS715SI panel with an ESI thermostat fitted to the tank.

I’m trying to get to the bottom of the issue, which I initially thought was the ESI thermostat, but having replaced that, it’s we still have not hot water. The ESI thermostat shows no digits or temperature on the lcd display, but neither does the Danfoss TS715SI. The red light is on on the Danfoss, however it’s jammed on and I can’t change any settings. I’ve enclosed pictures of both the Danfoss and ESI. Anyone see the route of the issue? Should the Danfoss be displaying on the lcd screen and not be blank?

I’ve also enclosed a picture of the water heater switch which heats an element within the tank. I’m assuming that this switch should be off In general?
 

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Yes the immersion switch is generally off, unless you want hot water electrically heated, but if you’ve no hot water I’d say it’s off anyway, could be wired wrong for the neon to be on. The danfoss - does definitely do the hot water? If yes, check the batteries, iirc most of those types do. Next port of call might be the motorised valve, but unsure why the cylinder thermostat isn’t lighting up, unless it’s via the switch live of the mv.
 
To be honest, I’m unsure if the Danfoss does hit water. Could that just be the main control point for these (pic enclosed). Still odd that the thermostat fitted to the water tank isn’t showing any signs of power.
 

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Yes the immersion switch is generally off, unless you want hot water electrically heated, but if you’ve no hot water I’d say it’s off anyway, could be wired wrong for the neon to be on. The danfoss - does definitely do the hot water? If yes, check the batteries, iirc most of those types do. Next port of call might be the motorised valve, but unsure why the cylinder thermostat isn’t lighting up, unless it’s via the switch live of the mv.
Is there any way to check if the motorised valve is working?
 
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Is there any way to check if the motorised valve is working?
Here’s a photo of the valve. Looks like the wire going in is pulled downward - could be a loose connection?
 

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Is there any way to check if the motorised valve is working?
With no requests for heating or hot water, try moving the lever on the valve for hot water. You have x3 valves btw.
 
The central heating is working fine. It’s only hot water that’s the issue. I’ve moved the switch to manual and jammed it on for the valve shown. Yes there are 2 valves that look different from this one below.
 
No don’t jam it open, see if it’s loose at all. If not, then the microswitch might not be making.
 
There’s definitely still tension on all of the switches. When I push them, they return to position with the usual noise.
 
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Have you done any electrical work recently ? looks like you have reversed polarity, smart meter fitted recently by any chance ?
 
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No smart meter fitted, however the hot water did stop working in the same day as I fixed my daughters light. I just changed the rose fitting but had to turn the electrics off at the mains. It hasn’t worked since it turned the mains back on.

Could that have caused an issue?
 
No smart meter fitted, however the hot water did stop working in the same day as I fixed my daughters light. I just changed the rose fitting but had to turn the electrics off at the mains. It hasn’t worked since it turned the mains back on.

Could that have caused an issue?
yes it could, take a pic on your phone of the wires in the ceiling rose so you can put it back together correctly if that is not the fault, then disconnect the wires and isolate/seperate them, then see if your heating controls come back to life , the colours of the wires in your lighting dont mean anything so mark which wire is which
 
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I’ll give that a go when I get home, thank you. It does seem too much of a coincidence. I’ll let you know if that works!
 

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