CH Not triggering Boiler - started today.
OK This may be another version of other peoples questions on here, but I wanted to ask as my setup seems slightly different.
I have had my entire setup for almost 3 years, working fine, this just started happening today.
My setup consists of a Wired Thermostat, and 7 TRVs. No Hot Water Extension.
My system (non-Tado) 'brain' has the CH set to ON (so that Tado can control it) and the HW set to timed. When I went to bed last night (about 12:20am), my bedroom radiator was on and set to turn off at 1am. My HW is set to turn off at 10pm, meaning the CH WAS working independently.
Today, I noticed that none of my radiators were hot. My office TRV said is was 18 and it was heating to 20, but the radiator was cold. I went into the spare bedroom, stone cold radiator (as always set to FP) cranked the TRV up to 25, nothing, checked the boiler, off. I went to the 'brain' and turned ON the hot water (it was timed to come on later) and the boiler fired up, and the radiators started to heat up. However, once the water tank was full of hot water, the boiler turned off, and the radiators started to cool down again.
I have tried turning up the wired thermostat, same thing, no response from boiler.
I am trying to figure out if this is a Tado issue, or a physical issue with the heating system (3-way Valve?? - I keep hearing that mentioned in forums)
Any help/advice/suggestions would be appreciated. Really don't want to have to explain to the wife later why the 'smart' heating isn't working and my toddler needs to wear 5 layers.
TiA
Answers
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If yours is a Y plan system it sounds as though you might have a problem with the mid position valve. If you have a multimeter you could check whether power is reaching the latter when the tadoº thermostat calls for heat . . .
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Thanks for your reply, although not entirely sure what Y plan (or mid-position vale) is exactly... I do have a multi-meter though lol
Does a Y plan mean it uses a 3-way valve, I THINK mine actually has two 2-way valves, but not 100% sure.
UPDATE - I just checked and yes mine appears to have two 2-way Honeywell valves.
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If you have two Honeywell two-way valves for HW and CH, that's an S-Plan. From your symptoms, I'd be highly suspicious of the zone valves. These can fail (e.g. sieze or burn out the motor) anytime from less than 1 year to 20 years. Murphys Law says that both valves are the same age and will fail at the same time.
To check if they are working: the valve motor head has a manual control lever on the end of the grey? box on top. Using your thumb, move the lever to the right as you look at it. Is there is resistance? Or does it move very easily to the right?
If there is resistance moving the lever to the right, the valve should open, close the microswitch and call the boiler for heat. If the lever is easy to move, the valve is open and should already be calling the boiler for heat. When Tado stops calling for heat, the valve should close and the lever should return smoothly to the left 'OFF' position.
Since you have two valves, you can compare how HW and CH valves behave to see if one is faulty.
HTH.
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