Honeywell Smartfit NOT heating HW

[hesley67]

My Honeywell smartfit system has stopped heating the water up. Over the weekend I drained my CH system with a view to flushing it out. I isolated the boiler, (turned off the power) and drained my CH system. I added the cleaner to the expansion tank and refilled the system. My CH works perfectly and actuator on top of the pump seems to be working fine but when I set the room controller for HW only the boiler doesn't light but the room controller shows the boiler is lit. If I set the room controller to CH the boiler lights and rads get warm. It seems as though I need to reset my system but am unclear on how to do this.

Also there are no fault codes shown on my room controller

 

[stem]

If the boiler 'on' light is present when hot water only is selected and the valve is positioning itself correctly, it sounds as if all is well with the controls and the fault may be elsewhere.

When you refilled the system you may have introduced an airlock in the hot water part of the circuit which is preventing hot water from the boiler reaching the hot water cylinder. In this case, when hot water only is selected, the boiler remains filled with hot water from heating the radiators, that is not going anywhere, so it won't cool and so therefore the boiler won't fire up.

However, it is possible that the switched live from the controls may not be actually getting to the boiler. You can check that the boiler is actually getting a live supply when just the hot water is on, if you have a multimeter and know how to use it. This will then confirm if the problem is with the controls or not.

 

[hesley67]

How would I remove an airlock from the HW side

 

[stem]

That all depends on how the system was designed and installed. There should be a vent, or a bleed nipple somewhere. Look along the pipe between the motorised valve and the hot water cylinder.

Here's an example.

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• stem
• 13 Apr 2015
• 1

and another

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• stem
• 13 Apr 2015
• 1

 

[hesley67]

Thanks for the reply stem. It's all sorted now thanks. It was an airlock in the system. I bled my invented cylinder and to make sure I also opened up all the taps. Boiler now fires up and thankfully heats the water up. At least I know what to do when I flush out the cleaner next weekend, fingers crossed

 

[stem]

Good, glad it's sorted.

Opening the taps will not have any effect. The two water systems are kept separate. That is why there are two feed and expansion tanks. Otherwise you would be bathing and washing your pots in water containing the cleaner you've added.