Airlock in the cylinder coil of my Evinox (RC15) boiler - How can I release it please?

26 Nov 2018
Reaction score
United Kingdom
Hi, I've an Evinox Heat Meter Mod RC15 Boiler.

I had a cold spot on a radiator and bled it. The boiler pressure dropped to 0.5bar. A red warning light came on on the boiler as well as on the wall mounted 'viewsmart' controller.

I refilled the boiler back to 1.5bar. The warning light on the controller went out but not the one on the boiler.

I made no other changes but now neither the heating or the hot water are working.

There is a steady green light on for the (Wilo) pump (i.e. its working fine). There are no noises or gurgles. The cold water runs fine.

I also have an immersion tank. If I switch the immersion on then the hot water and heating work fine. Hence I think the problem is boiler related.

I spoke with Evinox and sent them the system read-out from the viewsmart controller. They said the readings were fine and they think the problem is an 'airlock in the coil in the cylinder'.

I have now bled every radiators and both towel rails - and had no success with that.

I cannot see any other vents on the boiler. So can see no way to vent the airlock out of the cylinder coil / system.

I have read the following two online comments advising to:

- "crack open the nut on the return until water flows. careful not to flood the house"


- "prevent the boiler firing and then start and stop the pump a few times until it cleared the air. much less messy."

I am not sure if either of the above comments are the right way to proceed. And if so I am not sure how to do either of them.

So I'd appreciate any advice on the above ideas or any new ideas to help me release the airlock please?

Thank You,

Ps. happy to send photos or skype if anyone has the time please
Sponsored Links

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local