Frequently Asked Questions

How do I find out the size of my radiator tapping?

With a 1/2" BSP thread, the threaded hole in the tapping at the top of the radiator is approximately 20mm diameter – you should be able to fit your index finger in the tapping. The plug screwed in to the tapping will either be a chrome hexagonal valve, or a 'plug' with a square cavity in it.

A 5mm radiator tapping is easy to tell as it is much smaller - 5mm!

Most cast-iron radiator tappings are 1 1/4" BSP – about 40mm diameter (if this is the case please contact us – you will require an adaptor).

Please Note

The Aladdin H50 valve only fits 1/2" BSP radiator tappings. See ‘coming soon’ for the 5mm type tapping (for roll-top radiators).

Can I fit the Auto Vent (AAV) to a new system?

With one AAV fitted to each radiator significant amounts of time can be saved on installation by eliminating the need to visit each radiator as they close when full of water. We still recommend a final visual inspection to check for system joint leaks, but next-day, or next-week visit to bleed the radiators will be unnecessary.

Does the AAV work on Closed and Open systems?

Yes, on newly installed closed systems there will be a small pressure drop (around 15%) as the air is vented from the fresh water, but any further pressure drop will be due to loss of system water (leaks). Some installers are priming a newly installed system to about 10% more than it’s operating pressure to compensate on a system fitted with AAV’s. “ On a Closed system will fitting automatic vents cause the pressure to drop to zero and the boiler stop operating?”

The answer is linked to the above – continual venting will be due to new air entering the system (through microgaps in joints etc), once the fresh water has vented its 15% of air the volume of water cannot further reduce in size – so if you still experience pressure drop it’s due to water loss.

Can corrossion inhibitors be used with an AAV?

Yes, fitting the AAV should reduce the need for corrosion inhibitors as all your radiators will be free of air, but we do recommend their use because corrosion leads to further air being deposited in the radiators. To allow inhibitors to be used ensure at least one radiator.

still has a manual vent plug fitted at the opposite end to an AAV, as this will allow the inhibitor to be injected.

Can leak-stop products be used with the AAV?Leak-stop products can jam valves in certain circumstances. We do not recommend their use.

What if the AAV is not venting?

Because the valve operates on temperature fluctuation central heating systems fitted with a timer (so they switch on and off), room thermostats, or Thermostatic Radiator Valves on the radiators will experience temperature fluctuation and so the AAV’s will vent.

A minority of systems with none of the above and operating continously at thesame temperature (eg hospitals and hotels) may not vent until the water level drops by about 1/3rd, if this is not desirable use the manual vent facility (see below).

Ensure Thermostat Radiator Valves are turned to at least level 2.5 in order for the AAV to operate efficiently. We recommend that the valve is fitted to the flow (hotter) side of the radiator.

Can I vent the AAV Manually?

Running the radiators continually ‘cool’ may not trigger the AAV operating temperature and lead to a gradual build up of air in the radiators. To test, use a ball-point pen to gently press and release the pin in the middle of the white Safety Cap (when the radiators are cold) – this will override the automatic vent and cause a vent to occur if air is present.

This indicates that if TRV’s are fitted the temperature setting should be higher in order to operate the AAV.

Can I fit the valve to a piping ‘spur’ at a system high - point?

Yes, provided the temperature of the piping allows the valve to operate at 47°C.

DONT’S

Don’t cover the valve with wet items (this causes temporary shut-off).

Don’t paint over the valve.

Please email us with your comments and queries: support@autovents.net