Megaflow valve leaking

[oilman]

Yes the black plastic cap is missing, is that the cause of the leak?

The cause of the leak is that the valve has failed. The black cap is just so as you can get over problems like this and use it as a manual valve.

We are not alone

Good. How are you at weilding a spanner?

Look here and scan down to "Air vent - Robocol". Part no. 17842 looks like yours. Don't go for the cheaper one, it will not fit as a replacement.

Your system has a red expansion vessel somewhere, and near that is a pressure relief valve. It may be in the boiler. What boiler do you have?

Open the pressure relief valve (usually turn anti clockwise) and reduce the pressure to zero.

Have the new valve ready (take it's nut off), and undo the nut under your existing one. Take it off and shove the new one on, you won't lose much water. Then do up the nut. Or use your local handyman. A plumber is not needed.

If you spend £45 with them, you may not get a carriage charge.

Before you increase the pressure, Take the cap off the air valve on the expansion vessel, and check the air pressure is about 1 bar (14psi) if necessary use a foot pump (or a bicycle pump). Once the air pressure is right, increase the water pressure to around 1 bar as well.

 

[Agile]

Yes the black plastic cap is missing, is that the cause of the leak?
What is an AAV or AVV valve? What does it do?

See Monty Halls' living his dream BBC2 9.00pm tomorrow night BBC2. The real reality is we don't have a plumber within 80 miles and we pay 4 hours travel before they start the job.

Thank you all for your help it makes a big difference to know
We are not alone
Avril

Replacing the AAV is only classified as a DIY job which any competent DIYer could do themselves.

Unfortunately, to support an independent plumber, there needs to be a population of about 500 or more. But thats now distorted by the BG and other insurance based schemes so an independent plumber would probably need about 1000 or more. Thats if he wanted and could afford to live there.

Tony