Biasi m96.28cm/c leak from pump air purge valve then diverter

[_Mr_A_]

Hi any guidance appreciated as my regular plumber is currently unavailable and as I'm having to call in a new one. Any info would be greatly appreciated to help when discussing this with them. I wouldn't usually but as a few I've called are mentioning a new boiler given the age before coming out a sanity check would be appreciated.

My Biasi m96.28sm/c combi boiler (at least 14 years old) developed a leak from the pumps air purge valve (part BI1212107). This was a weep\drip that would happen for a short period then reach an equilibrium and stop, often stopping for months at a time. This has been happening for approx 1 year. If a radiator was bled the drip would start again and often if a lot of air was bled the leak would be more significant. It would however always stop I presume once the system reached a balance. Note Radiators were only being bled where a radiator was cold at the top and the leak had slipped my mind.

The pumps air purge valve was replaced and whilst this prevented the leak from the purge valve, the same behaviour is now exhibited from the diverter valve, with the leak coming from where the actuator connects.

I cannot confirm the pressure of the central heating system as the pressure valve has always been stuck at 0.7'ish regardless of the system being emptied, filled, bled etc..

The central heating and hot water work on demand. There are no error codes being displayed and the only issue this appears to cause are the occasional weep\leak from the diverter once it has settled (originally the pumps air purge valve)

Also noticed in case it helps
1. A single radiator heats up slightly when running hot water to the shower (this may have happened prior to the leak)
2. There is air in the system as the bathroom radiator (highest point) only heats half way up the vertical height of the rad.

It would appear that the system has an issue with pressure and the weakest point currently is the diverter.

Does this sound like a fault that could be repaired or is it likely not worth the cost in man hours to swap out parts?

Thanks
A.

 

[ianmcd]

Of course the diverter valve can be repaired, very common fault, if you say where in the country you are possibly someone on here can either help you out or recommend someone that covers your area, hardly a big job, and the rad not heating at the top simply needs bleeding and your pressure guage is blocked

 

[MeldrewsMate]

As it's a sealed system the 'air' you bleed may well be by-products of corrosion. You also seem to be describing a dirty system (the main reason your auto air vent wasn't shutting properly, and why your gauge fails to register corectly.

A flush and clean is possibly the way out of this mess, and this doesn't have to be a power flush. Something like Sentinel X400 may clean your system, followed by X100 inhibitor.
Also consider fitting a magnetic strainer to the system.

The leak from your diverter, as you described it, seems to be of fresh water, not heating system water. This can be repaired easily and cheaply.

 

[_Mr_A_]

Thanks for the reply, I was concerned with the leak moving from the pumps air purge valve to the diverter and that this might indicate a larger issue just being exposed via these 2 locations. The property is in mid-suffolk.

With a faulty pressure gauge I assume this is likely a blocked pitot tube or at least that should be cleared before replacing?

 

[ianmcd]

The leak from your diverter, as you described it, seems to be of fresh water, not heating system water.

There is no "fresh water" in this diverter valve