Air in ferroli boiler

[sxturbo]

Hi everyone,

I have a ferroli domicondense HC 26, I know it's not the most reliable or best boiler, and we have had our fair share of problems with it and would love to replace it but at present it's not really possible.

Any way, there seems to be air in the boiler, when the central heating switches on in the morning and then switches itself off there is a gurgling noise heard within it. I know it is trapped air.

I'm not sure how the trapped air got in as it wasn't there before the summer and the heating has been off until now. We have had homeserve come out to look at it yesterday, the guy confirmed it was just trapped air, however he said there was a partial blockage in one of the pipes as the radiators took longer than 10 minutes to heat up and therefore there was nothing he could do, and recommended we purchase a new boiler to get it fixed or just put up with it until the boiler dies and being a ferroli it probably won't be long.

I'm not entirely convinced of this response and I'm sure there must be another way, however although I am very good at DIY and have replaced the odd radiator here and there, I'm not really all that with central heating boilers and what all the valves etc do at the bottom. If anyone can help would be most appreciated.

Sorry for the long post.

 

[muggles]

Your trapped air, if that is what it is, may in fact be hydrogen which is a product of corrosion (iron + water => iron oxide + hydrogen).

A partial blockage due to corrosion could be cleared by powerflushing, which should be done before/when you get a new boiler anyway, so that might well be a good place to start

 

[sxturbo]

Thanks. I'm pretty sure it's trapped air, it certainly sounds like it, sounds like bubbles popping to the surface when you insert an empty bottle in a sink full of water.

I can't really afford to replace the boiler just yet, I have a new born and wife is on maternity, and funds are a little tight.

When the boiler was installed 3 years ago the system was flushed and fernox was installed at the same time. (Boiler was fitted just before we moved in by previous owner and we have the reciept)

I need the boiler to last me at least another year, I was hoping to knock the kitchen and dining room into one and replace the kitchen and move the radiators around and am planning on putting a new boiler in then, but this won't happen for a few years yet.

 

[ianmcd]

unlikely to be air in the boiler as it has an automatic air vent to remove any air in the boiler, I would be looking to make sure the condensate trap is clear and not water backing up in the recuperator

 

[sxturbo]

The engineer did say about the condensate pipe but checked it was clear and was fine.​

 

[sxturbo]

So I have located the condensate trap, can I just remove and clean it?

 

[ianmcd]

yes you will know if it is blocked , make sure you have a bucket or bowl underneath as if it is indeed blocked there will be some water will come out

 

[sxturbo]

Hi everyone.

Thanks for your help. I cannot find any fault with the boiler, I have run the heating for a good couple of hours and there seems to be no further air in the boiler.

I have gone round and re-balanced the all the radiators, the downstairs radiators seem to get hot much quicker than the ones upstairs.

I now have the downstairs radiators working (hall, dining room, bathroom and lounge window), they get silly hot, except the 2nd radiator in the lounge, this doesn't get hot at all, I think all the downstairs rads utilise the original heating pip s, and the 2nd lounge was an add on when the house was extended.

The rad in the bathroom and the baby room get hot, (not quite as hot as downstairs), but the rad in the main bedroom which is closest to the boiler, gets hot at the top only.

I have bled the radiators. All the rads downstairs the valves are only just open, if I close them any more I get a loud hissing from the water trying to pass through such a narrow gap in the valves.

When bleeding the rads the water was perfectly clear, no sludge build up, just slight discoloration from the fernox.

I can here a hissing in the pipes when the heating is on, but so far cannot seem to pinpoint where this is coming from.

We have always had issues with the 2nd rad in the lounge, and I managed to get it sorted in the beginning of the year by balancing the rads. But after being dormant for the summer something has changed, not sure what.

Completely at a loss with this. Sorry for the long post.