At my wits end with this heating system PLEASE HELP!

[iateyoubutler]

Evening all

Basically, this system is doing my head in. It`s 40+ years old, and when I bought this house a few years ago it had the original Ideal Concord boiler fitted down in the kitchen, feeding this lot in the pictures, plus 7 radiators. All was fine, it was faultless.

I decided to have the boiler updated so had a Vaillant Ecotec 415 fitted, everything else remained the same. That is when the problems started. If I use the central heating by itself there are no problems, it works really well. Now, if I go to hot water only it will start out quiet, and then once the boiler fires up the pump will begin to drag air through, and this gets louder, and louder until the pump is almost struggling for water. All the while the coil in the cylinder is gurgling like hell. It will behave like this until the water is up to temperature, or I lose my rag because of the noise and turn it all off.

The strange thing here is, if I switch the boiler thermostat off and run the hot water circuit (so just the pump), there is no noise/air/gurgling etc, it is only when it`s being heated. So is the boiler creating gases in the water? Or a chemical reaction going on?

It is doing my head in, even to the point now where I find it less agro to just use the immersion heater instead.

I`ve put some photos up, they are a bit dark so apologies, so can anybody see any problems with the layout etc?

I would love to sort this, as it`s turning into a battle of wits between the heating and me now, and I`m going to win!!

Thanks

Read more: https://www.diynot.com/diy/threads/...ting-system-please-help.544102/#ixzz6LDYtzd7F

 

[CBW]

Evening.

(Think you may need to provide more than two words and a couple of photos)

 

[iateyoubutler]

This decided to upload itself before I was ready...........

 

[iateyoubutler]

Evening.

(Think you may need to provide more than two words and a couple of photos)

Yes I got a bit click happy before I finished typing!

 

[CBW]

I’m not 100% sure but it might be because you now have x2 pumps? Is the boiler lower down, eg in the kitchen?

 

[iateyoubutler]

I’m not 100% sure but it might be because you now have x2 pumps? Is the boiler lower down, eg in the kitchen?

Hi Chris, no my boiler is heat only, the pump in the picture is the only one in the system. The boiler is pretty much below what you can see in the photos

 

[Hugh Jaleak]

Have to wonder if the pipework setup isn't helping matters, looking at it, it seems to be open vented. (Vent and cold feed below the pump?) Personally would have piped it with the H configuration, putting the pump below the vent and cold feed so any air goes straight up the vent, and then 22mm on the return as well with a gate valve to control the HW flow, gives you some adjustment of flow rates. Also then avoids the need to an air vent on the coil, which may be part of the issue, trapped air.

Definitely only the boiler that was changed, no pipework alterations in the cylinder cupboard?

 

[iateyoubutler]

Have to wonder if the pipework setup isn't helping matters, looking at it, it seems to be open vented. (Vent and cold feed below the pump?) Personally would have piped it with the H configuration, putting the pump below the vent and cold feed so any air goes straight up the vent, and then 22mm on the return as well with a gate valve to control the HW flow, gives you some adjustment of flow rates. Also then avoids the need to an air vent on the coil, which may be part of the issue, trapped air.

Definitely only the boiler that was changed, no pipework alterations in the cylinder cupboard?

Thanks Hugh. Yes it is open vented, a traditional system with large and small roof tanks. When the boiler was fitted it was literally a straight swap, and I had the roof tanks replaced with new as I didn`t trust the old ones. Everything else has stayed exactly the same

 

[Hugh Jaleak]

I'm not an expert on the Vaillant boilers, only thing I do wonder is if it is putting heat into the water faster than the Ideal did, and the system is struggling to dissipate that heat into the cylinder quickly enough. It'll need someone more knowledgeable to advise further though, sorry.

 

[iateyoubutler]

I'm not an expert on the Vaillant boilers, only thing I do wonder is if it is putting heat into the water faster than the Ideal did, and the system is struggling to dissipate that heat into the cylinder quickly enough. It'll need someone more knowledgeable to advise further though, sorry.

So do you think the 15mm pipe on the outlet of the cylinder coil could cause it? Maybe? Just clutching at straws.....

 

[Hugh Jaleak]

Some used to pipe the return in 15mm to restrict the flow through the cylinder, and avoid the central heating getting starved of flow when both HW and CH were calling. My preference has always been to do it all in 22mm, then fit a valve on the return to allow manual adjustment and reduce any possible noise.

I'm not convinced that would be the issue though, my main concern would be with the layout of the pipework below the pump. The better solution is the 'H' setup, so as an example, bottom left feed from boiler, top left vent, top right cold feed and bottom right flow to motorised valve(s).

 

[iateyoubutler]

Some used to pipe the return in 15mm to restrict the flow through the cylinder, and avoid the central heating getting starved of flow when both HW and CH were calling. My preference has always been to do it all in 22mm, then fit a valve on the return to allow manual adjustment and reduce any possible noise.

I'm not convinced that would be the issue though, my main concern would be with the layout of the pipework below the pump. The better solution is the 'H' setup, so as an example, bottom left feed from boiler, top left vent, top right cold feed and bottom right flow to motorised valve(s).

Many thanks for that info, I`ll get that done when I can, or even have a go at it myself over the summer. I`ve always wanted to teach myself to solder so this could be the ideal chance!

To be honest there`s nothing to lose now, if this doesn`t sort it the whole lot is coming out and started again from scratch

 

[Hugh Jaleak]

If your new to soldering, watch some video's on how to do it first. Get yourself a decent blowlamp, (Rothenberger aren't cheap but they are good!), and take your time. Again, Yorkshire fittings are more expensive, but are almost guaranteed not to leak provided care has been taken soldering. Cleanliness is next to godliness, and use a decent heat mat to protect surrounding surfaces.

Lastly, if there is any water left in the pipe, it will not solder, not matter how much heat you put on it!

 

[Nige F]

Is the air bottle / auto vent working properly ? it's the only place for air to escape the coil

 

[iateyoubutler]

Cheers again for the advice Hugh. I`m sat down now with pen and paper trying to work out how the lay out H frame in my airing cupboard. I`m always soldering cable, so soldering isn`t totally alien to me, obviously pipes are just a larger scale. I certainly will make sure everything is dry, I`m going to drain the system down and take my time with this project, if it takes all of the summer (which it shouldn`t!) then so be it, as long as I get it right