Central Heating taking two hours to warm up

[Smilin]

Hello,

I'm not a plumber, and may get some of the terminology wrong in this post, please don't shoot me down for it.

Since moving in to our home several years ago, we've had issues with the performance of our central heating. In winter, the living room can take up to two hours to get upto 18C from 15C in the morning.

History:
When we moved in, we had a heating engineer upgrade the system to S-Plan, and replace all TRV's in all rooms, remove the TRV's from the living room, and replace the heating controls.
a year later we noticed water flowing to the tank in the loft, the plumber extended the expansion vent pipe up higher in the loft space so the water had further to travel
Two years ago we had a new boiler installed as it was condemned by Cadent
Last year we noticed the issue where turning the pump up caused the water to flow up the expansion vent pipe again.
Since moving in, we've been gradually replacing the radiators, We now only have 1 radiator in the kitchen, and 1 in the spare bedroom to replace.

Observations:
If we put the pump on the highest setting the living room heats up quicker, but this causes water to flow up the expansion into the tank in the loft, and it ends up like sauna up there.
The tank in the loft doesn't overflow, suggesting the cold water feed if feeding into the system.
Looking at the pipework, it looks like the expansion vent is within 150mm of the cold water feed, and both are on the suction side of the pump.
I've attached photos of the pipework in the airing cupboard. A lot is hidden, but will hopefully give some insight

I have a suspicion about what's wrong, but wanted to see what the experts on here thought first.

Any suggestions?
James

 

[SJB060685]

And yet, some open vented systems like my own, almost 1/2 a century old have never given the slightest trouble, with some of the original rads, and only the odd drop of inhibitor thrown in.

All comes down to the installer, their understanding and the quality of the installation I suppose.
Once up and running most systems are pretty capable of looking after themselves but not always, there's a lot of variables to consider.

 

[John.g]

I reckon it helps a lot if its a combined vent and cold feed installed like mine right up at the F&E tank as there is no or little sludge up there.

 

[Smilin]

The images above suggest the pump is on the flow after vent and feed. The problem is most open vented systems are decades old and even if the orientation of vent fill and pump is correct from the start that is an awful long time for corrosion to occur. The management of system water quality and thorough expelling of air and dissolved gases is something that is really only been taken seriously in recent years.

I take it the upgrade to s-plan, the heating engineer wouldn't have changed the orientation or the pipework around the vent, feed, pump area? Just trying to get an idea of how long that pipework has been there. I think it has been replaced at some point as it no longer lines up with the pipe clips attached to the wall.

I may ask the plumber tomorrow to change it to a combined vent/feed arrangement.

 

[SJB060685]

No no changes would have been made.
You could ask the attending engineer to convert a combined feed and vent but if you have a blockage and it's where I suspect this would need to be cleared as well.

 

[exedon2]

I would seriously consider converting to sealed system lose header tank completely.

 

[Smilin]

After the boiler service, and a quick look in the loft, the magnaclean was in a state, and the header tank is not much better. Unfortunately the guy who services the boiler is booked up for 3 months now, so I'm having to find someone else.

 

[SJB060685]

Based on the above I recommend finding a decent engineer who could do a thorough powerflush and possibly redo the pipework as mentioned previously. A flush might be all that's needed.

 

[John.g]

After the boiler service, and a quick look in the loft, the magnaclean was in a state, and the header tank is not much better. Unfortunately the guy who services the boiler is booked up for 3 months now, so I'm having to find someone else.

Cut a bit off that vent pipe as well, it shouldn' be dipping in the water.