Why oh why little bungalow…

[Piedpiper]

What are the flow and return from the boiler like? What is the temperature difference between the flow out of it and the return back to it?

Me again…Do you mean whilst the boiler is running or once it shuts off? I just got to it as it shut off and it was around a 40° difference between the two, it’s been around 10-15 mins and it’s just sparked up again at around 16-16° difference.

 

[Piedpiper]

Heats up the supply to about 77° then shuts off, at that point I check the difference and it’s about 37-39° difference this time. No idea if that’s any good or not.

 

[Chuck]

Check the easy stuff first. Does the expansion tank has an appropriate amount of water and is its float valve working okay? Next, bleed the radiators to get all the 'air' out of the system.

 

[Piedpiper]

Check the easy stuff first. Does the expansion tank has an appropriate amount of water and is its float valve working okay? Next, bleed the radiators to get all the 'air' out of the system.

Hi Chuck, thanks for your reply mate, I’ve checked the expansion system up in the loft, level looks ok and the system adds more water in if I press on the arm, all radiators are bled up as well buddy.

 

[Chuck]

I’ve checked the expansion system up in the loft, level looks ok and the system adds more water in if I press on the arm, all radiators are bled up as well buddy.

As it's a vented system, the pipes may be getting clogged up with sludge. Check the copper pipework with a magnet. If there is a significant amount of sludge (magnetite) inside the magnet will be attracted to it. A sludged-up system will normally have brown 'rust' in the expansion tank.

 

[Piedpiper]

As it's a vented system, the pipes may be getting clogged up with sludge. Check the copper pipework with a magnet. If there is a significant amount of sludge (magnetite) inside the magnet will be attracted to it. A sludged-up system will normally have brown 'rust' in the expansion tank.

This is something that I think may be an issue, the tank itself is relatively clean, but as for the age and servicing of the system, whether it’s had cleaner or inhibitor put through it at any point is a mystery, I was considering having someone out to do a power flush on the whole system so I can start fresh and if after that I find it’s a component issue then at least the condition of the whole system can be taken off the suspect list.

 

[dave176]

This is something that I think may be an issue, the tank itself is relatively clean, but as for the age and servicing of the system, whether it’s had cleaner or inhibitor put through it at any point is a mystery, I was considering having someone out to do a power flush on the whole system so I can start fresh and if after that I find it’s a component issue then at least the condition of the whole system can be taken off the suspect list.

If it's an old system then I'd go for a powerflush and possibly a new circulation pump. I've worked on many systems and I've yet to find one that hasn't benefited from a powerflush. Only problem with this is that some people charge extortionate prices for a powerflush. I recently had a customer who paid €800 to get 9 radiators powerflushed and the system was left unbalanced. That's a criminally insane amount for just 9 rads.

 

[Piedpiper]

£800?!? Chuffing Norah I hope it’s nowhere near that! I just can’t seem to make any sense of the system, I can get all of the rads warm, to about 40°, but the only one that gets mega hot is the first one in the bathroom, and when I get the others warm in one room it’s at the cost of another rad in a different room going cold.

What exactly is the purpose of checking the different temperatures of the flow and return to the boiler? Is it to see whether the boiler is shutting off before it’s managed to allow enough time to pass to send hot water to all the rads? If that’s the case would that show that the returns are opened up too far across the whole system allowing the hot water to return quicker to the boiler than it should do?

 

[dave176]

£800?!? Chuffing Norah I hope it’s nowhere near that! I just can’t seem to make any sense of the system, I can get all of the rads warm, to about 40°, but the only one that gets mega hot is the first one in the bathroom, and when I get the others warm in one room it’s at the cost of another rad in a different room going cold.

What exactly is the purpose of checking the different temperatures of the flow and return to the boiler? Is it to see whether the boiler is shutting off before it’s managed to allow enough time to pass to send hot water to all the rads? If that’s the case would that show that the returns are opened up too far across the whole system allowing the hot water to return quicker to the boiler than it should do?

heat loss and efficiency would be the main reason but I'm sure others have different options. the same with balancing the system, some say just balance the flow others say balance flow and return though Danfoss have come out with a new TRV that say leave the return fully open, they even have an app for setting the TRV to the size of the radiators.
All that being said, it sounds to me like you either have a flow issue or the boiler is too small for the system but I don't know what boiler you have or how many radiators you're running. if you're handy with your hands try locking down the smallest radiator in the house and drain it down then take it outside and flush it out with a hose. if there's a lot of sludge in the system you'll know by doing that or like another person said try a magnet on the pipe work. if you do take a rad off and flush with a hose it won't help your problem, I'm only suggesting it so you can see if there's much black iron oxide in the system

 

[Piedpiper]

Cheers Dave, when bleeding the rads in the first place the water was quite murky in places. I’ll have to bite the bullet I think and shop around for a reasonably priced power flush!