Possible Blocked Return Pipe

StvPL · 29 Dec 2009

Hi

I have an open vented system with 18 radiators + 20sqm or so of underfloor heating (never used). It has 10mm plastic pipe upstairs and 10mm copper downstairs feeding the radiators (powered by a grundfos 15/60).

I've had a problems which has been getting progessively worse where the radiators are not getting that hot in some of the rooms (mainly upstairs). They are generally cool at the bottom and the radiator return is also cool.

If I turn off the radiators that get hot the pump starts groaning and the flow pipe from the boiler stays red hot while the return starts getting cool.

I've ordered a couple of bottles of X400 and a magnaclean which I intend on installing very soon.

My question is... am I going about this the right way or is there anything else that could be causing the problem? Also, is there anything else I can try? I was looking at the mains flush as a plan b.

Thanks in advance

Steven

joshmcfee · 29 Dec 2009

Powerflush the system//You'll be wasting money with Sentinel and your Magnaclean will only be effective on a clean system//

Happyplumber · 29 Dec 2009

personally on system like this i would use 2 bottles of x800 which is a bit more aggresive then x400

get it into the system and let it run hot for at least 8 hours and then drain down and flush through

GodKnows · 29 Dec 2009

Hi all,

Does your boiler (No info on which one!) shut down when the flow pipe gets hot? What temperature setting do you have on the boiler? Do you have a room stat fitted? Or run off boiler stat? The pump needs to be checked! If the problem is progressively getting worse, then, the pump cam be failing. Need about 180 Ohms on the pump

StvPL · 29 Dec 2009

Powflush is definitely a possibility but I thought a Magnaclean would be a good investment for future protection should it not help solve my problem.

I did look into X800 too, my only fear was not being able to empty the system completely after running it. Maybe not an issue if I run enough water through?

StvPL · 29 Dec 2009

GodKnows said:
Hi all,

Does your boiler (No info on which one!) shut down when the flow pipe gets hot? What temperature setting do you have on the boiler? Do you have a room stat fitted? Or run off boiler stat? The pump needs to be checked! If the problem is progressively getting worse, then, the pump cam be failing. Need about 180 Ohms on the pump

Hi. The boiler is a Trianco Oil 70/90. It does seem to switch on and off as needed. There is no temp settings but the dial is set to about half past 6! I do have a room stat which is in a room with a working rad, hence the system switching off when that rooms warm but others struggle to get above 17 deg. Even if I turn the rad down near the stat the cold rooms don't get above 19.

I know without testing there is no way to know if the pump is working properly but it does seem okay, though there is often a rushing water sound through it like theres not enough water (same with one of the rads downstairs that occasionally gurgles when heating switches on).

Whats the 180 ohms bit mean?

GodKnows · 29 Dec 2009

Hi all,

The Ohms test is for the pump, approx you need 180 across Live and Neutral to test the pump

Turn rad down in the room where stat is and crank up the temp on the boiler

Remember, the outside temperature of late is colder than normal, therefore, you need to adjust the output of the boiler! i.e. turn it up fella

StvPL · 2 Jan 2010

Thanks for your help.

I've managed to test the resistance with my multimeter across the cable terminal with the cable disconnected. Across live/neutral to earth was infinity and across live to neutral was: 208 ohm for speed 3, 352 ohm for speed 2 and 417 ohm for speed 1.

Do these sound normal?

Thanks

GodKnows · 2 Jan 2010

Hi all,

Yeap

pump ok, if you want to check drain down, and see if back of pump free from debris. Also, check condition of water in system fella...

StvPL · 2 Jan 2010

Thanks again

Just drained one of the rads and the water was very very black with lots of particulate matter. I checked the flow on the return pipe while it was off. At 2 turns the the water was flowing out fairly fast but at 4 turns it had almost stopped again, not sure if this means anything?

I think it's time to call in the powerflushers, any idea how much I should expect to pay?

Cheers

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Possible Blocked Return Pipe

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