Vented Heating System - CH but no DHW - Airlock or Valve?

[ukal]

Hi All,

I realise there are several other posts on here re this issue and I have read through alot of them to troubleshoot my problem but to no joy. I wondered if anyone could help please - I am new to all of this btw!

We have a gas boiler and CH, but no DHW.

Some info:
1) Cold water flows out of hot taps.
2) Boiler and programmer are working fine.
3) Myson Pump is working fine.
4) Potterton Myson Valve has lights on it for CH & DHW.
5) Electric Element on Immersion tank works fine.
6) With Water only setting on programmer - both DHW & CH pipes from valve are hot **
7)All radiators in house appear to come on and are controlled by the Water only setting on the programmer? The Heating setting is redundant?
8) We had a small leak in the bottom coil pipe from the tank - bu tightening up a valve tap that was attached has stopped this.

** However, the bottom coil pipe coming out of the tank appears cold and the top coil pipe going into the tank is hot directly coming out of the valve BUT it then makes an upwards 90 degree 'U' bend (with what looks like a bleed cap at the top of the U bend) before going into the tank - this section after the bend is cold, and is cold going into tank.

Reading this thread:

//www.diynot.com/forums/viewtopic.php?t=206453

I tried to bleed the radiator by "unscrew with a large screwdriver, only about a quarter turn" but this is too difficult to turn even with full strength - extremely stuck when turning anti-clockwise so I presumed it shouldnt be turned and so I left it! I do not appear to have an 'auto air vent' either as stated in the above thread.

Does it sound like an airlock problem (if so how do I bleed the system) or a valve issue?

Does anyone have any troubleshooting tips please? Will check forum as often as poss.

Thanks in advance!

 

[seco services]

BUT it then makes an upwards 90 degree 'U' bend (with what looks like a bleed cap at the top of the U bend) before going into the tank - this section after the bend is cold, and is cold going into tank.

Have you tried bleeding the air vent ?

 

[ukal]

Hi. Yes I've tried to turn that cap but its as though its seized up as its too difficult to turn. Will this definately be the bleed cap cos if so I'm sure I can open it with brut force but didn't want to if not? Cheers

 

[ukal]

I've tried that cap again and it wont budge - worried I'm going to break something if I turn it any harder!. Any other ideas on how to bleed the system?

many thanks

 

[seco services]

Give us a pic of the vent.

 

[ukal]

a couple of pics here showing setup, valve I cant open & pipe that has slight leak (pic with the plastic container. Its a minor drip, this pipe looks to be the bottom coil pipe from tank - could this be a problem?).

Hope these help?

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• ukal
• 1 May 2012
• 2

Untitled

• ukal
• 1 May 2012
• 1

Untitled

• ukal
• 1 May 2012
• 2

 

[ukal]

for anyone interested or has the same symptoms, this issue was a faulty valve which has now been replaced. Cheers