Help required please!

[Plumbo]

Hi folks, I have a plumbing conundrum in my new house and was after some advice and explanation of the defect.

Type
'Y' Plan system, Potterton FF40 boiler (2002), grundfos pump (2008) located in an upstairs bedroom cylinder cupboard. Original system was warm air heating, boiler new install 1992.

History
I moved into the house a few months ago, surveying the loft I noticed that the Cold feed and expansion cistern for the central heating was boiling hot. I asked the owner to get this fixed before I bought the place.

He came back with a plausible fix of a blocked cold feed pipe (friends experience), and had 'fixed' the problem. Checking the fix, I noticed that the guy (BG apparently) he got out to work the problem had ran the cold feed into the open vent pipe. A heating engineer I phoned said it was not correct but would be safe enough; the cistern was no longer getting hot and overflowing.

Once in the house I had somebody around to change the cold feed pipe and revert the system back to normal configuration. Once connected the F+E cistern got boiling hot again with the O/V and CF pipes hot aswel, defo no blockage!!

Problems
Due to current config of C/F running into O/V Air in the system is driving me nuts, I gather because it has no vent or way of escaping.

Observations
-The air glooping is only when the three way valve is porting to the DHW cylinder not the C/H. It only happens when the cylinder is almost at its pre-set stat temperature 65.c
-The boiler is set to 1 but still kettles (with silencer added)
-The pump speed is also set to 1
-The open vent is approx 5' from highest pipework to the top of the CF+E.
-Cold feed Pipe pipe run is approx 3' more plus 3" of water in the tank.
-Pipe run =Boiler Flow side, O/V-C/F distance 1 m, C/F- Pump (suction side) 30cm. Pumping downwards.

Questions (shot in the dark)

How can I get the air to escape?

Is lack of header pressure causing the water to boil early, hence glooping, kettling?

Is the pipework config wrong i.e O/V is too far away from C/F, neutral zone etc? How can this be resolved in a little cupboard. ref J Mac pumps


A link to a set of Flickr photo graphs of my cupboard is (if) available.

Sorry for the long winded thread. Any help would be gratefully received.

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[TheGasEngineer]

You are asking to be taught how heating systems work in one easy lesson and I guess no one will take on that task. You need a plumber. There are standard ways of designing a heating system and one is to connect the feed via an anti-gravity loop. Think for a moment what happens to hot water in a vertical pipe... it rises. So make the feed go downwards for 6" and then turn it upwards and take it to the F&E cistern. That will stop the hot water rising and heating it. The feed and vent should connect within 150mm of each other and down stream of the pump. I prefer to fit an air separator with a constant rise in all pipes to make the air-sep the highest point. Then the system self-vents and makes filling the system much easier. I think though you need a plumber. In fact if he tells you all this without prompting he's probably OK. If he umm and ahhs then move on to the next guy.

 

[Plumbo]

Hi GE,

Thank you for your time in replying to my thread,

The you need a plumber response is fair enough and could be the response for all the threads posted and no need for the website.

I'm sorry if my post's content reflected that i am doughnut but I can assure you my knowledge of thermo dynamics and hydronics is fairly sound in my own occupation. I have fitted a few systems in the past from scratch reading a diagram but have never had the pleasure of rectifying somebody elses balls up. Hence the call for help and somebody with more experience to bounce ideas off. That is what we do on my professions forum.

I have found what I am looking for on the website provided by the technical discussions the site offers i thank these guys and girls that obviously couldn't respond to my own problem.

Sometimes you don't see the wood for the trees, as in my case.

Cheers all.

Cheers all.

 

[BLOD]

Hi,
just read your post - what was the problem in the end ?

Glad you've sorted it !

Blod

 

[Bernie2]

Hmm!

Fitting the cold feed into the vent was quite common at one time. But I always found in practise getting the air out of the system was just virtually impossible at times.
A good pointer is to go on the J.Macs pump tool site and it shows you some configurations. Its good, and explains a lot of things. Its easy to understand as well.