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iansas · Joined: 27 Dec 2003 Posts: 40 Location: brook surrey uk

thanks thescruff for your info and the drawing. it is just as alan suggessted.
i have taken off the check valve on the vent so thats ok but i woundered how it would cause the water to not return into the system as i thought it would come back through the expansion / cold fill pipe once cool.
as for the layout i will have to get stuck in and change it. i was going to ask you john what does the bypass actually do and how important is it.

thankyou all that has replyed to my concerns i have found it really valuable, quick and interesting.
cheers
iansas

thescruff · Moderator Joined: 03 May 2003 Posts: 4680 Location: Bath

The expansion pipe is just that, water goes up and comes back down it has to be an "open vent" no valves, of any sort.

The by-pass is not always required and some boilers have them integral, the Camray I dont think has one so you may need an external one fitted.

It does two main jobs, it allows water to circulate through the pump when the thermostatic valves are closing, and it reduces system noise, by relieving the presure as they close.

scruff

iansas · Joined: 27 Dec 2003 Posts: 40 Location: brook surrey uk

thanks for the drawing john.
just one quick question Very Happy

the expansion pipe, should it be in a straight lenght of pipe or can it be at a 90 degree ?
also can the cold feed be in 22mm or is 15mm better?
the auto bye pass valve is this electricily operated or sprung ( not electric !)
alright i know that was 3 questions but hey you are very helpfull
cheers

thescruff · Moderator Joined: 03 May 2003 Posts: 4680 Location: Bath

Expansion pipes must rise continously but not necessarily in a straight line.

Cold feed can be 22mm.

By-pass is mechanical I prefer the 22mm Danfos AVDO.

scruff

iansas · Joined: 27 Dec 2003 Posts: 40 Location: brook surrey uk

sorry john i didn't explain my first question very well.
where the expansion leaves the boiler flow can that junction be in a horizontal section (as per your drawing) or will it still be effective if it was coming off a 90 degree turn into the short section before the pump? does that make sense? and do you need to put an airator at that point or just a simple T ?
Very Happy

cheers

thescruff · Moderator Joined: 03 May 2003 Posts: 4680 Location: Bath

You can tee off anywhere on the flow provided the cold feed is within 150mm, and it's before the pump.

The ideal is the expansion pipe takes the air off the system if you connect it to a high point, and also vents the pump.

forget the air seperators their rubbish.

By keeping the two pipes as close as possible it balances the cold feed and expansion.

scruff

iansas · Joined: 27 Dec 2003 Posts: 40 Location: brook surrey uk

finally changed the layout Very Happy

i did a quick fill at 10pm at night to try and get hot water for kids and her royal highness!! i fired it up and i got some banging straight off but thought i could bleed it properly in the morning, however there was none of the usual early morning bang as i can only assume it vented it self during the night Very Happy

i went round the house to vent the rads and there was a little air but not much.
the whole system seams to work much better. not a single bang. i even changed the pump whilst it was drained as this must be 10 years old and thought it would save me doing it in a couple of years.
it all appears to be really happy , could the rads be hotter i ask myself Question

anyway i would just like to thank those involved in helping me especially this site, it has saved me a fortune in time and money. i have told everyone i know about it.
thanks
a happy boy Laughing

thescruff · Moderator Joined: 03 May 2003 Posts: 4680 Location: Bath

Glad your sorted, looking at the forecast you will need it working.

j0hn Cool

iansas · Joined: 27 Dec 2003 Posts: 40 Location: brook surrey uk

just when i thought it was sorted it has started banging again Sad

the noise is just like my kettle boiling but quite loud.
i have also noticed that when the pump kicks in there is a noise from the rads just like a cross between a clap and a crunch of a couple of crisps (potatoe chips for our far west friends). i know this is an odd discription but couldn't think of anything else. Confused

i filled the system up with fernox ( one gallon ) and this i chucked in at the begining saving some for the header tank. there was lots of bubbling noises as the air escaped, the rads had some air in but not much. i tried to balance the system, by turning the return, rad valve, on each rad (starting down stairs and furthest from pump), i acheived a 10 degree ish difference (hand hot difference) and thought all was well. the pump i left at the no 2 setting as this worked well enough ( i thought ), also recomended by the helpful john the scruff. all was great untill my wife kindly noticed the crispy sound Laughing

at pump start and gradually the banging has returned.
i have noticed the 3 port valve is put in vertically and not horizontally as the paper work recommends. does this make a difference.
so to the question; why for thout boiler banging again

is it the boiler. could it be the layout of pipe. is it enought fernox . have i put the new vent and feed in correctly. has the system got some other fault Question

well that should get you thinking,
ofcourse i enjoy plumbing but this is starting to Twisted Evil

thescruff · Moderator Joined: 03 May 2003 Posts: 4680 Location: Bath

Perhaps you better update the drawing and post it or digi-pic.

Include the pump and valve.

scruff

AlanE · Posted: Tue Feb 03, 2004 7:58 pm Post subject:

Banging boilers are normally suffering from poor circulation causing the water in boiler to boil.

It is a case of systamatically going around the system to check all components. Might be worth sending a sample of heating system to fernox for them to analise. System might be partially blocked causing poor circulation.

Alan

iansas · Joined: 27 Dec 2003 Posts: 40 Location: brook surrey uk

hello john
ive just mailed the layout and pics to you.
i drained it down and flushed out 4 times today, lots of bits came out into bowl.
i just thought some discription of the lay out might help.
the pump has a 90degree bend right next to it and the 3 port is right after that. i didn't put a auto bypass as the plumbers didn't have one and the tech for my boiler said i wouldn't need it unless i have thermo rad valves. also pipe to boiler is 28mm but last meter is 22mm. also the air vent sends a splash of water out when the pump stops ( odd Question

)
i'm not sure whats going any more perhaps i should move house Exclamation

thanks again for the time you put in.
alan can the water sample tell all if fernox test it Question

AlanE · Posted: Thu Feb 05, 2004 8:37 pm Post subject:

A water sample test should show if the water contained any substances that would cause a blockage.

You could add some sentinal sludge remover to the system water and run it for a week.

Then make up an adapter to fit the pump valves so that you can feed mains pressure water in through one valve and a drain hose out the other.

Then force water through the system to flush it with one rad turned on at a time. Swap the two hoses over and repeat with water flowing other way.

Alan

iansas · Joined: 27 Dec 2003 Posts: 40 Location: brook surrey uk

thanks alan.
i will try flushing out system as you suggested.
is it normal for the vent pipe to spurt out water just as the pump stops Question

john i haven't any thermo rad valves. and the 3 port valve is a danfoss HSV3 it has a 90 degree into the valve and the hot water also has a 90 degree out, could that slow things down. also i know you said to put a by pass valve in and i didn't would that help the flow Question

thanks again
iansas

thescruff · Moderator Joined: 03 May 2003 Posts: 4680 Location: Bath

I'm sure I said if it works on 2 then ok if not then 3 is normal.

On the 3 port valve which port is the heating.

By-pass wont improve the flow rate.

Little spurt is common but not normal, something is amiss and trying to put my finger on it.

Have you tried running the boiler with the towel rail valves turned off??

scruff