Domestic hot water not very hot

[kevplumb]

might be an idea to tell the op how to do it

 

[tamz]

I'm sure he'll be a quick learner

 

[cmother1]

You've probably gathered that loosening the top of the coil isn't exactly a popular solution. I'm not exactly sold on it myself, but it definitely will get rid of an air lock. The problem with it is that you might not be able to get it watertight again when you tighten it up. I'd rate your chances at better than even. But just think, if it didn't seal you'd have to drain down to fix it and then you could take the opportunity fit a bleed valve at the top of the coil. Problem solved for good.
Do you feel lucky?.... well do you?...... Seeing as this is the most powerful Stillson wrench in the world........ (What am I on about?!)

 

[deldol]

Only thing I'm not sure about is whether I need to remove the thermostat. About the only thing I've needed to do with my Glow Worm in 25 years is to replace the thermostat twice.

 

[kevplumb]

yes remove the sensing head from the pocket
and stay close to the boiler stat to turn it off

in case your bottle goes

 

[tamz]

I had just typed out a step by step guide to do this but have decided not to post it.
deldol if you want to know how this is done send me a PM.
Look in my profile.

 

[deldol]

Thanks again, especially to tamz, kevplumb and gassafeman, for your advice. It worked a treat and we had lots of nice hot water.........for four days and then the primary stopped circulating again. Repeated the treatment, got the hot water back..........and it lasted another four days. Did it again yesterday and now crossing fingers that it will last - but I'm a bit suspicious of an endemic problem if air is getting back into the coil after the water's been flowing smoothly for several days. Any idea how the air can be getting back?

 

[Agile]

I did have a problem with an air lock in the coil last year after I had drained the CH system, but that did eventually clear and up to now I have not had further problems. I do not think the current problem is an air lock and may well be a furred up coil,

Thanks in advance for any advice.

Its too late for you but it may help other people!

If you have an airlock the LAST think you should even do is to drain the system!

That fills the entire system with air and maks it worse!

A cool return implies a lack of flow,

That can be a lack of pumping, a blocked heating coil or an airlock.

Air locks are common on gravity systems but hardly ever seen on a pumped system.

With a properly designed system with methods of removing air then an airlock will never occur.

Blockages are usually within the cylinder fitting or the first 60 mm of the heating coil. Opening that fitting ( from the compression nut ! ) will usually show everything. Nupty installers often dont leave enough pipe movement to permit this maintenance action.

Tony

 

[deldol]

The air lock last year was not before but after I had drained the system, which I needed to do to change a leaking radiator valve. In any case, the system worked fine for over 6 months after the air lock cleared itself.[/b]

 

[deldol]

Guess what? Hot water worked fine after my last fix - but only 3 days this time (see my post on Tuesday 22nd at 9.59am).

Has anyone any ideas on how air is getting back into the coil after the primary has been circulating fine for 3/4 days?

 

[gassafeman]

I boil the H/W by removing the boiler stat. Clears all air locks ive ever had.

Belt & braces for that approach though!

Last time I did was 3 months ago when a fellow plumber had tried 'everyting' in his book to get gravity HW to work. Had it fixed in 20 minutes and he took all the glory then telling me how the customer had better hot water now, than in the 10 years she lived in the house.

Paul