Calorifier advice pleeaase............

[LeonF]

This re-commission seems to be going on for ever !! Tracked down the water in the lockers to a leaking water tank duly replaced today. Ran the engine for an hour.. no hot water.. ran it some more...still none ..
Checked coolant....hot, but tank not pressurised.. was easy to open the filler cap. Water was running freely from heads and sink tap, just not hot at all. I never drained down the tank over winter... discovered there is a lever to do it today!! When I depressed it water spurted out, so guess there is no air lock ??? Suggestion have been that there is an air lock, the water pump is not working properly, or the thermostat has failed, not allowing the coolant to circulate. I have not drained and refilled the coolant , this was next on the list to be done. It is a small rectangular Nautic.

 

[Danny]

You should be able to check if there's water flowing through the calorifier heating coil by feeling the pipework. Once the engine thermostat opens you should feel the input pipe to the calorifier get hot - then the return pipe should start to get warm a bit later. If the calorifier is above the level of the header tank you may get an air lock in the heating coil although normally the coolant flow should be enough to sweep any air back into the header tank. You can also get an airlock when the calorifier is below the level of the header tank, if the pipes loop down below the level of the calorifier (which they should do to prevent conduction cooling of the calorifier).

 

[Oldhand]

Heating tube in calorifier crushed by expanding ice in undrained tank over the winter? I doubt if this can happen, just a thought...

 

[LeonF]

Thanks Danny...hope this is the problem as the calorifier is above the coolant tank. How do I clear the air lock if there is one ??? Hope it isn't crushed by ice as Old Hand suggests............

 

[wragges]

Check out this thread. I had the same problem and it was nothing near as 'techincal' as a failed thermostat or air lock, just good old fashioned crap (read clay) in the pipework.

http://www.ybw.com/forums/showflat.php?C...rue#Post1009282

 

[Danny]

If you think it is due to an airlock in the heating coil then first top up the header tank almost to the top and then start the engine. Wait until warmed up then run for a while at high revs to hopefully sweep the air out of the coil.

If that doesn't work then you've a bit of a problem! If you have the traditional type of pressure cap on your header tank with a bit of tube sticking out the side of the filler then maybe this would work:

<ul type="square"> [*]Attach a hose to the tube [*]Loosen the top hose at the calorifier [*]Replace the pressure cap with a blanking cap [*]Fit a funnel to the hose and hold above the level of the calorifier [*]Fill the funnel until coolant comes out of the loosened calorifier hose (or you could maybe blow down the hose!) [*]Refit the calorifier hose and remove the other stuff [/list]

Warning! I've no evidence this will work - it's just what I'd try if I had that situation! In my experience a few revs has always flushed the air out OK.

Best of luck!

 

[LeonF]

Thanks guys...I am away for a week in, hopefully some sun. so will give it all a go on my return. Will let you know the outcome..

 

[vyv_cox]

I can't add much to what Danny says. I have spent considerable time trying to eliminate airlocks, so be absolutely certain that the system is full before assuming you have eliminated them. One thing to be aware of is that having the hoses connected the wrong way round will completely stop the flow of water around the system. The hot water leaving the engine must go to the upper end of the coil at the calorifier.