Lukewarm water from an Aga

[Steth]

Our hot water cylinders (2) are heated by an Aga which is alight and up to full temperature according to the gauge on the front.

Today the water from all hot taps is only lukewarm. The upper pipe from the Aga with the bleed valve is lukewarm, the lower pipe with the drain cock, is cool.

The feed and expansion tank in the loft has water in it and the ball cock works if depressed.

I feel the loop from the Aga to the HW cylinders must have air in it. Is this possible? If so, how do I get rid of it?

I have last week installed a power shower which I would have expected to possibly introduce air into the main HW pipework, but can't see how it can have got air into the Aga loop.

The bleed valve on the upper pipe from the Aga is turnable by hand. I'm tempted to turn it further to see if air comes out but have visions of water squirting out whilst I'm left holding a piece of brass in my hand!

What should I do?

 

[oilman]

Try posting here

 

[chrishutt]

Open the bleeding valve! Don't take the cap right off, just loosen enough to let air escape. Let us know what happens

 

[Steth]

Opened the bleeding valve. As expected left with a lump of brass and a spring in my hand, but happily no water (nor air escaping noise)

I't's a bit ifficult to tell what's changed as I'd put the immersion on to get hot water and I'm assuming that the reason the Aga pipes are now hot is that the hot water in the cylinders is heating them backwards as it were.

I'll turn the immersion off and see what has changed after tomorrows showers etc.

Thanks for the advice so far.

 

[chrishutt]

Sounds like you've undone a safety valve! It seems that the jumper has stuck shut, very luckily for you! Better put the cap and spring back on - a bit gingerly though.

 

[Agile]

Not much of a safety valve if its seized up!

Better to cool the system and put on your oilskins and free it up!

 

[Steth]

Turned off stopcock to header tank, drained Aga loop (isn't it easy to roll up a hose when it's had hot water running through?) Took the cap and spring off the valve wiggled the bottom bit to free it off, replaced spring and cap, screwed it half down as that's where it was to start with, put some inhibitor in the tank, turned stopcock back on.

Both Aga pipes are now warming up. I await hot water.

 

[Nige F]

wromg post

 

[HarrogateGas]

BE WARNED!! do not attempt to drain off any part of the aga system untill the Aga has has 24hous to cool. You could be left with a bill in the region of £2500 to replace the heat exchanger seals.


You have been warned!

 

[Steth]

One day later and the water is definitely hotter for having drained and refilled the system (or in spite of it).

Water at the tap is 45 degrees as measured by a jam thermometer but still hot enough to kep you hand under. I'm sure it was previously too hot to do this.

I assume that there is no way an air lock can form in the system as it should simply vent through the loop that hangs over the header tank?