How do I drain my Potterton Powermax HE115 tank??

[batman2]

Hi,
Still trying to fit an immersion heater to my Potterton Powermax HE115 Combi boiler.

Had a go at the weekend following instructions in the manual that say:

"Isolate mains water supply at stop valve on Inlet Control Group
and close / turn valve (handle at 90° to valve body) on double
check valve.
Fit a hosepipe to the tail of the drain valve (secure with “Jubilee”
clip), and run open end to a low level where water can be safely
drained.
Open nearest tap(s) fully (to allow air to enter cylinder) before
opening the drain valve above hose."

I cannot get to and therefore close the 'double check valve' as it has been fitted in a very tight space with the handle in the most inaccessible position. I isolated the water supply and connected a hose and opened the drain valve but pretty much nothing came out (after opening the nearest taps).

So, what does a double check valve do and how do I drain the tank if I can't close this valve? Or, am I doing something wrong?

Thanks,

Phil

 

[MarkBarl]

Assuming that your immersion goes into the top of the tank, you only need to reduce the water level by a few inches so that it doesn't come out when taking the heater out. You should just be able to turn your main incoming stop cock off, and then run the cold taps until nothing comes out, this drains the tank in the loft. Then run the hot taps for a few minutes to reduce the level of the water in the hot tank sufficiently.

P.S. Turn your boiler off whie doing this or it will try to heat the water in the tank.

 

[batman2]

Hi,
Thanks for the reply and it sounds like an idea as the immersion heater is in the middle of the tank.

The problem is that I don't quite understand what is going on with the taps. I switched the boiler off at the master switch and then turned the stop cock off. I opened the taps in the nearby bathroom and they ran for about 5 seconds and then stopped (i.e drained the water in the pipes but not the tank). Does the bolier control need to be switched on for some valve to be open for the taps to work? If not, why am I not getting any water out of the taps.

Your idea sounds fine if I can get the taps to work.

This is a combination boiler by the way.

Thanks,

Phil

 

[JohnD]

I don't understand this. If you have a combi boiler, why has it got an immersion heater? they normally go in hot water cylinders which are not usually installed with combis.

can you post a pic of the thing you're working on?

... run the hot taps for a few minutes to reduce the level of the water in the hot tank sufficiently.

if by "hot tank" we mean hot water cylinder, running the taps will not empty it at all, because the hot taps are fed from the top of the cylinder

 

[batman2]

Hi,

Sorry, that should read "Condensing Boilers with Integrated Hot Water Storage". It's a Potterton Powermax HE115 by the way.

Thanks.

 

[MarkBarl]

I don't understand this. If you have a combi boiler, why has it got an immersion heater? they normally go in hot water cylinders which are not usually installed with combis.

can you post a pic of the thing you're working on?

... run the hot taps for a few minutes to reduce the level of the water in the hot tank sufficiently.

if by "hot tank" we mean hot water cylinder, running the taps will not empty it at all, because the hot taps are fed from the top of the cylinder

It's academic now as it is not a gravity fed system. You are of course correct, however if you also left the cold taps open and assuming that they are physically below the level of the immersion and the inlet to the cylinder is not connected to the header outlet in some strange place above the level of the cylinder gravity should drain the level of the cylinder sufficient to replace the element.

 

[batman2]

Hi,
I'm still confused though. It's the hot water in the tank that I want to get rid of and so how will opening the cold taps drain that off?

 

[baxpoti]

Hi,
I'm still confused though. It's the hot water in the tank that I want to get rid of and so how will opening the cold taps drain that off?

Your doing OK except you need to open the HOT taps.

This allows air to flow back into the tank and hence allows the stored water to flow from the drain off. Can take 1-2 hours!

 

[batman2]

Hi,

I tried the above method last night (i.e shut off cold water supply, turn hot taps on in kitchen downstairs, open drain valve) and nothing happened. The hot taps ran for a minute or two before running dry and I had a small dribble of water out of the hose from the drain valve.

Any more ideas? The double check valve (that I can't close) is on the back of the fitting that has the drain valve on it. Is this the problem?

 

[baxpoti]

Photo would be helpful, It's possible the filling loop/drain is incorrectly fitted.

 

[batman2]

Hi,
Pictures being uploaded soon hopefully.

Had another look last night and the plastic knob that I can't turn is directly opposite the drain valve outlet on the double check valve housing. Presumably nothing will come out unless I can turn that or am I wrong?