Problems Bleeding a Powermax 140 Open Vented System

[leopardml2341]

Hello Folks,

Looking for some help - but first the background.

Rad failed in living room and emptied water all over the place - of course this happened whilst I was away.....

Have replaced rad and filled succesfully - i.e water from bleed valve. Bled all other rads, fine. Water in f/e tank and feed pipe not blocked as all rads full also water at CH pump bleed screw.

Water in pipe below pump but seemingly no water in flow pipe from heat store to pump. Checked by loosening compression joint.

Any ideas how to remove what seems to be an airlock at the highest point with no apparent bleed point ?

All of the other boiler functions are ok h/w is fine, ch pump operates and creates head as no water escapes from ch pump screw when running - only when static.

How do I get rid of the airlock - if indeed that's what it is.

Thanks in anticipation...........

 

[andytw]

This is odd because the domestic hot water is heated via a heat exchanger with hot water from the thermal store, so that must be OK.

The same water in the thermal store is sent to the radiators with the CH pump.

If the store is up to temperature and you call for heating then it really is down to the pump. Are you really sure it is spinning ?

Can you check you have mains at the pump when there is a call for central heating, do you have a multimeter ?

andytw

 

[leopardml2341]

andytw,

It had got me foxed too. - I knew there was apparently an airlock but couldn't find out where.

The reason why the hot water worked ok is that the level of water in the heatstore was above the take off and return for the (separately) pumped dhw circuit, but below the take off for the (separately) pumped c/h circuit.

The pipe from the f/e tank is 15mm - it also has an isol valve in it (naughty) - it will be removed.

When I loosened the boiler side compreesion joint, with the valve closed it issued forth air. Opening the valve allowed water flow into the pipe whilst still expelling air and a bit of water. eventually I could hear air bubbling through the heatstore tank and the vent pipe hitherto cold became hot.

Tightened isol valve compreesion joint, started c/h and hey presto circulation.

So airlock for certain - but where I don't know - poss in fill pipe, but why ?

What I didn't do (at 8 pm last night because I was a bit fed up by then) was check the vent pipe for a blockage, but even if there were one it must have cleared for hot water to rise from heatstore.

I will check tonight though and that isol vale in the pipe from the f/e tank is going at the next opportunity - There's an isol valve on the f/e filler pipe.

Rgds,

Andy