A tad foncused!

[rolyatescort]

I have a Potterton combi feeding 4 downstairs rads and 4 upstairs rads. About 2 months ago i replaced 4 of the old rads(2 up, 2 down) and bled and balanced the system at the time. Everything was hunky dory until 2 days ago when the furthest away downstairs rad wouldn't come on at all and the upstairs only got warmish, i was also getting increasing pressure at the boiler(just below the 3 bar mark from its usual 1.5). I found that the kitchen rad(2nd in line downstairs) was cold at the bottom. I turned it off and everything else started working again, but still with the pressure rise. I have removed it today taken it outside and flushed it out, once refitted it works fine, but the earlier symptoms for the other rads have returned.

Any ideas?

Thanks in advance...

 

[brumylad]

try bleeding the pump.

Are you sure the pressure did not always rise when the system got hot and you have only just noticed it. Does the pressure reduce when the system cools again

 

[rolyatescort]

Thanks for that reply. I am definite that the pressure has never risen before, i got into the habit of checking it as one of the old rads had a leak so it was constantly dropping and i have continued to monitor since replacement. Yes, the pressure does reduce when the system cools but not always to the same place, anywhere between 1 and 2 bar.

How do i bleed the pump and where is it located?

Thanks in advance.

 

[CH4]

Was the filling loop disconnected after refilling? If not, then its valve may be letting by and causing the pressure rise.

To bleed the pump, let the system cool (to avoid scalds), protect electrical parts from splashes, loosen the large diameter flat screw in the middle of the pump's motor housing and allow water to escape (into a suitable container) until the flow is free of air bubbles. NB if the water gushes out then the pump's bearings may be worn.

 

[brumylad]

the pump is usually inside the boiler. consult the handbook.

 

[rolyatescort]

Thanks for those replies Guys, i will give that a try later on.

P.s. No, the filling loop si never disconnected.

 

[rolyatescort]

By Large flat screw do you mean the large black bolt head in the centre of the pump? The only large screw i can find is the drain screw underneath the pump. If i undo the drain screw i get some dripping and some air but if i loosen it far enough to get the air out the water starts to spray everywhere and the whole room gets drenched including me! Please help...

 

[ChrisR]

YES . If you'd said you had a Puma he would have said "black bolt thing".

Your expansion vessel (= pressure vessel) may well need pumping up - do a search to find how. Also you may find now that the pressure releif pipe drips - check it.

 

[kevplumb]

put the screw back

 

[rolyatescort]

Thanks for that i will search for expansion vessel. How should the boiler be set while i'm bleeding it? The system is cool, heating and hot water off, then i have isolated the power. I have loosened the black bolt (it was only hand tight is that correct?) to the point that it is almost out and there is nothing, no escaping air or water. What is the problem do you think? or will my search for expansion vessel answer that to?

 

[kevplumb]

I have loosened the black bolt (it was only hand tight is that correct

yes
you dont bleed the ev

drop the pressure and check the ev
should be 1 bar /no water out of the valve
pump it up to app 1 bar

have a look at
//www.diynot.com/forums/viewtopic.php?t=18832
might help

 

[rolyatescort]

I have loosened the black bolt (it was only hand tight is that correct

yes
you dont bleed the ev

drop the pressure and check the ev
should be 1 bar /no water out of the valve
pump it up to app 1 bar

have a look at
//www.diynot.com/forums/viewtopic.php?t=18832
might help

Thanks for that Kevplumb. I wasn't wanting to bleed the EV, i was trying to bleed the pump but there was nothing there. (i realise that my post was misleading, will proof read in future).

I have read up on the EV and pressurising it. Do i need a pressure guage on the schraeder valve or does the pressure on the system guage change? Is a foot pump sufficient enough for the job?

Thanks in advance,

Tony.

 

[IanDB]

You need to open a valve on the system to ensure that once you start pressurising the EV the water you push out of the chamber has somewhere to go. Otherwise you'll just pressurise the system again and not put much air in.

As the pressure gauge on the boiler measures water pressure it should stay at zero. You need a separate guage to go on the schraeder valve. You can use a footpump with a guage (if you can get it in) but a bicycle pump is easier to manage - you just have to check the pressure with a guage now and then. Once you've charged the EV to 1 bar (15psi) you can then re-pressurise the water system to 1 bar.

 

[rolyatescort]

Thanks for that Ian. This morning i drained the system using the drain under the boiler. Pressure dropped to 0. I then checked the pressure at the schraeder valve and that was 0 also. I pumped it up to 15lbs. Whilst doing this i left the drain open. After doing so i checked the system pressure it was still at 0. I then filled the system up to 1.5 on the guage. When i started the system up again it definitely got hotter quicker but the boiler is making a lot of glugging noises. I bled all the rads, no air was present. I want to bleed the pump, i have followed the directions in other posts, but i can loosen the black hexagonal bolt as far as it will go and no air escapes and no water escapes. What am i doing wrong?

Thanks in advance, Tony.

 

[kevplumb]

let the air out of the ev and see if you get water out of the valve if so ex vessel is dead