central heating pump....HELP.

[JAMIE2010]

OK guys some help or advice would be great. Drained the central heating system down today to change some radiator fittings with leaky olives. Filled it all after completing the work,and the central heating pump,literally ground to a halt, there doesn't seem to be trapped air anywhere. I've fired up the central heating again a few times to see if the pump will kick in but again no joy. It seems to make a crunching,grinding noise....sorry if that's a little vague....but I'm no plumber,hence asking for your advice.
Thanks Jamie.

 

[Simon F]

remove the bleed screw from the pump ( with heating off ) see if you can tun the spindle, could just be stuck up

 

[tipintim]

Give it a sharpe knock with a hammer

 

[diamondgas]

:iagree: see if the pump spins freely manualy! That's if you can access the impellar shaft

 

[JAMIE2010]

Hi thanks Simon,tried that earlier its a grunfoss 15-50 pump. Just now noticed that the isolation valves on either side of the pump are leaking too. So they will need changing I may as well have the pump off tomorrow change the fittings and take a close look at the pump while I'm at it. May be able to give it an overhaul at work...failing that buy a new one. I wonder is the changing of these fittings a bigger job than a notice like myself can handle?

 

[diamondgas]

Must be the ball type with the slotted screw head! Another drain down by sounds of it ... Most likely a new pump would be on the cards rather than mess about in this cold spell

 

[Ruski]

Sounds like my scenario last week - for which I have Diamond and others to that again for oll their help!

http://www.ukplumbersforums.co.uk/central-heating-forum/30601-i-know-its-bad-but-what.html

The finished result Jamie - if you can drain it all down and have a couple of adjustables it's easy - spend a tenner on new valves too - even for a novice like me!! (Just make sure you have pump pliers/adjustables big enough before you start...)



HTH

Russ

 

[JAMIE2010]

Would any of you guys be able to tell me how much of a big or small job this is. As the fitting on the end of the two pipes in and out of the pump have leaking isolation valves.....easy to change?

 

[diamondgas]

Jamie they are as easy as you are compitent More compitence the greater the ease IMO.

The big job is getting it all to work again afterwards. The introduction of air to a drained system brings with it inherent problems you learn to overcome with experience!

 

[Nat]

If access is good its a pretty straightforward job. Drain down heating. Isolate electrical supply. Remove pump. Remove wiring. Undo compression nuts and remove pump valves (I would just leave old olives and nuts on) and then replace and rewire.

 

[JAMIE2010]

Thanks for all your help guys......and as for my compitence,I guess we shall see in the morning.....I repair turbines for a living so small pump must be a breeze.....(all bravado)
Must Add what a brilliant and helpful forum this is. I had replies wgtgmg minutes of posting.

 

[Nat]

Jamie they are as easy as you are compitent More compitence the greater the ease IMO.

The big job is getting it all to work again afterwards. The introduction of air to a drained system brings with it inherent problems you learn to overcome with experience!

This is true. I have spent hours trying to get around airlocks. Hopefully you won't have this problem.

 

[PlumbBobBob]

one thing i would add is to lock the three port or two ports open (whichever you have) when refilling the system as this cuts down on airlocks.

 

[SimonG]

Use gate type pump valves and don't forget the inhibitor

 

[Ruski]

I replied in post #7 - but it got delayed!! Picture of my replacement - amateur attempt so you're not on your own!!

Best of luck

Russ

 

[JAMIE2010]

hello again guys.
So after all the great advice at the weekend,I bought and fitted my new pump.....works a treat and
all the radiators upstairs are piping hot.......but alas radiators downstairs are as cold as ever. I've tried bleeding them,and I'm getting water out straight away,but the pipes that feed rads are also cold.
I'm nearly there chaps.....a little more advice would be superb.
Thanks Jamie

 

[MattWeth]

Are the zone valves (assuming you have them) operating correctly?

 

[JAMIE2010]

hmmmm now you'll have to explain what a zone value would be,and I'll tell you if I have them.

 

[MattWeth]

hmmmm now you'll have to explain what a zone value would be,and I'll tell you if I have them.

Motorised valve - you could have two 2 port valves or one 3 port valve, but as you have half your heating working (and I assume hot water) then probably 2 port.

They'll look something like this

and they'll be somewhere near your cylinder / pump.

 

[diamondgas]

You may have an airlock or twi Jamie. Try turning the thermostat on the cylinder to it's minimum or putting your programmer on to central heating only, if you can. That should allow the pump to work for just the radiators. If still no heat then turn off the ones working so that the pump can push to the one's that aren't! Once you have heat to all the ones not working then turn all your radiators back on again I'm assuming that it's air locks, by-the-way

 

[MattWeth]

Good point by diamondgas - I forgot that you'd drained down and replaced the pump valves too :banghead: