Replacing pump beside boiler

mail

My central hearting pump has finally packed up , how difficult would it be to change it, is there anything i need to do other than take old on off and fit new one. I imagine the system needs bleeding down, roughly how much would it cost to have a plumber do it.

robd

mail wrote: »

My central hearting pump has finally packed up , how difficult would it be to change it, is there anything i need to do other than take old on off and fit new one. I imagine the system needs bleeding down, roughly how much would it cost to have a plumber do it.

Relatively straight forward to replace yourself if you can use a wrench and wire a socket. Pump replacement is about €150 labour. Pumps cost €50-100 depending on brand/quality. Main thing is to make sure pump is same size so no pipework needed. You may not have to bleed/drain system. Most pumps are fitted with valves either side. These can be shut off with a screw driver. Valves look something like this http://www.pulsar.ie/plumbing-supplies/productdetail.asp?ProductCatId=521&ProductSubId=103&ProductCode=NRVP02

mail

Thanks for that , I am not a plumber but can do a few small jobs and have plenty of time on my hands at the moment ,plus i will learn a little. I wouldnt have known about the valves either side of the pump so have learned already, another plus for internet forums, thanks again

ntpm

mail wrote: »

Thanks for that , I am not a plumber but can do a few small jobs and have plenty of time on my hands at the moment ,plus i will learn a little. I wouldnt have known about the valves either side of the pump so have learned already, another plus for internet forums, thanks again

Definetly a straight forward plumbing job.... even electrician's would do it.:rolleyes:.

Just make sure you know where to isolate central heating water supply for heating, just incase.
( Easiest way is to tie up the ball cock/float in the small tank in your attic).

Isolate electrics to heating. Disconnect electric at pump motor.
Shut off pump valves, loosen Large valves on pumps (awkward part of job) , remove pump body,
use new gaskets ans sealing compound, refit new pump, retighten valves, open valves,
carefully open large flat screw on pump motor body to vent air in pump.
Reconnect electrics switch on pump switch on and
give yourself a pat on the back!!!

If they are screw driver type of valve on the pump then they make leak a little when turned on and off... not normally they reseal.

mail

I replaced the pump and didnt have much bother except couldnt open the valves either side so had to drain down the system and get new valves , but i now have a problem with air in the system and cant get it out , i have traced it i think to a hall rad ,when i open the vent no air or water comes out even when i took the screw fully out. I drained the rad and loosened the rad valves ,water coming out the valves as i thought they might be air locked, so am puzzled now as to get the air out. The rads upstairs are full of water and no air when the screw is opened. The thermostat cuts out as the water cant move around the system, the pump is placed in position the same as the old one with the arrow on the return. So after all that i may have to get a plumber as i thought it was just swap over the pump, any ideas anyone? by the way this is an old system with small expansion tank.

Sparkpea

try bleeding the pump at the screw on the front of it

maybe the boiler isn't full, loosen the flow connection at the top and see if you get any air out of it, u might need to get it run a little

the hall rad vent could be blocked, turn off both valves and take the air vent out and poke a needle or pin into the hole incase dirt is in it, you might hear a hiss but if u have the valves closed on both sides water wont flow out, so put the vent back in and open the valves again then try vent it.

DublinDilbert

+1 on air in the pump.

What orientation is the pump fitted in? These do get air locked, just loosen the big screw on the rear a few turns and when a drip of water comes out you should be grand.

aujopimur

The rad vent may be blocked, remove vent and clear it usuing a small nail or panel pin.
Now you know why plumbers quote what may seem like a lot for a 20 min. job.

stantheman8

Hi Mail.
Can you let us know how you got on?
I've been following this thread with interest as I have been trying to solve a similar problem.
Thanks!

mail

Hi firstly thanks for all the advice I have learned a lot from being on here, well I changed the pump ,couldnt get the old one off without replacing the valves either side so had to drain down the system and get new ones . I couldnt get the pump to pump the water around the system ,thought I had the pump the wrong way, turns out there was a major air lock in the pipes , so while I was at it I drained the system again and connected a hose pipe to the flow and another to the return and ran water through to flush out the pipes. I then filled the system again still no water moving around the pipes, so disconnected a radiator upstairs and one downstairs and connected a piece of hosepipe to the valve and let it run til air came out and hot water also. I fitted the rads again and they worked , I also flushed the rads out when I had them off ,some muck came out! Its working now but still getting some air in the rad upstairs , there is no airvent fitted on my system anywhere should I fit one upstairs the highest point? How is the air getting in when the pipes are full of water?I would appreciate some advice on this , thanks