c/h boiler heating up but no hot water in system

[mikell]

hi all,yep it fire up ok and heats up but no hot water gets to the rads.
now I think thats the pump but I v read how to test the pump by removin the bleed screw,but if the pumps not runnning at all is there anything I can do to try to make sure that is indeed the real fault and not just a result of another fault ?
Also is it straightforward changing the pump,like for like ( if I have to of course!) .
sum up : it fires ,heats but nothing leaves the boiler.
thank guys for reading and please keep it simple for me!!!
ta!

 

[bengasman]

test for 230 volts on the pump

 

[mikell]

will do,but I think to do that ( correct me please if im wrong),I will have to loosen off the pump to spin it round as the housing the electrics go in to on the pump has its back to me ,so I loosen it off turn it half round there should be a little
screwplate id guess to access the wires? I only have a screwdriver tester but that would tell me anyway wouldnt it what I need to know ,power or no power ? if power then deffo pump gone?
thanks,will try it tommorow .

 

[gas4you]

You could try the other end of the pump flex for 240V if that is easier.

 

[Malc C]

mikell, does the pump body get hot even if it isn't running ?

Replacing a pump is quite simple. Should take you about an hour tops. I recently replaced mine and I was up and running in less than an hour.

1 ) - Turn off the power to the CH electrics and remove the cable from the junction box, noting what wire goes to what terminal
2 ) - Isolate the water supply to the system
3 ) - Carefully close the valves above and below the pump
4 ) - Once valves are closed, loosen off the large nuts securing the pump. You can use a pump spanner or B&Q do a water pump wrench for about £4
5 ) - when loose carefully remove the pump, along with the old seals.
6 ) - carefully clean the flanges of the valves and fit the new seals that should came with the pump
7 ) - Connect the cable to the pump using the old cable, or ideally a length of new cable.
8 ) - I wrapped a few turns of PTFE tape around the threads of the pump before re-fitting. Then refitted the pump, making sure not to over tighten the nuts
9 ) - Open up the valves
10 ) - Bleed the pump by loosening the centre screw until water dribbles out then tighten the centre screw back up.
11 ) Turn on the power and test

 

[mikell]

thanks for all the info malc, much appreciated.
The pump body does nt get hot at all ,not a murmer.
if I buy another pump are they all standard size threads ,universal fittings?
dont want to buy one nd find it doesnt fit the threads on my pipes!

Again guys thanks for all the help!

 

[swbjackson]

Wrapping ptfe tape round the threads of the pump as actually detrimental to getting a good seal. The seal is achieved between the two flat faces and the washer. The tape can make it more difficult to tighten. Also the new flex should be heat resisting ideally.

 

[mikell]

back to bengasman , I got the plate off and power is going in ( brown )lights up but nothing from the blue wires screw.
what is the white cylinder in the junction area ,to the right,about 1 1/2 inches long? a coil of some sort?

So what do you think then gents power going in but no sign of life,do I buy a new pump and go for it ?

 

[gas4you]

As you have shown you have 240V at the live terminal, it is time for a new pump

 

[mikell]

thanks, I just like to confirm everything with people who know much more than me ( seems thats eveyone and his dog then!) ,before I do it .
They are standard fittings though arnt they ?
and whats the difference between 15-50 and 15 - 60 ( I can see the differnce but dont know what 50/60 means oh and the 15 bit as well ) ta.

 

[bengasman]

50 is 0.5 bar and 60 is 0.6 bar maximum pressure; 50 is plenty unless you have a huge system

 

[mikell]

ahh -haa! I see,
thanks ,im now looking to buy one.
when I balls it up in a few days il be back!
really helpful you guys thanks to all