Pump blocked or needs replacing?

[dibely]

Hi guys,

Our central heating has stopped working recently and after a little investigation I believe this to be an issue with the pump but I am not sure if it is just blocked in some way and can be corrected in situ, or whether it needs replacing.

The pump is Wilo Gold about ten-fifteen years old.

The first time I noticed a problem the CH was on but none of the radiators were heating up. I checked that the boiler was lighting and that seems OK (we get hot water) and the motorised valve shifts position when switching between HW and CH so my attention focused on the pump which wasn't running at all.

The pump has a variable speed and was set to position 2 originally and changing it to position 3 appeared to fix the problem but the next day it would come on briefly every so often and then stop. There was quite a bit of gurgling so on the assumption there was air in the system I opened up the bleed screw and sure enough air came out before it started dripping but this didn't resolve the problem.

I also tried using a screwdriver to turn the rotor via the bleed hole to see if it's just a bit stuck. It was quite difficult to turn the rotor the first few times I tried this - I wasn't sure if it should be difficult or not as it later became a lot looser? Again this seemed to ease the problem after a few stop starts and a few taps with the screwdriver(!) but this morning it won't start up again.

In case it's important, so far when I have got it running for any lengthy period it's only been with the speed position set at 3. It doesn't even seem to try at 2 or 1.

Does this sound like it is just blocked or that the pump is actually failing and now needs replacement? Is there anything else I can try that might get it working?

Thanks in advance for any help,

Duane

 

[kevplumb]

replace it

sounds on its last legs fella

 

[dibely]

Thanks for the reply kevplumb, It's looking more likely I will replace the pump now.

If I replace the pump is there anything I need to look for in particular with a new pump or are they fairly standard with regards to size, connection, etc?

Also I have had a go at closing and opening the valves either side of the pump with a screwdriver in preparation for replacing the pump - I believe they are ball valves. Am I right in thinking these should only turn a quarter turn to either side to open/close the valve?

The valves are particularly difficult to turn so I am starting to think that these may need replacing too unfortunately so if I need to replace the valves as well do I have to drain the system or is it possible to replace these without draining the system?

Kind regards,

Duane

 

[kevplumb]

If I replace the pump is there anything I need to look for in particular with a new pump or are they fairly standard with regards to size, connection, etc?

more of less standard

I believe they are ball valves. Am I right in thinking these should only turn a quarter turn to either side to open/close the valve?

yes

The valves are particularly difficult to turn so I am starting to think that these may need replacing too

not unusual bit of wd 40 might help

so if I need to replace the valves as well do I have to drain the system or is it possible to replace these without draining the system?

depends on your system

you could bung the header tank if you have one of try freezing the pipes View media item 17225

 

[nickso]

the new pump will be that same fit.

if the valves haven't been touched in 15 years chances are the will be sized or will leak if you do get them moving, ballvalves are pretty **** really.

you can either drain the system or bung the feed tank in the loft (assuming you have an open system).

 

[dibely]

I'll give a bit of WD40 a try to see if that helps first.

FYI I believe our CH system is an open vented one with a tank in the loft, cylinder motorised valve, and pump in an airing cupboard and the thermostat, programmer and boiler downstairs.

Using some kind of pipe freeze sounds like a good idea if this is possible as being a novice I am a bit apprehensive about draining the entire system so would prefer to only resort to this as a last resort.

Many thanks,

Duane

 

[Garfeild]

Pipe freezing could be iffy if its the first time youve done it.
You dont really have to drain the entire system,just to below the pump.
Either drain expansion tank out via drain off downstairs,or (what i normally do) bung the outlet from the tank,blu tack works fine,form it into a carrot shape,drain out downstairs but dont open air vents on rads,then youve only drained the bit of pipe from tank to pump.

 

[dibely]

Ah OK a partial drain doesn't sound as bad.

If I have to resort to any draining at all, when I come to refill the system would I need to add any chemicals or anything? I understand that the system should contain an 'inhibitor' so when drained, either in part or full, would this need replenishing?

Regards,

Duane

 

[dibely]

Hi guys,

I've managed to replace the old pump with a new one that works but now have an issue with our boiler cutting out after a few mins and not starting up again.

I had to replace the valves which involved a partial drain as suggested so could this be some form of air lock in the system? If so how do I find and remove it? Or could this be something else?

Thanks,

Duane

 

[Hugh Jaleak]

Its an obvious question but not unknown.... The new valves are open ?

 

[dibely]

Yeah, the valves are open.