Pump removal problem

[johnscales]

Hello all.
Woke up this morning to much loud banging coming from the boiler.
Following an hour of stopping starting and a process of elimination I realised that the pump was not working. Confirmed after another hour or two of flushing out the system and retrying (thirty odd squid of 2 month old scale remover and water conditioner literally down the drain. grrr)
Anyhow I did the screwdriver to the ear trick and heard nothing from the pump on startup, just an electrical buzzing. Also noted that the pipe above the pump was now roasting and the pipe below was considerably colder.

Onto the problem then. I've drained the system and am in the process of removing the old pump. Needed some wd40 to free the isolaton valve union nuts up which has worked a treat. However, the isolation valve union nut seems to only spin on the side of the isolation valve (top side of nut). On the underside of the nut (the side that connects to the pump thread) I can see the thread but the nut won't undo here. The result being that the pump freely moves back and forth but won't actually undo as it can only spin about 200 degrees before coming into contact with the wall. It's a little difficult to explain in words so if i'm not making much sense let me know but i suppose what i'm getting at is shouldn't the nut be free to spin on it's own without the pump or the iso valve moving?

cheers frustrated and soon to be cold when the calor gas runs out

 

[misterdubya]

Make a small notch in the troublesome nut with a junior hack saw.

Place a large flat-headed screwdriver into the notch on tap the other end with a hammer - obviously in an anti-clockwise direction. This will get it going. Or just saw right through it.

Failing that, why not oik the pump out with the valves attached, seeing as you have drained the system - and replace the valves aswell.

EDIT: What tool are you trying to undo the nut with? Never ever use grips.

Mr. W.

 

[seco services]

bit confusing.
but yes the nut should spin on its own.

 

[johnscales]

No joy as yet but have just been having a go at the misterdubya method (didn't try the hack saw bit) so am pleased that I have the right idea and that i'm correct in thinking that the nut should be independent of both the valve and pump. Seems almost fused to the pump.
I didn't hammer away too much before checking back here but will go and have another go. Failing that i'll go for the valve removal method.
Will post back with the result.

Thanks

 

[johnscales]

also, should heating the nut help? and what size nut will I need to buy should I need to cut right through? The pump is a myson compact cp53 and yes, i've read nothing but posts saying how crap they are. Mine's lasted 10 years without complaint though and was fitted by council before I brought miy property. My replacement is a grundfos.

 

[misterdubya]

The old pump may have been installed with fibre washers which swell as they get wet. This can make them nuts incredibly difficult to undo - but I've never failed with the hammer and screwdriver yet.

But I only ever do that if I'm using the valves and have not drained the system. Its easier to just pull the lot out if your not relying on the valves to work.

Renew the pump with rubber washers.

Just read your post - if you saw right through it, just buy a new pump valve (22 or 28mm). The nut will come with it as you cannot buy the nuts seperately IIRC. Oh, and your new pump will have come with rubber washers.

Mr. W.

 

[Agile]

Did you ever try to spin the impeller as explained in the FAQ on this site?

Tony

 

[johnscales]

Didn't at the time but just did and it's not moving freely.

Hammer and screwdriver hasn't manage to free up neither top nor bottom nut.
Any advance on my suggestion about heating them or is it a non starter?

 

[Andygasman2010]

Yes you could apply some heat.

Personally i'd just give it a whack with a hammer and chisel! Works every time with a couple of blows You do run the risk of snapping the nut though.

As already said, if you've drained it off why don't you just change the valves too?

 

[mickyg]

find it quicker to just cut the nuts off with a hacksaw and replace them.

 

[johnscales]

and the winner is..... The wife = call out an engineer.

Just found a chisel tho. Worth a try first.

 

[Agile]

Put a stout screwdriver in the impeller and tap it with a hammer and see if it will then allow it to turn.

If not then remove the four 4mm allen set screws and remove the poump head and see if you can free it up by turning teh impeller. The larger diameter is easier to apply more rotational force.

Some citric acid on the shaft will help it to free up once yo can start it to turn . Thats applied from the screw end whilst twisting the impeller.

Tony

 

[tamz]

and the winner is..... The wife = call out an engineer.

Just found a chisel tho. Worth a try first.

Your wife is a wise (and probably frozen) woman.
Put you chisel back in the cupboard and pick the phone up.

It is not hard to do this but you do need the skills. Sometimes it is better to admit defeat.

 

[johnscales]

Back again. Due to no engineers being available to help until today or Monday at the earliest i've cracked on and hack sawed the valves off so am ready to replace the pump now.
I've been to s****fix and for the junior hack saw and 2 pump valves identical to my existing valves:

http://www.screwfix.com/prods/74843/Plumbing/Brassware/Gate-Pump-Valve-22mm

Except they're 22mm and mine are 28mm. They don't list these in 28mm. Does anyone know what valves I can use which do the same job?
Obviously the length needs to be the same for fitting purposes.

thanks. Heat and hot water will be with me soon.... I hope.

 

[husker199]

I think youll have to wait till you can get to a plumbers merchants in the morning tbh.