Can WD40 be used to free a seized Central Heating Water Pump?

[Old Sparky]

The pump in question is fitted in a Vaillant Combination Boiler, and, whilst a new one should arrive and be fitted by Monday Afternoon, I wondered whether WD40 could be used to free up the bearings in the old one. Anyone know?

[ex 2 Base]

I'm not familiar with your boiler or circulator, but usually there is a small screw for venting and if you remove it with it pump turned OFF, then using a long small screw driver, one can often rotate the impeller very slightly enough to free things up and get it rotaing once again. I've done this several times in the past for neighbours. Its not always very easy to gain access.Best of luck.Ted

[ed731pdh]

No. If it's that badly worn then no amount of lube will keep it running for any meaningful length of time.

[pwdrive]

The CH pump in my system is a standard Grundfoss, it's an old one, I have no idea how old it is, it was in the old system when we bought the house, it seemed to work ok so I incorporated into my new system, the large slotted screw on the back is normally a bleed screw, the pump should be bled once in a while, if not air pockets can form around the bearings, the bearings don't like running in air, they are designed to run in water, bearings running in air for prolonged periods can do the bearings in.
If the bearing has seized it's worth while investigated the system as to why, however nothing lasts forever, I fitted isolating valves either side of the flow and return ports on mine so in any event the pump can be removed/replaced.

Lawrence.

[Yorkie]

The impeller runs in water in a ceramic bearing (a bush actually). It won't be seized solid but it will stall - often when the pump isn't used in summer months and the heating is switched on in autumn. The pump will be easy to dismantle but be warned - the screw which holds the impeller in place is a left-hand thread so you need to remove it by turning the screw clockwise. If you try to remove it by twisting anti-clockwise it will snap like a carrot. The pump doesn't have a 'motor' as such and apart from the impeller the pump has no moving parts - it works by induction. You simply remove the four securing screws of the pump head (the electrical part of the pump) and lift it off. You can't open that up - it isn't serviceable and they rarely fail.

You'll find that the inside of the pump including the impeller and ceramic bush are covered in a black substance which you can't successfully remove except by ultrasonics. (It's just a thin layer deposited on the impeller, shaft and bush).

You might be able to clean up the pump and get it to spin, but really, they're not such an expensive item, are easy enough to change yourself unless (as is often the case), the service valves are seized and a drain down is called for, that it's hardly worth the effort. If you get five to seven years out of a pump that's about par for the course. You might get a pump to run again after attempts at cleaning up the shaft, bush and impeller, but probably not for more than a month or two.

As to WD40, it's is a water displacement product, pretty well hopeless for freeing seized items, which WD40 seem to have acknowledged themselves by introducing a penetrating fluid to rival the likes of Plus Gas. WD40 has high surface tension - the opposite of what is needed for a penetrating fluid. I've lost count of the number of posts I've seen in forums saying 'I've soaked this in WD40 and it's still seized'. (Why would it not still be seized)?

Rambling off - as I'm prone to do - but relevant to the chances of fettling up a seized pump, in a former 'life' (from 1978 - 1990) I was Service Manager for BG at Sheffield where I set up a refurbishing workshop to re-cycle components used on central heating systems on Service contracts (and power tools such as electric drills used by installation engineers, and a PAT testing set-up). it was a mini assembly line - the pumps were stripped, placed in the ultrasonic bath where the various items came out sparkling, were stacked for reassembly later with no attempt to 'pair up' the items from each disassembled pump. (The pump bodies were re-sprayed and put in one rack, impellers in another, bearings in this box etc.

Though the refurbished pumps were reliable, it was a marginal operation as BG bought so many new pumps anyway that they got them so cheaply, so it was hardly worth the effort to furtle about with old ones. As much as anything, it was to keep older service engineers with long service who were not in good health, in a job, back in those quaint old days when such considerations as long service, employee loyalty and welfare considerations still held sway. When I came to Hull as General Manager in 1991, one of my first tasks was to present 50, 40 and 25 year awards, of which there were scores in attendance. Three years later I was presented with my own 40 yr award, whereupon I sank gently to earth is a 'golden parachute' and have spent the last 19 years sucking the life out of the BG final salary pension scheme, (long since closed to new entrants). It is my heart's desire to continue to do so in perpetuity.

How times change!

Rambled and waffled Yorkie.