I'm soon to be dicking around in the airing cupboard to replace a MV valve and add a new MV for a new zone. Existing CH pump is a grundfos and looks like its been there pumping magnatite and a bit of water round the system since before I was born. I'm not going to replace it unless it fails but want to be in a good position if it does and even thinking about buying one to keep for the occasion.
Anyway, I occasionally look at prices and I could have sworn that say a year ago you could get a new Grundfos for about £60. Now, its seems I'd be looking at a hundred ?
Most Grunny circulation pumps are bullet proof. I did some photos on ‘cleaning the can’ on these & thought I posted them on ear???!! I must try & find them for you Dafty.
Anyrode, the circulation pump in the above link is a ‘smart pump’, this adjusts its speed according to the resistance in the system. These are also called ERP pumps, but, that’s EU nonsense & as we’re out of that shower of shite, ignore that. Remember Brexit?? That was a life or death debate before a life & death Pandemic came our way!!!
You currently have a ‘fixed head’ circulation pump & you want to hold onto it as long as possible. Smart Pumps can be a PITA, as they slow down & stop if there’s little or no circulation. You can easily stop the impeller from turning with the palm of your hand. Smart Pumps are shite on older systems.
From a Controls prospective, PWM is used to control the speed of ERP pumps in a Combi(condensing) boiler for example; where the on-board circulation pump is used, not only, for system circulation, but controls the temperature in the boiler, to try to have it in the condensing mode as long as possible.
Sir Richard Puller MBE cultural attaché for Glasgow to the court of St James.
I don't fit many pumps at all these days, however, at one time it was a bread and butter job for me.
I heard somewhere that all new pumps now have to be self modulating so they should be able to measure the resistance of the index radiator circuit and adjust to this automatically without the tradesman having to adjust the speed of the pump.
Perhaps this is the reason for that large increase in price !
the connections were the same on the ones I Got DD, I've had at least 4 off them and all was just a swap over, they either changed supplier or its a different type, Sent it back DD as wrongly describedas its not a 'universal central heating' pump. Because its not as described they will send you a paid returns label to stick on your package,
I think the problem might be the picture does show the smaller connectors. I might try but I sell on ebay too and I don't like when customers are in the wrong but I still have to refund. I'll have a think.
I've looked at some of the other pumps and some show adapters supplied with the pumps, Come to think of it, 2 of the pumps I bought had those adapters but I did't need them because the pumps fitted straight out of the boxes, I'll see if I can dig one out, if i do, that might make your pump fit, give me an hour and I'll find one at take a pic,.