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Post by DIYDafty on Apr 30, 2020 20:47:31 GMT
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 ? e.g. this one isn't much cheaper on ebay: www.toolstation.com/grundfos-ups3-15-5065-130-central-heating-circulating-pump/p66575What happened to the old 15-50 and 15-60 which if I recall I could never really understood why they did two pumps that looked so similar. |
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Post by cylinderfella on Apr 30, 2020 21:25:10 GMT
15/50 gives 5m head and 15/60 gives 6m head. You'd get the 6m head one to push the water further as in a big house with a load of rads. 5m head is enough for most houses.
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Post by cylinderfella on Apr 30, 2020 21:27:10 GMT
You don't have to go with the same brand either. The others on here will know the best/cheapest ones.👍
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Post by cylinderfella on Apr 30, 2020 21:31:11 GMT
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Post by DIYDafty on Apr 30, 2020 21:41:25 GMT
15/50 gives 5m head and 15/60 gives 6m head. You'd get the 6m head one to push the water further as in a big house with a load of rads. 5m head is enough for most houses. Cheers for your replies. On this point is there really much difference between 5m and 6m worth of head? Also those no-name pumps - are they as good as the grundfos? |
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Post by cylinderfella on Apr 30, 2020 21:51:36 GMT
Not really sure of the science of it DD!
I know Tom would put you straight on the quality issue, so hang on for the rest of the gang to pitch in.....
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Post by dickpuller on May 1, 2020 6:23:22 GMT
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. |
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Post by crowsfoot on May 1, 2020 6:27:26 GMT
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  ! |
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Post by crowsfoot on May 1, 2020 6:28:54 GMT
You nipped in there Dick just before me!!  |
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Post by tomplum on May 1, 2020 7:54:36 GMT
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Post by DIYDafty on May 1, 2020 15:37:07 GMT
Wow - thanks a lot for brilliant replies esp Dick for the lowdown on these pumps and Tom for the recommendation. At £29 I'm, gonna get one so I'm well prepared for when the time comes.
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Post by DIYDafty on May 5, 2020 13:29:12 GMT
Arrived today. Box is knackered but seems new. Connections look a lot smaller than existing pump. How would I connect it when the time comes?
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Post by tomplum on May 5, 2020 15:31:23 GMT
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,
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Post by DIYDafty on May 5, 2020 16:31:38 GMT
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.
Is there no way to connect on to them?
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Post by tomplum on May 5, 2020 16:48:21 GMT
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,.
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