Should I upgrade central heating pump?

[drives]

Hi all, could do with some advice...

I have a 16 radiator two pipe central heating system with a 28kw boiler- it's sealed as we've recently converted over to an unvented hot water cylinder. We have a Grundfos 15/60 130 pump in the airing cupboard.

Our present issue is that when at speed 2 it is relatively quiet, but our radiators do not get that hot, even with flow temp at 65. At speed 3, the rads all get nice and hot but the constant hum (not necessarily from the pump- moreso I'd say around where the large flow and return pipes are running underneath floorboards) is annoying.

Would we benefit from an upgraded pump such as a grundfos 'auto adapt' model at all? I'm not overly clear on how these work but if when the heating was switched on it might run at a higher speed, and then settle down to a more steady flow, that would still be of interest to us as it's just the constant hum at the top speed is rather irritating. If so, is there a particular model that would be recommended?

Thanks

 

[Madrab]

Depends on what's causing the resonance. If the pumps getting a little noisy with age then that vibration can resonate down the pipework and where it enters larger spaces can be amplified, that and what the pipework/pump may be fixed to.

Think of a guitar body amplifying sound.

 

[drives]

Ok yes thanks for the advice. I don't believe it's the pump vibrating or getting noisy as such. It is moreso that resonation down the pipework and this increases with pump speed. What the source of this is, I don't know. I was trying to get my head around how something like the Grundfos auto adapt pumps work and perhaps these would 'find' a more suitable speed rather than full throttle on 3 all the time we wanted the heating on. But...they are a bit pricey to take a punt on when I don't know if they'll actually improve our situation.

 

[Madrab]

All pumps have a certain degree of resonance to them, some louder than others and that then tends to increase and decrease with the setting. An older pump will tend to 'resonate' that bit more but that's more due to debris and accumulation on the impeller and then the pump spins slightly out of balance creating a little vibration that resonates on the pipework. Bearings can get a little bit worn etc.

 

[Johntheo5]

Hi all, could do with some advice...

I have a 16 radiator two pipe central heating system with a 28kw boiler- it's sealed as we've recently converted over to an unvented hot water cylinder. We have a Grundfos 15/60 130 pump in the airing cupboard.

Our present issue is that when at speed 2 it is relatively quiet, but our radiators do not get that hot, even with flow temp at 65. At speed 3, the rads all get nice and hot but the constant hum (not necessarily from the pump- moreso I'd say around where the large flow and return pipes are running underneath floorboards) is annoying.

Would we benefit from an upgraded pump such as a grundfos 'auto adapt' model at all? I'm not overly clear on how these work but if when the heating was switched on it might run at a higher speed, and then settle down to a more steady flow, that would still be of interest to us as it's just the constant hum at the top speed is rather irritating. If so, is there a particular model that would be recommended?

Thanks

Auto Adapt, especially on Grundfos Pumps is generally pretty useless from what I gather.

Your pump, if I am reading the correct pump curves has a huge difference in the pump heads at say a circulation flow of 1.5m3/hr which is ~ what you might require, speed 2 will only supply this at a 1.0M head and speed 3 at a 4M head, you may find that a head of 3.0/3.5M is adequate to heat all your rads.
There are plenty of pumps out there that will give you that including the Alpha 2L, I have a Wilo Yonos Pico 6M pump where you can change the constant pressure, CP and the proportional pressure, PP modes incrementally in 0.1M steps to give you any head you require, it also has the 3 "fixed speed" constant curve, CC modes, cost me around £110 three years ago.

 

[drives]

Auto Adapt, especially on Grundfos Pumps is generally pretty useless from what I gather.

Your pump, if I am reading the correct pump curves has a huge difference in the pump heads at say a circulation flow of 1.5m3/hr which is ~ what you might require, speed 2 will only supply this at a 1.0M head and speed 3 at a 4M head, you may find that a head of 3.0/3.5M is adequate to heat all your rads.
There are plenty of pumps out there that will give you that including the Alpha 2L, I have a Wilo Yonos Pico 6M pump where you can change the constant pressure, CP and the proportional pressure, PP modes incrementally in 0.1M steps to give you any head you require, it also has the 3 "fixed speed" constant curve, CC modes, cost me around £110 three years ago.

That is really useful- thanks. That does indeed seem to be part of the problem in that there appears to be a huge jump between speeds two and three. I found another pump yesterday which had a dial where you could gradually increase speed which also looked like it might be a better option ( Lowara Ecocirc).

 

[Johntheo5]

Just ensure, whatever you choose, that its a 6M pump.

 

[JonathanM]

Your pump, if I am reading the correct pump curves has a huge difference in the pump heads at say a circulation flow of 1.5m3/hr which is ~ what you might require, speed 2 will only supply this at a 1.0M head and speed 3 at a 4M head,

There are at least two versions of Grundfos 15/60 130, with very different curves. This is another version, where speeds 2 and 3 are much closer:

 

[JonathanM]

We have a Grundfos 15/60 130 pump in the airing cupboard.

Do you have the Part Number off the front of the pump? Top right probably.

 

[drives]

Do you have the Part Number off the front of the pump? Top right probably.

Thanks- I've attached a photo of the front if that helps? Incidentally I have ordered a new pump- I went for a Lowara Ecocirc which has a gradual dial adjustment rather than just three settings for the speed. Hopefully it will do the trick, and really appreciate all the advice.

 

[JonathanM]

Thanks- I've attached a photo of the front if that helps? Incidentally I have ordered a new pump- I went for a Lowara Ecocirc which has a gradual dial adjustment rather than just three settings for the speed. Hopefully it will do the trick, and really appreciate all the advice.

Your pump is the version @Johntheo5 mentioned above, No. 59526600.

If you are interested in the performance, you can see how different it is, using this chart, and the one a few posts above. On the top graph for each, the difference in output, between speeds 2 & 3 in particular, is a lot bigger in your version. Yours does seem very feeble on speeds 1 & 2! But if you use 3, it is extremely powerful.

Hopefully the new pump will use a lot less power and run more quietly.

 

[Johntheo5]

Feeble on speeds 1&2 probably because it was manufactured in week 43 1997!, not a bad run, (PC9743)

 

[drives]

Really interesting to see our pump performance in graph form and explains exactly what we are experiencing with the massive jump. And, how old it is!

Ok glad I’ve got a replacement and confident it will help a fair bit with our problem.

 

[Johntheo5]

Which one of these is it, ecocirc or ecocirc+ and a 6M?

 

[drives]

It’s the plus, and 8M.