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central heating pumps

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chrismpw said:
Any heating engineers on here?

Our house has a Grundfoss circulation pump, condensing boiler, hot water tank and radiators on two floors - the system is open vented. Trouble is the pump is rammed to the back of the airing cupboard and the settings switch has been accidentally pushed a few times. I noticed this when it wakes me up in the early hours as it's currently set to full chat - around 40W - and it never used to.

So I'm experimenting with different speeds starting with low flow (using the wife's whinging to tell me when its too cold).

What I'm wondering is - what basis does the auto setting use to adjust to? (I tried this for a couple of days and the moaning increased (moaning by text as I was away at the time obvs)).

To the right, if I keep pressing the settings button - it goes onto increasing pressure. What's the difference between increasing pressure (on the right) and increasing flow (on the left) in terms of finding the sweet spot to transfer heat from our boiler to the radiators and tank?

And yes I've tried rice and sawdust.
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Are you insured ? My mother in law's pump went & Saga insurance have a homes' repair policy - engineer came out fixed it temporary then ordered a new one & replaced it free of charge .....check your household policy ....
 
Joey66 said:
Are you insured ? My mother in law's pump went & Saga insurance have a homes' repair policy - engineer came out fixed it temporary then ordered a new one & replaced it free of charge .....check your household policy ....
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I don't insure for that kind of thing because I generally can fix or service those things I can legally tamper with. There's nothing wrong with the pump - I just can't figure the correct setting. Well in time with experimentation I can, its just that with the current profiteering of the energy companies ... sorry... "rise in costs" and the missus moaning because she's inactive.... sorry, "cold" I was hoping for a quicker solution.
 

chrismpw said:
I don't insure for that kind of thing because I generally can fix or service those things I can legally tamper with. There's nothing wrong with the pump - I just can't figure the correct setting. Well in time with experimentation I can, its just that with the current profiteering of the energy companies ... sorry... "rise in costs" and the missus moaning because she's inactive.... sorry, "cold" I was hoping for a quicker solution.
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Pump sounds like it's on its way out - have you tried YouTube?
 
chrismpw said:
I don't insure for that kind of thing because I generally can fix or service those things I can legally tamper with. There's nothing wrong with the pump - I just can't figure the correct setting. Well in time with experimentation I can, its just that with the current profiteering of the energy companies ... sorry... "rise in costs" and the missus moaning because she's inactive.... sorry, "cold" I was hoping for a quicker solution.
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TLDR?


I'm an arl tight arse and she won't put a feckin jumper on
 

tim gabbott said:
Just set it half way.
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This ^ The only change you are making by using the controls is making the pump spin faster / slower.

Flow, pressure and energy consumption are all related to pump speed. Flow rate is directly proportional to speed, pressure has a square law relationship and power cube.

Basically if you double the pump speed, you’ll get roughly twice the flow, a shed load more pressure and tons more energy consumption.

The lower the speed you can get away with, the quieter the system will be.

As you have a condensing boiler, a higher pump speed will potentially affect (lower) the efficiency of the boiler. Ideally the temperature of the water returning to the boiler from the radiators should be no greater than 55 C or it won’t be doing any condensing.

The pump auto functions can have all sorts of sexy settings to accommodate the changes in your system if you have thermostatic control valves on your rads. There will never be a single ideal speed setting, as the valves will constantly be changing position in different rooms. The correct auto setting compensates for this.

Set it half way.
 
Haydn said:
This ^ The only change you are making by using the controls is making the pump spin faster / slower.

Flow, pressure and energy consumption are all related to pump speed. Flow rate is directly proportional to speed, pressure has a square law relationship and power cube.

Basically if you double the pump speed, you’ll get roughly twice the flow, a shed load more pressure and tons more energy consumption.

The lower the speed you can get away with, the quieter the system will be.

As you have a condensing boiler, a higher pump speed will potentially affect (lower) the efficiency of the boiler. Ideally the temperature of the water returning to the boiler from the radiators should be no greater than 55 C or it won’t be doing any condensing.

The pump auto functions can have all sorts of sexy settings to accommodate the changes in your system if you have thermostatic control valves on your rads. There will never be a single ideal speed setting, as the valves will constantly be changing position in different rooms. The correct auto setting compensates for this.

Set it half way.
Click to expand...
This is the sort of brain dust I was after! Cheers! I've been trying to envisage how flow related to efficiency - and how often the boiler fired up or shut off.

So the auto setting figures itself out. I kind of hoped it would but this setting is where the missus started her heat canary chirping. Perhaps I'll try the auto and up the temperature setting of the boiler to half way. (For ages I reckon the pump has been on max and the boiler been turned down, but there are some rooms that barely see the heat.
 

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