N
namsag
So the sliced bread boiler lasted less than a month. 
Central heating: What circulation flow rate?
- Thread starter JohnD
- Start date
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N
namsag
Don`t envy you having a boiler like a woman john. Talk about tempramental. I`m quite lucky just now as she isn`t talking to me. Ah the peace and quiet is lovely
Had a mate once who said he was divorcing his wife because she had not spoke to him for 3 months.
I told him don`t be too hasty a woman like that is hard to find
Had a mate once who said he was divorcing his wife because she had not spoke to him for 3 months.
I told him don`t be too hasty a woman like that is hard to find
That should cope with virtually any installation, so there is no chance you pump is undersized.
But he has proved that the Spirovent is not the cause of the problem! He has probably never seen one before, doesn't know what they are supposed to do, doesn't know how they work. Obvious solution - blame the unknown!
The Alpha+ 15-60 will deliver 0.3 litres/sec against a dynamic head of 4.5 metres; I would be surprised if yours was that high.
Do you have a bypass valve between flow and return? The bypass valve should be adjusted with the pump on lowest fixed speed (1 o'clock). Set the pump to constant pressure (11 o'clock) for normal use.
I guess you have TRVs on your rads. Have you balanced the system? It still needs to be done, even with TRVs and may affect the pump setting.
The best instructions are Balancing TRVs. Although they refer to Drayton TRVs, they are very easy to follow. However, I would ignore the bit where they recommend using a decorators cap to hold a TRV partly open - everyone else recommends balancing the system with the head right off, so the valve is full open. Set the pump to a fixed speed (I, II or III) while balancing.
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it does not have a bypass. I wondered about this and asked Viessmann, their tech desk tell me it is not required. the pump runs on for ten mins after it has stopped firing, and the 3-port valve stays open at whatever setting it was on when the stats stopped calling for heat.
the syst is already very clean and not sludgy (I had been trying to cure the old bonking boiler a few months ago). It was powerflushed before fitting the new boiler but the magnets picked up very little.
yes, it has TRV4s and I had balanced it on the old boiler. All TRVs have been wound up to max so they should all be open (temp here is about 24C at the moment). I have two rads without TRVs
the flow sensor claimed insufficient flow even with both heat and HW on. the cylinder flow does not have a lockshield but is necked down to 15mm for about 300m at the cylinder. It is right next to the pump and 3-port valve.
it does not have a bypass. I wondered about this and asked Viessmann, their tech desk tell me it is not required. the pump runs on for ten mins after it has stopped firing, and the 3-port valve stays open at whatever setting it was on when the stats stopped calling for heat.
the syst is already very clean and not sludgy (I had been trying to cure the old bonking boiler a few months ago). It was powerflushed before fitting the new boiler but the magnets picked up very little.
yes, it has TRV4s and I had balanced it on the old boiler. All TRVs have been wound up to max so they should all be open (temp here is about 24C at the moment). I have two rads without TRVs
the flow sensor claimed insufficient flow even with both heat and HW on. the cylinder flow does not have a lockshield but is necked down to 15mm for about 300m at the cylinder. It is right next to the pump and 3-port valve.
One problem area discounted!
Did you balance with the TRVs on max or with the tops removed? It's more accurate with the tops right off.
But the flow sensor was faulty; has it been replaced yet and are you still getting the problem?
Could there be another valve in the system which has been left partly closed?
How old is the mid-position valve? Could it be obstructing the flow - ball problems etc.
What happens if you open all TRVs and lockshield valves to max (write down their settings)?
TRVs are a few months old. I balanced with the tops on and open.
3port valve is new, as are pump and gate valves, room and cyl stat, programmer, boiler
no other valves
installer will be back in a day or so with new flow sensor. Boiler is out of use until then. My opinion is currently that the problem was caused by flow sensor and I expect that the new sensor will solve it.
3port valve is new, as are pump and gate valves, room and cyl stat, programmer, boiler
no other valves
installer will be back in a day or so with new flow sensor. Boiler is out of use until then. My opinion is currently that the problem was caused by flow sensor and I expect that the new sensor will solve it.
Please post the results of changing the flow sensor.
D
Deleted member 105431
this might sound bloody obvious but have you checked the pump is in the correct direction?
interesting to see the "bullet proof" viessman suffer failures too.
interesting to see the "bullet proof" viessman suffer failures too.
dangermouse wins todays star prize and scores one million Higgs-Boson particles
Circulation was going the wrong way round the boiler and pushing the flow sensor the wrong way
boss is blaming the junior who took up the upstairs floor and joined to the old pipes.
as the floor was then put down again, and WC and basin refixed, it was not obvious that the pipes had been mis-connected until boiler was fired up again and we felt the pipes (he had put pipe thermometers on, but it was very easy to tell by hand)
I wonder if I should be asking for a cash reduction by way of compensation.
Circulation was going the wrong way round the boiler and pushing the flow sensor the wrong way
boss is blaming the junior who took up the upstairs floor and joined to the old pipes.
as the floor was then put down again, and WC and basin refixed, it was not obvious that the pipes had been mis-connected until boiler was fired up again and we felt the pipes (he had put pipe thermometers on, but it was very easy to tell by hand)
I wonder if I should be asking for a cash reduction by way of compensation.
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