Hi, think we have a flow rate problem in our central heating....but don't know how to tackle it..
We've an old CH system, which was installed before we moved in 16 years ago...and to be honest not well serviced, but has never let us down. BAXI boiler and expansion tank in loft, that feed a pump and HW tank in an airing cupboard below.
The boiler, or surrounding pipes, have been a bit clonking when it first fires up, and on one occasion I saw steam or air spluttering up out of higher expansion tank.
But we always have plenty of hot water in the tank and pipes.
We extended the house around 12 years ago and now have 11 radiators.
The main issue at preset is that more and more across the last couple of winter seasons, many of the rads would not get hot.
I did all I could to balance them. But unless i closed all but the further ones...I could not get heat to them at all.
Back up stairs the pump would be whirring away...and the pipes either side of it red hot, and likewise both the A & B feeds after the 3-port valve.
I wasn't convinced the old analogue room thermostat was effectively clicking on/off...so replaced that with a Honeywell digital one.
That didnt make much difference, but at least I have accurate readings and a reliable switch now
The Grundfos 15-50 pump was a bit rumbly at times, and only smoothed out when I turned it up to speed 3 (it had previously always lived on 2). Then I noticed only 3 would work at all, and I could just hear and feel it purring, but turned back to 2 or 1 ...and nothing.
So i assumed the old pump was on its last legs and couldn't cope pushing all over the extended house.
I installed a brand new UPS2 15-50/60, which purrs on all speeds - and has an 'intelligent' setting too.
But cranking up the new thermo to really high - and with the pump on its top speed...slowly, slowly, painfully slowly ...over an hour or two heat gets to the rads.
That said we still can never get above 21'c (even if say, 23'c is chosen...not that we tend to need to, but it does seem to have a limit around 21')
Some are by then red hot - some still only tepid...so I continue to try and balance, by notching up and down the lock-shield valves (we have no TRVs) ....but so easily can one quarter turn seemingly send another once hot rad, completely cold
....and the wait for a warm house is always sooo slow.
I wondered about the 3-port valve. But the A & B pipes either side are red hot, and when powered off the little auto lever does offer motor resistance and spring back....which I was told was the first obvious check that its working ok.
Is it all fighting against some sort of blockage somewhere ? ....when I've taken rads off for decorating, we get dirty water of course....but not sludge or filth you would associate with enough build up to block, and clear water when bled from the top...but the system has not been flushed.
So, what can you suggest please....
I may have an old boiler (and cant really afford to replace that at present)...but stacks of hot water in the boiler and pipes...and a brand new UPS motor next to it whirring away (which I'm worried is overworking to the extent that killed the last one)
.....which takes an hour or so to just (just) get 20'c+ heat to the thermostat in the hall, and leaving radiators still very varied around the house, despite all efforts to balance them.
It just seems to lack a decent flow rate.
I turned the heating off earlier...in order to see if the B pipe off the 3-port valve stayed hot, suggesting it may be jammed open towards HW. That bizarrley seemed to lead to the tank running out of water when my daughter filled a bath. The hot tap didnt run cold, when it ran out...it stopped running water. The tank seemed empty. Not something I've ever experienced. I put the HW back on...and after a splutter of air, hot taps later returned to normal business.
....any ideas please
thanks
Neil
We've an old CH system, which was installed before we moved in 16 years ago...and to be honest not well serviced, but has never let us down. BAXI boiler and expansion tank in loft, that feed a pump and HW tank in an airing cupboard below.
The boiler, or surrounding pipes, have been a bit clonking when it first fires up, and on one occasion I saw steam or air spluttering up out of higher expansion tank.
But we always have plenty of hot water in the tank and pipes.
We extended the house around 12 years ago and now have 11 radiators.
The main issue at preset is that more and more across the last couple of winter seasons, many of the rads would not get hot.
I did all I could to balance them. But unless i closed all but the further ones...I could not get heat to them at all.
Back up stairs the pump would be whirring away...and the pipes either side of it red hot, and likewise both the A & B feeds after the 3-port valve.
I wasn't convinced the old analogue room thermostat was effectively clicking on/off...so replaced that with a Honeywell digital one.
That didnt make much difference, but at least I have accurate readings and a reliable switch now
The Grundfos 15-50 pump was a bit rumbly at times, and only smoothed out when I turned it up to speed 3 (it had previously always lived on 2). Then I noticed only 3 would work at all, and I could just hear and feel it purring, but turned back to 2 or 1 ...and nothing.
So i assumed the old pump was on its last legs and couldn't cope pushing all over the extended house.
I installed a brand new UPS2 15-50/60, which purrs on all speeds - and has an 'intelligent' setting too.
But cranking up the new thermo to really high - and with the pump on its top speed...slowly, slowly, painfully slowly ...over an hour or two heat gets to the rads.
That said we still can never get above 21'c (even if say, 23'c is chosen...not that we tend to need to, but it does seem to have a limit around 21')
Some are by then red hot - some still only tepid...so I continue to try and balance, by notching up and down the lock-shield valves (we have no TRVs) ....but so easily can one quarter turn seemingly send another once hot rad, completely cold
....and the wait for a warm house is always sooo slow.
I wondered about the 3-port valve. But the A & B pipes either side are red hot, and when powered off the little auto lever does offer motor resistance and spring back....which I was told was the first obvious check that its working ok.
Is it all fighting against some sort of blockage somewhere ? ....when I've taken rads off for decorating, we get dirty water of course....but not sludge or filth you would associate with enough build up to block, and clear water when bled from the top...but the system has not been flushed.
So, what can you suggest please....
I may have an old boiler (and cant really afford to replace that at present)...but stacks of hot water in the boiler and pipes...and a brand new UPS motor next to it whirring away (which I'm worried is overworking to the extent that killed the last one)
.....which takes an hour or so to just (just) get 20'c+ heat to the thermostat in the hall, and leaving radiators still very varied around the house, despite all efforts to balance them.
It just seems to lack a decent flow rate.
I turned the heating off earlier...in order to see if the B pipe off the 3-port valve stayed hot, suggesting it may be jammed open towards HW. That bizarrley seemed to lead to the tank running out of water when my daughter filled a bath. The hot tap didnt run cold, when it ran out...it stopped running water. The tank seemed empty. Not something I've ever experienced. I put the HW back on...and after a splutter of air, hot taps later returned to normal business.
....any ideas please
thanks
Neil
