Hi everyone,
I'm hoping somebody may be able to help with this problem as I've spent all of today trying to sort it!
System is open vented CH with gravity fed DHW - there is an Ideal Mexico boiler with separate cylinder in utility room with header tanks for CH and DHW in the loft.
Basically in my parents house the central heating system started performing really poorly in the winter of 2009, they lived with it as the problem wasn't that bad at the time. System of course got left unused during the following year and last winter when they came to use the system it was terrible. Rad's upstairs hardly got warm and the one's downstairs got relatively hot but not like they used to be. Over Christmas we drained the CH system, filled it with Fernox F3 and left it for a couple of weeks. I went back just after Christmas, helped drain the system down again - water seemed clear - and re-filled with Fernox corrosion inhibitor. Afterwards performance seemed to improve somewhat with the downstairs rad's getting hot and upstairs getting warm. Not perfect but it saw them through the winter.
Anyway, in my infinite wisdom (read - spending way too much time online) I decided that the CH pump was probably on it's last legs, it was the original pump installed with the system around 20 years ago, and so decided to replace it.
Originally there was a Grundfos 15-50 in place and I ordered the same to replace it. It came about a month ago but we only got round to fitting today.
I shut off the water outside, turned the boiler off, turned off the mains supply to the timer switch and then shut the valves either side of the pump. Went to remove it only to find that one of the valves wasn't shutting properly. After around 2 bucketfuls of water the water had drained enough for me to remove the old pump. The bottom valve was COMPLETELY silted up with black stuff - how water still flowed through I don't really know! I spent a good hour cleaning it all out (didn't have another valve) and all was good. It seemed the only part silted was the valve and looking down the pipe it all looked ok.
I removed the new pump from the box only to find I had been sent a Grundfos 15-60 instead on the 15-50. After checking online I decided this pump would be ok for the job, that and the fact I couldn't put the old one back as the seals either side were completely destroyed. I fitted it, wired it up, switched the water back on and fired up the CH system. Everything worked perfectly, I bled a small amount of air from the pump and went and checked and bled all the rads (although no air trapped in any even though I lost 2 bucketfuls) - success! - all rads piping hot and everything back to normal again.
Tidied up, went to wash hands and realised no hot water! Went back and checked everything, all seemed to be ok but still no hot water. I don't really know what to think now and feel a bit foolish for ever attempting to swap this pump. When you turn the hot taps on in the house you occasionally seem to hear rushing air noises from the pipework by the boiler and cylinder. When you run the HW the level drops in the loft tank and the tank starts re-filling but no water is being heated. The boiler isn't kicking in to heat it would seem.
Now, I'm not sure what to think. The DHW was working fine before I attempted this pump change. I was under the impression that the CH and DHW were completely separate from each other. I am thinking that it MIGHT be a stuck motorised valve as described in the FAQ's. I know in the past my father has had to have one of them (DHW) replaced on a couple of occasions. I tried moving the slider to manual but couldn't - I think the part has been replaced at some point and has been bodged. The plastic slider seem stuck in one position. Could it just be coincidence and this is the problem or am I missing something. There doesn't seem to be any air in the system as the taps run free of any air and I attempted to free any air locks as described in posts I had seen on this forum.
I am at my wits end and am beginning to have a real dislike of the entire system
As it stands my parents now have great CH but no DHW!
Sorry for the long winded post but please can anyone help??
Thanks
-Will
I'm hoping somebody may be able to help with this problem as I've spent all of today trying to sort it!
System is open vented CH with gravity fed DHW - there is an Ideal Mexico boiler with separate cylinder in utility room with header tanks for CH and DHW in the loft.
Basically in my parents house the central heating system started performing really poorly in the winter of 2009, they lived with it as the problem wasn't that bad at the time. System of course got left unused during the following year and last winter when they came to use the system it was terrible. Rad's upstairs hardly got warm and the one's downstairs got relatively hot but not like they used to be. Over Christmas we drained the CH system, filled it with Fernox F3 and left it for a couple of weeks. I went back just after Christmas, helped drain the system down again - water seemed clear - and re-filled with Fernox corrosion inhibitor. Afterwards performance seemed to improve somewhat with the downstairs rad's getting hot and upstairs getting warm. Not perfect but it saw them through the winter.
Anyway, in my infinite wisdom (read - spending way too much time online) I decided that the CH pump was probably on it's last legs, it was the original pump installed with the system around 20 years ago, and so decided to replace it.
Originally there was a Grundfos 15-50 in place and I ordered the same to replace it. It came about a month ago but we only got round to fitting today.
I shut off the water outside, turned the boiler off, turned off the mains supply to the timer switch and then shut the valves either side of the pump. Went to remove it only to find that one of the valves wasn't shutting properly. After around 2 bucketfuls of water the water had drained enough for me to remove the old pump. The bottom valve was COMPLETELY silted up with black stuff - how water still flowed through I don't really know! I spent a good hour cleaning it all out (didn't have another valve) and all was good. It seemed the only part silted was the valve and looking down the pipe it all looked ok.
I removed the new pump from the box only to find I had been sent a Grundfos 15-60 instead on the 15-50. After checking online I decided this pump would be ok for the job, that and the fact I couldn't put the old one back as the seals either side were completely destroyed. I fitted it, wired it up, switched the water back on and fired up the CH system. Everything worked perfectly, I bled a small amount of air from the pump and went and checked and bled all the rads (although no air trapped in any even though I lost 2 bucketfuls) - success! - all rads piping hot and everything back to normal again.
Tidied up, went to wash hands and realised no hot water! Went back and checked everything, all seemed to be ok but still no hot water. I don't really know what to think now and feel a bit foolish for ever attempting to swap this pump. When you turn the hot taps on in the house you occasionally seem to hear rushing air noises from the pipework by the boiler and cylinder. When you run the HW the level drops in the loft tank and the tank starts re-filling but no water is being heated. The boiler isn't kicking in to heat it would seem.
Now, I'm not sure what to think. The DHW was working fine before I attempted this pump change. I was under the impression that the CH and DHW were completely separate from each other. I am thinking that it MIGHT be a stuck motorised valve as described in the FAQ's. I know in the past my father has had to have one of them (DHW) replaced on a couple of occasions. I tried moving the slider to manual but couldn't - I think the part has been replaced at some point and has been bodged. The plastic slider seem stuck in one position. Could it just be coincidence and this is the problem or am I missing something. There doesn't seem to be any air in the system as the taps run free of any air and I attempted to free any air locks as described in posts I had seen on this forum.
I am at my wits end and am beginning to have a real dislike of the entire system
As it stands my parents now have great CH but no DHW!Sorry for the long winded post but please can anyone help??
Thanks
-Will
