C
cmicky
Hi, new member here, first post. Not a plumber but a keen diyer. Have installed CH & UFH in the past, not gas though, leave that to the pros. Great site love the banter.
Looking for some helpful advice
2yrs ago we had a company in to install a 30 tube solar hot water system. They replaced our old indirect small HW cylinder with a Gledhill Torrent 210L direct OV solar thermal store. They reckoned our existing Gloworm 18HXI boiler and Grundfos alpha2L 15-60 pump, Y plan and ABV would be fine to leave in place. Solar works fine, boiler hardly on in the summer, loads of free hot water, great!
Then there soon appeared a problem. The boiler started to make a banging and loud helicopter type noises. Called the firm back and they suggested it was a scaled up heat exchanger. As it was ok before the install, they decided to remove the Hex and do a local flush on their machine. This improved it slightly, but did not stop the noises. So, back they came added 4 cans of Sentinel X800 and told me to leave it in for a few weeks. I was surprised at 4 cans, but I do have 10 rads, 100m of UFH and a 210L thermal store
In the meantime we had our annual BG homecare visit. The engineer checked the gas rate and co2 were ok, then said the Hex was buggered and needed replacing, would cost £350 + labour on top! Apparently its not covered by our plan!
Tried to get the company back to drain, flush and refill the system, but they were always too busy doing other installs that summer. So as I was no longer getting replies from them I decided to do it myself. Drained, flushed 3 times and then added the required qty of inhibiter. Still the same!
It then really began to get into my head it was a flow restriction problem, as there appeared to be localised boiling even on pump speed 3. The pipe work did look complicated around the store. Gledhill say the boiler stat should be on max and the store stat at 70c. Our boiler could never go over 65c without knocking, so the store stat had to set at 60c. The return temp would follow behind the flow by 12c, right up until the store stat turned off the boiler.
I then decided to rip out the pipe work and many elbows to the store, dump the motorised valve and ABV. I then plumbed a more direct route to the store in 22mm with a lot fewer fittings, used a separate 6m 3 speed pump, and the existing alpha on the CH side,As per the Gledhill info.
No change, so had the Hex replaced and a spyrotrap fitted. Knocking still there! Wasted my time and money there then!
So chaps, I have no idea how to size a pump, the question IS my boiler pump undersized, boiler too big or some thing else.
My system comprises of
Gloworm 18HXI. 1.38m@774Lhr delta 20c head loss, on ground floor
Gledhill torrent 210L direct RE solar OV on first floor
22mm Spyrotrap on boiler return
DAB 65-130 pumping out of store return to boiler
10m of 22mm pipe from boiler to store
Store boiler flow and return approx 1m apart
2m static head ( Am I right to believe it is pump to water level in F&E)
Cheers
Looking for some helpful advice
2yrs ago we had a company in to install a 30 tube solar hot water system. They replaced our old indirect small HW cylinder with a Gledhill Torrent 210L direct OV solar thermal store. They reckoned our existing Gloworm 18HXI boiler and Grundfos alpha2L 15-60 pump, Y plan and ABV would be fine to leave in place. Solar works fine, boiler hardly on in the summer, loads of free hot water, great!
Then there soon appeared a problem. The boiler started to make a banging and loud helicopter type noises. Called the firm back and they suggested it was a scaled up heat exchanger. As it was ok before the install, they decided to remove the Hex and do a local flush on their machine. This improved it slightly, but did not stop the noises. So, back they came added 4 cans of Sentinel X800 and told me to leave it in for a few weeks. I was surprised at 4 cans, but I do have 10 rads, 100m of UFH and a 210L thermal store
In the meantime we had our annual BG homecare visit. The engineer checked the gas rate and co2 were ok, then said the Hex was buggered and needed replacing, would cost £350 + labour on top! Apparently its not covered by our plan!
Tried to get the company back to drain, flush and refill the system, but they were always too busy doing other installs that summer. So as I was no longer getting replies from them I decided to do it myself. Drained, flushed 3 times and then added the required qty of inhibiter. Still the same!
It then really began to get into my head it was a flow restriction problem, as there appeared to be localised boiling even on pump speed 3. The pipe work did look complicated around the store. Gledhill say the boiler stat should be on max and the store stat at 70c. Our boiler could never go over 65c without knocking, so the store stat had to set at 60c. The return temp would follow behind the flow by 12c, right up until the store stat turned off the boiler.
I then decided to rip out the pipe work and many elbows to the store, dump the motorised valve and ABV. I then plumbed a more direct route to the store in 22mm with a lot fewer fittings, used a separate 6m 3 speed pump, and the existing alpha on the CH side,As per the Gledhill info.
No change, so had the Hex replaced and a spyrotrap fitted. Knocking still there! Wasted my time and money there then!
So chaps, I have no idea how to size a pump, the question IS my boiler pump undersized, boiler too big or some thing else.
My system comprises of
Gloworm 18HXI. 1.38m@774Lhr delta 20c head loss, on ground floor
Gledhill torrent 210L direct RE solar OV on first floor
22mm Spyrotrap on boiler return
DAB 65-130 pumping out of store return to boiler
10m of 22mm pipe from boiler to store
Store boiler flow and return approx 1m apart
2m static head ( Am I right to believe it is pump to water level in F&E)
Cheers
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