I'm sorry to revisit my thread but the hot water issue continues. Main boiler PCB replaced and pump thoroughly checked; no change in this issue. Tonight I stayed with the boiler for 50+ minutes to document the hot water scenario.
Times are stop watch mins/secs............
0.00 15 degrees pump fired straight up and ran consistently and quietly throughout.
3.00 Steady climb to to around 60 degrees then all over the place, back to 30, hovered and then climbed quickly
3.45 cut out at 72 degrees
4.22 fired up at 62
5.20 cut out at 72
5.50 fired up at 55
6.04 cut out at 72
6.36 fired up at 55
7.00 cut out at 72
7.22 fired up at 53
8.20 cut out
8.51 fired up
9.12 cut out
9.43 fired up
10.01 cut out
10.32 fired up
10.55 cut out
11.24 fired up
12.21 cut out(settling)
16.00 54
18.00 52
22.00 50
25.00 49
32.20 48
39.30 47
49.00 46 fired up
51.15 72 cut out
Steady drop as before(stabilized)
To summarise the boiler and pump appear to be working perfectly. The problem is that the circulating water is initially heating up and cooling down too quickly, hence the nine fire ups and cut outs where there would ideally be just one. Boiler and hot water tank were installed in 2006. There is very little hard water deposit down here in South Devon but it seems to me that the issue may be a failure of the heat to effectively transfer from the coil system in the tank to the contents. I think this is causing the limited boiler heated circulatory water to have very unstable temperature until the hot water tank contents finally get up to temperature and stop a fast cooling of the circulating water. The Grundfos 16/60, 130 pump(pic earlier in thread) is set to speed three(of three). Quite a lot of radiators in the house so works well for central heating. Perhaps the hot water system with small 114 litre tank would work better if the pump was set at one or two? If anyone can think of anything else, input much appreciated.
Times are stop watch mins/secs............
0.00 15 degrees pump fired straight up and ran consistently and quietly throughout.
3.00 Steady climb to to around 60 degrees then all over the place, back to 30, hovered and then climbed quickly
3.45 cut out at 72 degrees
4.22 fired up at 62
5.20 cut out at 72
5.50 fired up at 55
6.04 cut out at 72
6.36 fired up at 55
7.00 cut out at 72
7.22 fired up at 53
8.20 cut out
8.51 fired up
9.12 cut out
9.43 fired up
10.01 cut out
10.32 fired up
10.55 cut out
11.24 fired up
12.21 cut out(settling)
16.00 54
18.00 52
22.00 50
25.00 49
32.20 48
39.30 47
49.00 46 fired up
51.15 72 cut out
Steady drop as before(stabilized)
To summarise the boiler and pump appear to be working perfectly. The problem is that the circulating water is initially heating up and cooling down too quickly, hence the nine fire ups and cut outs where there would ideally be just one. Boiler and hot water tank were installed in 2006. There is very little hard water deposit down here in South Devon but it seems to me that the issue may be a failure of the heat to effectively transfer from the coil system in the tank to the contents. I think this is causing the limited boiler heated circulatory water to have very unstable temperature until the hot water tank contents finally get up to temperature and stop a fast cooling of the circulating water. The Grundfos 16/60, 130 pump(pic earlier in thread) is set to speed three(of three). Quite a lot of radiators in the house so works well for central heating. Perhaps the hot water system with small 114 litre tank would work better if the pump was set at one or two? If anyone can think of anything else, input much appreciated.
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