Hi, I was hoping for your advice on something I've noticed.
My system is:
Potterton suprima 100 (fairly recent new PCB).
pump: grundfos super selectric. (set to 3)
Open vented
separate vent and feed (vent is 22mm).
two honeywell zone valves - both two way
automatic bypass (set to 2)
Problem is: when hot water is on in the morning there are splutters from the vent to the feed/expansion tank. Having observed the system what appears to happen is that the boiler turns off presumably because the water leaving the boiler is hot enough. The pump continues to run. After a while the boiler starts again- just before it does this the pump stops and restarts. When it does this there is a splutter from the vent. There is also quite a lot of banging during the period of time the hot water tank is being heated. I think the banging sounds like it could be coming from the region of wall where amongst others the feed and expansion pipe are.
I assume the same is happening when the heating is on but because the boiler turns off/on less frequently i haven't noticed it.
Known problems with the system
1) automatic air vent by boiler doesn't work (in post)
2) zone valve to hot water tank- lever does not turn although with the box off full movement of the spindle is seen and the return pipe from the hot water tank gets hot quickly (also in post)
3) pipes in loft have fairly long (3m) horizontal region and may even be slightly down hill to tank. Have had problems with air locks in both central heating and cold water systems. There may be another horizontal segment between 1st and second floors too.
I think the problem may be occurring since I put the auto bypass in and turned the pump up to 3. To get the required flow to the boiler (4.5l) it seems to me from the curves that it has to be on three.
2 questions:
1) is it normal that the pump turns off and on before the boiler relights?
2) what do you think the problem with the system is?
3) the small cylinder which takes the flow from the boiler, has the vent pipe coming out from the top and the flow to the pump near the bottom- is it more complicated than it looks of just a cylinder with three appropriately positioned outlets? and can they go wrong?
Many thanks for any advice you've got!
My system is:
Potterton suprima 100 (fairly recent new PCB).
pump: grundfos super selectric. (set to 3)
Open vented
separate vent and feed (vent is 22mm).
two honeywell zone valves - both two way
automatic bypass (set to 2)
Problem is: when hot water is on in the morning there are splutters from the vent to the feed/expansion tank. Having observed the system what appears to happen is that the boiler turns off presumably because the water leaving the boiler is hot enough. The pump continues to run. After a while the boiler starts again- just before it does this the pump stops and restarts. When it does this there is a splutter from the vent. There is also quite a lot of banging during the period of time the hot water tank is being heated. I think the banging sounds like it could be coming from the region of wall where amongst others the feed and expansion pipe are.
I assume the same is happening when the heating is on but because the boiler turns off/on less frequently i haven't noticed it.
Known problems with the system
1) automatic air vent by boiler doesn't work (in post)
2) zone valve to hot water tank- lever does not turn although with the box off full movement of the spindle is seen and the return pipe from the hot water tank gets hot quickly (also in post)
3) pipes in loft have fairly long (3m) horizontal region and may even be slightly down hill to tank. Have had problems with air locks in both central heating and cold water systems. There may be another horizontal segment between 1st and second floors too.
I think the problem may be occurring since I put the auto bypass in and turned the pump up to 3. To get the required flow to the boiler (4.5l) it seems to me from the curves that it has to be on three.
2 questions:
1) is it normal that the pump turns off and on before the boiler relights?
2) what do you think the problem with the system is?
3) the small cylinder which takes the flow from the boiler, has the vent pipe coming out from the top and the flow to the pump near the bottom- is it more complicated than it looks of just a cylinder with three appropriately positioned outlets? and can they go wrong?
Many thanks for any advice you've got!