L
layman1
Hi All,
first i will describe my current system. I have a standard sundial W plan system in conjunction with a standard boiler, an indirect open vented hot water tank and single pump. the HW tank is small (90L), but has a fast recover coil. to maximise the use/efficiency of this tank am told that the boiler water temperature should be set to the maximum, however this is way too hot to be circulating around the heating circuit with small people in the house.
I'm considering getting a plumber in to rearrange pipework slightly but would like some considered opinions first. please don't suggest replacing the whole lot with combi / unvented etc etc etc.
My thoughts are that i need a motorised blending valve such as the ESBE VRG130 with thermostat on the flow line of the central heating circuit to reduce the flow temperature available to something more like 60 celsius by blending with the cooler return line. however, looking at the suggested schematics from ESBE this must be in place BEFORE the pump - which makes perfect sense as it has to draw water from both the boiler and return line.
I believe i will need to add a second pump solely for pumping the hot water circuit - being a fast recovery HW tank i do not believe that gravity circulation would suffice (i.e. conversion to C plan).
If this is a daft idea please offer some constructive alternative. If this is an OK idea, i assume that the heating relay will need to be altered slightly to accommodate the extra pump but other than that do you see any major pitfalls? also, would the existing pump remain prior to the existing diverter valve or would you move it to be after the diverter valve on the HW circuit only?
many thanks in advance
layman1
first i will describe my current system. I have a standard sundial W plan system in conjunction with a standard boiler, an indirect open vented hot water tank and single pump. the HW tank is small (90L), but has a fast recover coil. to maximise the use/efficiency of this tank am told that the boiler water temperature should be set to the maximum, however this is way too hot to be circulating around the heating circuit with small people in the house.
I'm considering getting a plumber in to rearrange pipework slightly but would like some considered opinions first. please don't suggest replacing the whole lot with combi / unvented etc etc etc.
My thoughts are that i need a motorised blending valve such as the ESBE VRG130 with thermostat on the flow line of the central heating circuit to reduce the flow temperature available to something more like 60 celsius by blending with the cooler return line. however, looking at the suggested schematics from ESBE this must be in place BEFORE the pump - which makes perfect sense as it has to draw water from both the boiler and return line.
I believe i will need to add a second pump solely for pumping the hot water circuit - being a fast recovery HW tank i do not believe that gravity circulation would suffice (i.e. conversion to C plan).
If this is a daft idea please offer some constructive alternative. If this is an OK idea, i assume that the heating relay will need to be altered slightly to accommodate the extra pump but other than that do you see any major pitfalls? also, would the existing pump remain prior to the existing diverter valve or would you move it to be after the diverter valve on the HW circuit only?
many thanks in advance
layman1
