Difference between revisions of "The Dream class of monobloc heat pumps"
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They come in four types: air-to-water or ground-to-water, either for domestic or swimming pool heating. | They come in four types: air-to-water or ground-to-water, either for domestic or swimming pool heating. | ||
| − | The domestic ASHP has inch male BSP threads for water in-out pipes. It needs a dedicated 240 volt supply from a circuit-breaker in your electric consumer unit runiing to an isolation switch near the unit. It has no pump. It has a key-pad to change seasonal settings but no useable controls except the run-standby button. You can't control the unit from inside the house, so no programmer or thermostat. | + | The domestic ASHP has inch male BSP threads for water in-out pipes. It needs a dedicated 240 volt supply from a circuit-breaker in your electric consumer unit runiing to an isolation switch near the unit. It has no pump, only a switched connection to run one . It has a key-pad to change seasonal settings but no useable controls except the run-standby button. You can't control the unit from inside the house, so no programmer or thermostat. |
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| + | The unit is always on, there is no "off" switch other than the isolator. It makes its own decisions by measuring (1) ambient temperature (2) output temperature (3) return temperature. The last two can be set through the key-pad. It also monitors its internal refrigerant health. The only other control is the integrated flow switch: it must have flow or it will register a fault and shut down, needing you to go outside and re-start it. | ||
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| + | Water flow is a major design consideration. The integrated flow-switch is set to give full energy transfer and is different for each size of unit. A 5kW unit needs 12.5 littre/minute but a 15kW needs triple that at 37l/m. That's a gushing full bucket every 30 seconds. You have to provide the pump(s) and pipework to allow that. Interestingly, probably lost in translation, the handbook seems to imply you can fit an external flow switch and override the integral one. This would lower efficiency, of course but presumably the unit would go to standby when the output temperature reached its set point. Cycling is considered a no-no for boilers but shouldn't be a worry for electical devices, my refrigerator does it all the time. | ||
Latest revision as of 18:21, 6 December 2022
One species of http://wiki.diyfaq.org.uk/index.php/Heat_Pumps
These are purchaseable by non-professionals so are useable for DIY projects. Most professional installers would not use them. They are a chinese import offered on ebay.
They come in four types: air-to-water or ground-to-water, either for domestic or swimming pool heating.
The domestic ASHP has inch male BSP threads for water in-out pipes. It needs a dedicated 240 volt supply from a circuit-breaker in your electric consumer unit runiing to an isolation switch near the unit. It has no pump, only a switched connection to run one . It has a key-pad to change seasonal settings but no useable controls except the run-standby button. You can't control the unit from inside the house, so no programmer or thermostat.
The unit is always on, there is no "off" switch other than the isolator. It makes its own decisions by measuring (1) ambient temperature (2) output temperature (3) return temperature. The last two can be set through the key-pad. It also monitors its internal refrigerant health. The only other control is the integrated flow switch: it must have flow or it will register a fault and shut down, needing you to go outside and re-start it.
Water flow is a major design consideration. The integrated flow-switch is set to give full energy transfer and is different for each size of unit. A 5kW unit needs 12.5 littre/minute but a 15kW needs triple that at 37l/m. That's a gushing full bucket every 30 seconds. You have to provide the pump(s) and pipework to allow that. Interestingly, probably lost in translation, the handbook seems to imply you can fit an external flow switch and override the integral one. This would lower efficiency, of course but presumably the unit would go to standby when the output temperature reached its set point. Cycling is considered a no-no for boilers but shouldn't be a worry for electical devices, my refrigerator does it all the time.