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ringi

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  1. ringi
    What size pipes connect the far manifold to the heatpump? Have the manifolds been balanced?
  2. ringi
    The Viessmann "defrost buffer" is connected to the CH by a value that enables the buffer to be both disconnected from CH and the CH to be bypassed. When a defrost is pending, the heat pump 1st heat the small buffer (and nothing else) to a high temperature, then uses the hot water in the buffer to defrost the heat pump. This results in the defrost not removing any heat from the CH system, so keeps radiators at a more stable temperature while the defrost is running. (This defrost buffer also contains an electric backup heater, so a defrost of the heat pump is always possible regardless of CH water temperature, CH volume, and outside temperature.)
  3. ringi
    Who did the install? What output is the Veismann Vitocal 151a? What does the service cost to keep the warranty? (That a very good price for one of the beat heatpumps.)
  4. ringi
    How long have the screed been down for?
  5. ringi
    Only if you need to reheat the cylinder quickly, otherwise a smaller heatpump will tend to give better COP for DHW as dt will remain low for longer.
  6. ringi
    If the heatpump is getting many short cycles and the UFH have the thermal mass to cope, what about a time switch that enables heating for 15 minutes per hour? (Set min flow temperature to something like 30c, as most heatpumps don't seem to improve COP if lower. Increase heating time per hour in very cold weather.) (One of the reasons I am thinking of 100mm pipe spacing, so I can get heat from heatpump quickly into UFH thermal mass.)
  7. ringi
    Something I thought I would never say for a heatpump UFH.... What about putting a mixing pump on the UFH manifolds control by a fixed return UFH temperature, and overheat room thermostat that turns off the UFH pump. Then run the home as a single zone with the heatpump controlling the flow temperature based on the requirements of radators. The cylinder would need a little replumbing, so the UFH manifold is connected as if it is an additional radiators. Careful balancing. Should be able to use the redundant zone pump for the UFH manifold by combining with 4 way mixer value.
  8. ringi
    For a gas boiler, maximum efficiency is about 95% and efficiency with a poor design is about 80%. With a heatpump a poor design will give about 200% and a great design about 400%. So much more important to get a low dt and hence low flow temperatures with a heatpump. Heappump efficiency depends on low flow temperatures, gas boiler efficiency depends on keeping return temperatures nicely below 50c. So gas boiler are more forgiving, but work best with heating systems designed to heatpump standards. As to 42mm pipes, I can't see any case it will be used in a home other then to make a low lose header when using multiple pumps without a 4 port buffer. (But a low lose header would use under 1m of pipe.)
  9. ringi
    Clearly that how it should work if the insulation of the buildings is good enough. My plan is to design the loops to match possible zones, but not to install any thermostats or activators. Partly as designing the zones will let me balance the loops to control relative temperature of rooms if required.
  10. ringi
    So how do they decide the required pipe spacing?
  11. ringi
    But they will ask (or should) for target flow temperature and heat loss from each room. Or design for what they think is a "good enough" flow temperature, rather then the lowest that is practical. I am paying heating biils for next 30 years not them..... I am also looking at how we could phase work so remain living in half the property, so need to play with options on the manifolds locations. As no UFH pipes can cross the temporary dust control stud wall, but yet to decide where that will be. Having closely spaced pipes should also give more tolerance for a likely oversized heatpump. Our temperature requirements will be lower then standard calcs assume until we become old.... (Also need to think about bathroom layout to fit in heating, and how much floor area is needed for UFH.)
  12. ringi
    Why not 2nd manifold in kitchen and main manifold in top right off boot room with removing a few bricks to get pipes directly to living room? I would spread pipes out more in boot room so floor is not as uneven temperature. Zones are interesting, as a small zone is only an issue if it can "call for heat". For example my wife study gets a lot of thermal gain, so could have a thermostat to prevent overheating that can never trigger the heatpump to run, with running the rest of our home as a standard openloop.
  13. ringi
    There is no good way of mixing normal radators with UFH, as either the radators have to be huge to run at UFH temperatures, or the flow temperature needs a mixing system to reduce it for UFH. But the efficiency of the heatpump is defined by the emitter that has the highest required flow temperature. Maybe you are happy with bedrooms at below standard temperatures, so will get most of the heat from the rooms below. Fan convector "radators" are one option. Before thinking of UFH for upstairs, remember no UFH work well if it have floorboard over it. If your heatlose was a lot higher I would go as far as saying two independent heat pumps to seperate UFH from radators.
  14. ringi
    The calculated heat loss will likely be assumung the building have more drafts then it does, eg it assumes a low airtightness. Many people don't heat to the temperatures that are used for the calculations. But as you age you are likely to want higher internal temperatures.
  15. ringi
    Good question, unless we install EWI we will never have great insulation levels and wish to get a low flow temperature for a heat pump. The cost of using double the amount of pipe and manifold ports is low compared to everything else about UFH. 100mm pipe space is the standard recommendation for low-temperature heating from many of the UFH companies.
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