Hello.
I've got an old farmhouse in rural northern Spain that I'm trying to find a cheap underfloor heating system for. In the unlikely event that it doesn't quickly become obvious anyway, I have only the vaguest idea of what I'm doing and this is just my hopeful idea of a system that might work - I would massively appreciate any comments from people more knowledgeable than me.
I can only get a max. 40A electrical supply for a big house here so I want to run this system on bottled gas, which gets delivered each week.
What I have already is two loops of 16mm qualpex pipe (25m and 80m) set into a 10cm thick concrete floor slab with 6cm rigid insulation below and at the sides and tiles (25m loop) and stuck down (with a UHF suitable sealant) click flooring (80m loop) above.
To connect to the UHF pipes I have a 2 port manifold and a Grundfos 25-60 UPS pump (which has three power settings). This pump is unused but a few years old and I can only find data for its more modern replacements.
What I'm thinking of to complete the system is adding a Junkers WR11-2B (11 litres per minute heated to some heat, I guess - from some googling that looks like equivalent to 10kW or so) gas water heater and an expansion tank and connecting the whole lot together in a closed loop.
To control the system I'm thinking of wiring the pump direct to a timer fuse (15 min intervals) and then basically by trial and error adding run times into the system so that it doesn't overheat and so that I get a decent background heat for the house through the winter (with instant top-up from a wood burning stove). My guess would be 15 mins on and 15 off, so the system doesn't get too hot, and repeated enough to keep the slab at a good temperature. Average winter temperature here is about 12C day and 5C nights with only occasional and very short dips as low as 0.
I've tried to research this in terms of flow rates and so on but I got lost and confused! So my questions to anyone kind enough to take the time to answer are:
1) Does this sound workable?
2) Does the boiler capacity sound about right? (smaller is available, and I prefer a slightly undersized system to a potentially overheating one)
3) Any particular order things should be connected in, like where does the expansion tank go in the system?
4) Assuming I limit the flow more on the short loop, is the return temperature of the water recirculating into the boiler going to get too high?
5) Yes, you guessed it, I have one of those cheap 2 port manifolds off ebay! ...but in an outdoor cupboard so leaks aren't a big deal. It seems to have a temperature sensor mount point on it, and I guess this would be good data to monitor - any suggestions for what to connect here?
5) ...and anything else you think worth mentioning.
Many, many thanks in advance.
I've got an old farmhouse in rural northern Spain that I'm trying to find a cheap underfloor heating system for. In the unlikely event that it doesn't quickly become obvious anyway, I have only the vaguest idea of what I'm doing and this is just my hopeful idea of a system that might work - I would massively appreciate any comments from people more knowledgeable than me.
I can only get a max. 40A electrical supply for a big house here so I want to run this system on bottled gas, which gets delivered each week.
What I have already is two loops of 16mm qualpex pipe (25m and 80m) set into a 10cm thick concrete floor slab with 6cm rigid insulation below and at the sides and tiles (25m loop) and stuck down (with a UHF suitable sealant) click flooring (80m loop) above.
To connect to the UHF pipes I have a 2 port manifold and a Grundfos 25-60 UPS pump (which has three power settings). This pump is unused but a few years old and I can only find data for its more modern replacements.
What I'm thinking of to complete the system is adding a Junkers WR11-2B (11 litres per minute heated to some heat, I guess - from some googling that looks like equivalent to 10kW or so) gas water heater and an expansion tank and connecting the whole lot together in a closed loop.
To control the system I'm thinking of wiring the pump direct to a timer fuse (15 min intervals) and then basically by trial and error adding run times into the system so that it doesn't overheat and so that I get a decent background heat for the house through the winter (with instant top-up from a wood burning stove). My guess would be 15 mins on and 15 off, so the system doesn't get too hot, and repeated enough to keep the slab at a good temperature. Average winter temperature here is about 12C day and 5C nights with only occasional and very short dips as low as 0.
I've tried to research this in terms of flow rates and so on but I got lost and confused! So my questions to anyone kind enough to take the time to answer are:
1) Does this sound workable?
2) Does the boiler capacity sound about right? (smaller is available, and I prefer a slightly undersized system to a potentially overheating one)
3) Any particular order things should be connected in, like where does the expansion tank go in the system?
4) Assuming I limit the flow more on the short loop, is the return temperature of the water recirculating into the boiler going to get too high?
5) Yes, you guessed it, I have one of those cheap 2 port manifolds off ebay! ...but in an outdoor cupboard so leaks aren't a big deal. It seems to have a temperature sensor mount point on it, and I guess this would be good data to monitor - any suggestions for what to connect here?
5) ...and anything else you think worth mentioning.
Many, many thanks in advance.
