My old (non-condensing) boiler is on its last legs, and will probably need replacing when the weather is warmer in the Spring. However, it is going to be difficult to route the condensate pipe.
I live in a bungalow, and the kitchen is galley style, doors north and south, sink (with gully outside) on the east side, boiler on the west side. The routing of the flue is easiest if the boiler stays on the west side of the kitchen, but I have the problem of how to route the condensate drain.
Options seem to be (i) use a condensate pump to lift the condensate into the attic, run across the attic and down the east wall internally or externally, or (ii) use an inverted syphon to take the condensate under the suspended wooden floor. The inverted syphon is a big U-tube, as used by the Romans to take aqueducts across valleys. I have a feeling the inverted syphon was suggested by someone on uk.d-i-y, but I cannot locate the post on Google groups.
My preference is for the inverted syphon -- no pump to go wrong and easier to hide the pipe neatly. However, I feel a bit uncomfortable about having perhaps 1.5 litres condensate sitting in the pipe under the floor (20mm i.d. pipe 5 m long). I would be careful to prevent freezing, running it parallel to existing hot pipes or using a trace heater.
Is there any problem with the inverted syphon that I have missed? Would I fall foul of any regulations with this solution?
MJA