We have a heatpump being put in, monobloc separate unit outside and a hotwater cylinder 'unit' inside. I say unit as it comes pre-plumbed with lots of the valves, expansion vessels, pumps, sensors and control boards.
The ideal place for that unit will be in the understairs cupboard in the dead centre of our 1960s bungalow where our old hot water cylinder is. This is not just because lots of the pipework needed already comes here, but for thermal efficiency, but mainly because it is really the closest reasonible place to put it with respect to our ideal outdoors-unit (the actual heat pump), in terms of pipe run length and complexity, exposure to neighbours, accoustics and which wall etc.
The only real problem with that cupboard is that it has no drainage. The new unit needs several drains for condensation (the system can cool as well as heat), for pressure release valves etc.
Installer is telling us that the only possible place for the whole system cant be in that cupboard and it must go where the old boiler is, and the only reason he says this is the lack of drainage. Interestingly there isn't actually any drainage where our old boiler is, there is a sump-level-triggered pump which sends condensate through a pipe that winds its way over two door ways through a wall and into our kitchen.
The building really is impossible to deal with in terms of the floor and trying to route a new drain to a bathrool or the like. That would cost thousands and make the whole install infeasible. We'd have to tear up flooring everywhere, mill through the concrete slab etc.
I asked the installer if a solution like the one the previous (oil boiler) installers used with a pump and pipes that track similarly (going up, and through the ceiling and into the loft and back down the outside of the building is very much possible. But he said that you can't use a pump for a drain for things like condensate and pressure release valves. If this is true either the regs have changed or the previous installer just ignored them.
Any suggestions? Any advice welcome. Sorry for long post!