Single pipe heating - replace?

[GreenFirefly]

We've had a heating engineer in today to move a radiator but as soon as he's looked under the floorboards he's said that it's an ancient single pipe system that wouldn't cope with modern radiators. The result being that it would never heat up properly. He's recommended that the whole system of boiler and radiators be replaced.
Does anyone have any knowledge of a single pipe heating system? If it's going to need replacing we want to do it sooner rather than later when we've decorated and carpeted the whole house. The current system is basic to say the least- no thermostat, no thermostatic valves, just the mechanical timer.

good idea. Single pipe heating is slow to heat rads. If you're renovating, I would. It might also include old iron pipes which will be full of rust and corrosion.

We had planned to replace radiators in each room as we got to it. At least this way it'll all get done at once.
DH also wants to consider replacing the open fire in the front room with a wood burner connected to the boiler. Is this worthwhile? The house is a 4 bed edwardian terrace, but sadly the fireplace is a 60s or 70s mess. If it was original it'd be staying.

If you have a hot water cylinder, you might warm that from the multi fuel. Especially if you buy a large cylinder with two coils.

Two boilers on one system is not very common and unless skilfully done, you end up with the boilers heating each other.

Modern gas boilers are generally very much more powerful than the hot-water output of multifuel stoves, unless you have a large source of free, dry hardwood which would make it more feasible.

p.s.
If you buy a new boiler or stove, don't connect it to the old pipes unless/until they have been thoroughly cleaned and a system filter fitted. Otherwise your new boiler will get clogged with old sediment.

You can't get a single pipe system properly clean because you can't get a forceful flow through the radiators.

I wouldn't bother trying to heat water from a woodburner. I know some people have an effective backburner attached to their wood pellet stove, but it involves you being a slave to the damn thing. We have a woodburner in the living room and we love it, but it is just for heating during the winter. You'd need a massive one to get you any decent amount of hot water too.

thanks for the advice. I suspected the connecting a wood burner in might be more hassle than its worth. the free wood supply is intermittent and is generally old pallets. the pipes will all be new. DH plans lots of trips to the scrap yard with everything that gets taken out.